From 991821c86c2fb6cc4104ce679247864dbc070a83 Mon Sep 17 00:00:00 2001
From: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>
Date: Mon, 15 Jul 2013 16:32:34 +0800
Subject: tracing: Use correct config guard CONFIG_STACK_TRACER

We should use CONFIG_STACK_TRACER to guard readme text
of stack tracer related file, not CONFIG_STACKTRACE.

Link: http://lkml.kernel.org/r/51E3B3A2.8080609@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0cd500bffd9b..25b91afc29e0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3537,14 +3537,14 @@ static const char readme_msg[] =
 	"\n  snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
 	"\t\t\t  Read the contents for more information\n"
 #endif
-#ifdef CONFIG_STACKTRACE
+#ifdef CONFIG_STACK_TRACER
 	"  stack_trace\t\t- Shows the max stack trace when active\n"
 	"  stack_max_size\t- Shows current max stack size that was traced\n"
 	"\t\t\t  Write into this file to reset the max size (trigger a new trace)\n"
 #ifdef CONFIG_DYNAMIC_FTRACE
 	"  stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
 #endif
-#endif /* CONFIG_STACKTRACE */
+#endif /* CONFIG_STACK_TRACER */
 ;
 
 static ssize_t
-- 
cgit v1.2.3


From 146c3442f2dd0f50d9431aea5d0d10dfd97c9999 Mon Sep 17 00:00:00 2001
From: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>
Date: Mon, 15 Jul 2013 16:32:44 +0800
Subject: tracing: Use trace_seq_puts()/trace_seq_putc() where possible

For string without format specifiers, use trace_seq_puts()
or trace_seq_putc().

Link: http://lkml.kernel.org/r/51E3B3AC.1000605@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
[ fixed a trace_seq_putc(s, " ") to trace_seq_putc(s, ' ') ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c           | 10 +++----
 kernel/trace/trace_events_filter.c   |  4 +--
 kernel/trace/trace_functions_graph.c | 52 ++++++++++++++++++------------------
 kernel/trace/trace_mmiotrace.c       |  8 +++---
 kernel/trace/trace_output.c          | 14 +++++-----
 kernel/trace/trace_syscalls.c        |  2 +-
 6 files changed, 45 insertions(+), 45 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index e444ff88f0a4..eef2e566b2e7 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -36,11 +36,11 @@ int ring_buffer_print_entry_header(struct trace_seq *s)
 {
 	int ret;
 
-	ret = trace_seq_printf(s, "# compressed entry header\n");
-	ret = trace_seq_printf(s, "\ttype_len    :    5 bits\n");
-	ret = trace_seq_printf(s, "\ttime_delta  :   27 bits\n");
-	ret = trace_seq_printf(s, "\tarray       :   32 bits\n");
-	ret = trace_seq_printf(s, "\n");
+	ret = trace_seq_puts(s, "# compressed entry header\n");
+	ret = trace_seq_puts(s, "\ttype_len    :    5 bits\n");
+	ret = trace_seq_puts(s, "\ttime_delta  :   27 bits\n");
+	ret = trace_seq_puts(s, "\tarray       :   32 bits\n");
+	ret = trace_seq_putc(s, '\n');
 	ret = trace_seq_printf(s, "\tpadding     : type == %d\n",
 			       RINGBUF_TYPE_PADDING);
 	ret = trace_seq_printf(s, "\ttime_extend : type == %d\n",
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 0d883dc057d6..0c7b75a8acc8 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -646,7 +646,7 @@ void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
 	if (filter && filter->filter_string)
 		trace_seq_printf(s, "%s\n", filter->filter_string);
 	else
-		trace_seq_printf(s, "none\n");
+		trace_seq_puts(s, "none\n");
 	mutex_unlock(&event_mutex);
 }
 
@@ -660,7 +660,7 @@ void print_subsystem_event_filter(struct event_subsystem *system,
 	if (filter && filter->filter_string)
 		trace_seq_printf(s, "%s\n", filter->filter_string);
 	else
-		trace_seq_printf(s, DEFAULT_SYS_FILTER_MESSAGE "\n");
+		trace_seq_puts(s, DEFAULT_SYS_FILTER_MESSAGE "\n");
 	mutex_unlock(&event_mutex);
 }
 
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 8388bc99f2ee..d56ae9bae00b 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -446,7 +446,7 @@ print_graph_proc(struct trace_seq *s, pid_t pid)
 
 	/* First spaces to align center */
 	for (i = 0; i < spaces / 2; i++) {
-		ret = trace_seq_printf(s, " ");
+		ret = trace_seq_putc(s, ' ');
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -457,7 +457,7 @@ print_graph_proc(struct trace_seq *s, pid_t pid)
 
 	/* Last spaces to align center */
 	for (i = 0; i < spaces - (spaces / 2); i++) {
-		ret = trace_seq_printf(s, " ");
+		ret = trace_seq_putc(s, ' ');
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -503,7 +503,7 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
  ------------------------------------------
 
  */
-	ret = trace_seq_printf(s,
+	ret = trace_seq_puts(s,
 		" ------------------------------------------\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
@@ -516,7 +516,7 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 	if (ret == TRACE_TYPE_PARTIAL_LINE)
 		return TRACE_TYPE_PARTIAL_LINE;
 
-	ret = trace_seq_printf(s, " => ");
+	ret = trace_seq_puts(s, " => ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
@@ -524,7 +524,7 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 	if (ret == TRACE_TYPE_PARTIAL_LINE)
 		return TRACE_TYPE_PARTIAL_LINE;
 
-	ret = trace_seq_printf(s,
+	ret = trace_seq_puts(s,
 		"\n ------------------------------------------\n\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
@@ -645,7 +645,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 			ret = print_graph_proc(s, pid);
 			if (ret == TRACE_TYPE_PARTIAL_LINE)
 				return TRACE_TYPE_PARTIAL_LINE;
-			ret = trace_seq_printf(s, " | ");
+			ret = trace_seq_puts(s, " | ");
 			if (!ret)
 				return TRACE_TYPE_PARTIAL_LINE;
 		}
@@ -657,9 +657,9 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 		return ret;
 
 	if (type == TRACE_GRAPH_ENT)
-		ret = trace_seq_printf(s, "==========>");
+		ret = trace_seq_puts(s, "==========>");
 	else
-		ret = trace_seq_printf(s, "<==========");
+		ret = trace_seq_puts(s, "<==========");
 
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
@@ -668,7 +668,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 	if (ret != TRACE_TYPE_HANDLED)
 		return ret;
 
-	ret = trace_seq_printf(s, "\n");
+	ret = trace_seq_putc(s, '\n');
 
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
@@ -705,13 +705,13 @@ trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 		len += strlen(nsecs_str);
 	}
 
-	ret = trace_seq_printf(s, " us ");
+	ret = trace_seq_puts(s, " us ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
 	/* Print remaining spaces to fit the row's width */
 	for (i = len; i < 7; i++) {
-		ret = trace_seq_printf(s, " ");
+		ret = trace_seq_putc(s, ' ');
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -731,13 +731,13 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s,
 	/* No real adata, just filling the column with spaces */
 	switch (duration) {
 	case DURATION_FILL_FULL:
-		ret = trace_seq_printf(s, "              |  ");
+		ret = trace_seq_puts(s, "              |  ");
 		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 	case DURATION_FILL_START:
-		ret = trace_seq_printf(s, "  ");
+		ret = trace_seq_puts(s, "  ");
 		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 	case DURATION_FILL_END:
-		ret = trace_seq_printf(s, " |");
+		ret = trace_seq_puts(s, " |");
 		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 	}
 
@@ -745,10 +745,10 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s,
 	if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
 		/* Duration exceeded 100 msecs */
 		if (duration > 100000ULL)
-			ret = trace_seq_printf(s, "! ");
+			ret = trace_seq_puts(s, "! ");
 		/* Duration exceeded 10 msecs */
 		else if (duration > 10000ULL)
-			ret = trace_seq_printf(s, "+ ");
+			ret = trace_seq_puts(s, "+ ");
 	}
 
 	/*
@@ -757,7 +757,7 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s,
 	 * to fill out the space.
 	 */
 	if (ret == -1)
-		ret = trace_seq_printf(s, "  ");
+		ret = trace_seq_puts(s, "  ");
 
 	/* Catching here any failure happenned above */
 	if (!ret)
@@ -767,7 +767,7 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s,
 	if (ret != TRACE_TYPE_HANDLED)
 		return ret;
 
-	ret = trace_seq_printf(s, "|  ");
+	ret = trace_seq_puts(s, "|  ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
@@ -817,7 +817,7 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 
 	/* Function */
 	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_printf(s, " ");
+		ret = trace_seq_putc(s, ' ');
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -858,7 +858,7 @@ print_graph_entry_nested(struct trace_iterator *iter,
 
 	/* Function */
 	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_printf(s, " ");
+		ret = trace_seq_putc(s, ' ');
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -917,7 +917,7 @@ print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 
-		ret = trace_seq_printf(s, " | ");
+		ret = trace_seq_puts(s, " | ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -1117,7 +1117,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 
 	/* Closing brace */
 	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_printf(s, " ");
+		ret = trace_seq_putc(s, ' ');
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -1129,7 +1129,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 	 * belongs to, write out the function name.
 	 */
 	if (func_match) {
-		ret = trace_seq_printf(s, "}\n");
+		ret = trace_seq_puts(s, "}\n");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	} else {
@@ -1179,13 +1179,13 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 	/* Indentation */
 	if (depth > 0)
 		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
-			ret = trace_seq_printf(s, " ");
+			ret = trace_seq_putc(s, ' ');
 			if (!ret)
 				return TRACE_TYPE_PARTIAL_LINE;
 		}
 
 	/* The comment */
-	ret = trace_seq_printf(s, "/* ");
+	ret = trace_seq_puts(s, "/* ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
@@ -1216,7 +1216,7 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 		s->len--;
 	}
 
-	ret = trace_seq_printf(s, " */\n");
+	ret = trace_seq_puts(s, " */\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index a5e8f4878bfa..b3dcfb2f0fef 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -90,7 +90,7 @@ static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
 	if (drv)
 		ret += trace_seq_printf(s, " %s\n", drv->name);
 	else
-		ret += trace_seq_printf(s, " \n");
+		ret += trace_seq_puts(s, " \n");
 	return ret;
 }
 
@@ -107,7 +107,7 @@ static void mmio_pipe_open(struct trace_iterator *iter)
 	struct header_iter *hiter;
 	struct trace_seq *s = &iter->seq;
 
-	trace_seq_printf(s, "VERSION 20070824\n");
+	trace_seq_puts(s, "VERSION 20070824\n");
 
 	hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 	if (!hiter)
@@ -209,7 +209,7 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 			(rw->value >> 0) & 0xff, rw->pc, 0);
 		break;
 	default:
-		ret = trace_seq_printf(s, "rw what?\n");
+		ret = trace_seq_puts(s, "rw what?\n");
 		break;
 	}
 	if (ret)
@@ -245,7 +245,7 @@ static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 			secs, usec_rem, m->map_id, 0UL, 0);
 		break;
 	default:
-		ret = trace_seq_printf(s, "map what?\n");
+		ret = trace_seq_puts(s, "map what?\n");
 		break;
 	}
 	if (ret)
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index bb922d9ee51b..34e7cbac0c9c 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -78,7 +78,7 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_printf(s, "%s", field->buf);
+	ret = trace_seq_puts(s, field->buf);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
@@ -558,14 +558,14 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 			if (ret)
 				ret = trace_seq_puts(s, "??");
 			if (ret)
-				ret = trace_seq_puts(s, "\n");
+				ret = trace_seq_putc(s, '\n');
 			continue;
 		}
 		if (!ret)
 			break;
 		if (ret)
 			ret = seq_print_user_ip(s, mm, ip, sym_flags);
-		ret = trace_seq_puts(s, "\n");
+		ret = trace_seq_putc(s, '\n');
 	}
 
 	if (mm)
@@ -579,7 +579,7 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
 	int ret;
 
 	if (!ip)
-		return trace_seq_printf(s, "0");
+		return trace_seq_putc(s, '0');
 
 	if (sym_flags & TRACE_ITER_SYM_OFFSET)
 		ret = seq_print_sym_offset(s, "%s", ip);
@@ -964,14 +964,14 @@ static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 		goto partial;
 
 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
-		if (!trace_seq_printf(s, " <-"))
+		if (!trace_seq_puts(s, " <-"))
 			goto partial;
 		if (!seq_print_ip_sym(s,
 				      field->parent_ip,
 				      flags))
 			goto partial;
 	}
-	if (!trace_seq_printf(s, "\n"))
+	if (!trace_seq_putc(s, '\n'))
 		goto partial;
 
 	return TRACE_TYPE_HANDLED;
@@ -1210,7 +1210,7 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
 
 		if (!seq_print_ip_sym(s, *p, flags))
 			goto partial;
-		if (!trace_seq_puts(s, "\n"))
+		if (!trace_seq_putc(s, '\n'))
 			goto partial;
 	}
 
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 322e16461072..061156215721 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -175,7 +175,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 	entry = syscall_nr_to_meta(syscall);
 
 	if (!entry) {
-		trace_seq_printf(s, "\n");
+		trace_seq_putc(s, '\n');
 		return TRACE_TYPE_HANDLED;
 	}
 
-- 
cgit v1.2.3


From d611851b421731e2afd9cb956daae001af57a423 Mon Sep 17 00:00:00 2001
From: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>
Date: Mon, 15 Jul 2013 16:32:50 +0800
Subject: tracing: Typo fix on ring buffer comments

There have some mismatch between comments with
real function name, update it.

This patch also add some missed function arguments
description.

Link: http://lkml.kernel.org/r/51E3B3B2.4080307@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index eef2e566b2e7..cc2f66f68dc5 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1066,7 +1066,7 @@ static int rb_check_list(struct ring_buffer_per_cpu *cpu_buffer,
 }
 
 /**
- * check_pages - integrity check of buffer pages
+ * rb_check_pages - integrity check of buffer pages
  * @cpu_buffer: CPU buffer with pages to test
  *
  * As a safety measure we check to make sure the data pages have not
@@ -1258,7 +1258,7 @@ static int rb_cpu_notify(struct notifier_block *self,
 #endif
 
 /**
- * ring_buffer_alloc - allocate a new ring_buffer
+ * __ring_buffer_alloc - allocate a new ring_buffer
  * @size: the size in bytes per cpu that is needed.
  * @flags: attributes to set for the ring buffer.
  *
@@ -1607,6 +1607,7 @@ static void update_pages_handler(struct work_struct *work)
  * ring_buffer_resize - resize the ring buffer
  * @buffer: the buffer to resize.
  * @size: the new size.
+ * @cpu_id: the cpu buffer to resize
  *
  * Minimum size is 2 * BUF_PAGE_SIZE.
  *
@@ -3956,11 +3957,11 @@ EXPORT_SYMBOL_GPL(ring_buffer_consume);
  * expected.
  *
  * After a sequence of ring_buffer_read_prepare calls, the user is
- * expected to make at least one call to ring_buffer_prepare_sync.
+ * expected to make at least one call to ring_buffer_read_prepare_sync.
  * Afterwards, ring_buffer_read_start is invoked to get things going
  * for real.
  *
- * This overall must be paired with ring_buffer_finish.
+ * This overall must be paired with ring_buffer_read_finish.
  */
 struct ring_buffer_iter *
 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu)
@@ -4009,7 +4010,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_read_prepare_sync);
  * an intervening ring_buffer_read_prepare_sync must have been
  * performed.
  *
- * Must be paired with ring_buffer_finish.
+ * Must be paired with ring_buffer_read_finish.
  */
 void
 ring_buffer_read_start(struct ring_buffer_iter *iter)
@@ -4031,7 +4032,7 @@ ring_buffer_read_start(struct ring_buffer_iter *iter)
 EXPORT_SYMBOL_GPL(ring_buffer_read_start);
 
 /**
- * ring_buffer_finish - finish reading the iterator of the buffer
+ * ring_buffer_read_finish - finish reading the iterator of the buffer
  * @iter: The iterator retrieved by ring_buffer_start
  *
  * This re-enables the recording to the buffer, and frees the
@@ -4346,6 +4347,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
 /**
  * ring_buffer_alloc_read_page - allocate a page to read from buffer
  * @buffer: the buffer to allocate for.
+ * @cpu: the cpu buffer to allocate.
  *
  * This function is used in conjunction with ring_buffer_read_page.
  * When reading a full page from the ring buffer, these functions
@@ -4403,7 +4405,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_free_read_page);
  * to swap with a page in the ring buffer.
  *
  * for example:
- *	rpage = ring_buffer_alloc_read_page(buffer);
+ *	rpage = ring_buffer_alloc_read_page(buffer, cpu);
  *	if (!rpage)
  *		return error;
  *	ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0);
-- 
cgit v1.2.3


From b8ebfd3f7113b63dda93d76bfec638c00e6bd514 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 17 Jun 2013 19:02:04 +0200
Subject: tracing/function: Avoid perf_trace_buf_*() if
 event_function.perf_events is empty

perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL)
make no sense if hlist_empty(head). Change perf_ftrace_function_call()
to check event_function.perf_events beforehand.

Link: http://lkml.kernel.org/r/20130617170204.GA19803@redhat.com

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_event_perf.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 84b1e045faba..12df5573086e 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -266,6 +266,10 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
 	struct pt_regs regs;
 	int rctx;
 
+	head = this_cpu_ptr(event_function.perf_events);
+	if (hlist_empty(head))
+		return;
+
 #define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \
 		    sizeof(u64)) - sizeof(u32))
 
@@ -279,8 +283,6 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
 
 	entry->ip = ip;
 	entry->parent_ip = parent_ip;
-
-	head = this_cpu_ptr(event_function.perf_events);
 	perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, 0,
 			      1, &regs, head, NULL);
 
-- 
cgit v1.2.3


From 421c7860c6e1989da3962fafdd6699316c9f8e20 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 17 Jun 2013 19:02:07 +0200
Subject: tracing/syscall: Avoid perf_trace_buf_*() if sys_data->perf_events is
 empty

perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL)
make no sense if hlist_empty(head). Change perf_syscall_enter/exit()
to check sys_data->{enter,exit}_event->perf_events beforehand.

Link: http://lkml.kernel.org/r/20130617170207.GA19806@redhat.com

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_syscalls.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 061156215721..ac0085777fbd 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -566,6 +566,10 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 	if (!sys_data)
 		return;
 
+	head = this_cpu_ptr(sys_data->enter_event->perf_events);
+	if (hlist_empty(head))
+		return;
+
 	/* get the size after alignment with the u32 buffer size field */
 	size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
 	size = ALIGN(size + sizeof(u32), sizeof(u64));
@@ -583,8 +587,6 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 	rec->nr = syscall_nr;
 	syscall_get_arguments(current, regs, 0, sys_data->nb_args,
 			       (unsigned long *)&rec->args);
-
-	head = this_cpu_ptr(sys_data->enter_event->perf_events);
 	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }
 
@@ -642,6 +644,10 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 	if (!sys_data)
 		return;
 
+	head = this_cpu_ptr(sys_data->exit_event->perf_events);
+	if (hlist_empty(head))
+		return;
+
 	/* We can probably do that at build time */
 	size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
@@ -661,8 +667,6 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 
 	rec->nr = syscall_nr;
 	rec->ret = syscall_get_return_value(current, regs);
-
-	head = this_cpu_ptr(sys_data->exit_event->perf_events);
 	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }
 
-- 
cgit v1.2.3


From cd92bf61d6d70bd3eb33b46d600e3f3eb9c5778a Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 17 Jun 2013 19:02:11 +0200
Subject: tracing/perf: Move the PERF_MAX_TRACE_SIZE check into
 perf_trace_buf_prepare()

Every perf_trace_buf_prepare() caller does
WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is
almost the same.

Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes
the meaning of _ONCE, but I think this is fine.

	- 4947014 2932448 10104832  17984294  1126b26 vmlinux
	+ 4948422 2932448 10104832  17985702  11270a6 vmlinux

on my build.

Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_event_perf.c |  4 ++++
 kernel/trace/trace_kprobe.c     |  6 ------
 kernel/trace/trace_syscalls.c   | 12 ------------
 kernel/trace/trace_uprobe.c     |  2 --
 4 files changed, 4 insertions(+), 20 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 12df5573086e..80c36bcf66e8 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -236,6 +236,10 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
 
 	BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
 
+	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
+			"perf buffer not large enough"))
+		return NULL;
+
 	pc = preempt_count();
 
 	*rctxp = perf_swevent_get_recursion_context();
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7ed6976493c8..ae6ce835b023 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1087,9 +1087,6 @@ kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs)
 	__size = sizeof(*entry) + tp->size + dsize;
 	size = ALIGN(__size + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		     "profile buffer not large enough"))
-		return;
 
 	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
 	if (!entry)
@@ -1120,9 +1117,6 @@ kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri,
 	__size = sizeof(*entry) + tp->size + dsize;
 	size = ALIGN(__size + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		     "profile buffer not large enough"))
-		return;
 
 	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
 	if (!entry)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index ac0085777fbd..8fd03657bc7d 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -575,10 +575,6 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 	size = ALIGN(size + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
 
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		      "perf buffer not large enough"))
-		return;
-
 	rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
 				sys_data->enter_event->event.type, regs, &rctx);
 	if (!rec)
@@ -652,14 +648,6 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 	size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
 
-	/*
-	 * Impossible, but be paranoid with the future
-	 * How to put this check outside runtime?
-	 */
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		"exit event has grown above perf buffer size"))
-		return;
-
 	rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
 				sys_data->exit_event->event.type, regs, &rctx);
 	if (!rec)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index d5d0cd368a56..a23d2d71188e 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -818,8 +818,6 @@ static void uprobe_perf_print(struct trace_uprobe *tu,
 
 	size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
 	size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32);
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
-		return;
 
 	preempt_disable();
 	head = this_cpu_ptr(call->perf_events);
-- 
cgit v1.2.3


From a232e270dcb55a70ad3241bc6fc160fd9b5c9e6c Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Date: Tue, 9 Jul 2013 18:35:26 +0900
Subject: tracing/kprobe: Wait for disabling all running kprobe handlers

Wait for disabling all running kprobe handlers when a kprobe
event is disabled, since the caller, trace_remove_event_call()
supposes that a removing event is disabled completely by
disabling the event.
With this change, ftrace can ensure that there is no running
event handlers after disabling it.

Link: http://lkml.kernel.org/r/20130709093526.20138.93100.stgit@mhiramat-M0-7522

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index ae6ce835b023..3811487e7a7a 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -243,11 +243,11 @@ find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
 static int
 disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 {
+	struct event_file_link *link = NULL;
+	int wait = 0;
 	int ret = 0;
 
 	if (file) {
-		struct event_file_link *link;
-
 		link = find_event_file_link(tp, file);
 		if (!link) {
 			ret = -EINVAL;
@@ -255,10 +255,7 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 		}
 
 		list_del_rcu(&link->list);
-		/* synchronize with kprobe_trace_func/kretprobe_trace_func */
-		synchronize_sched();
-		kfree(link);
-
+		wait = 1;
 		if (!list_empty(&tp->files))
 			goto out;
 
@@ -271,8 +268,22 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 			disable_kretprobe(&tp->rp);
 		else
 			disable_kprobe(&tp->rp.kp);
+		wait = 1;
 	}
  out:
+	if (wait) {
+		/*
+		 * Synchronize with kprobe_trace_func/kretprobe_trace_func
+		 * to ensure disabled (all running handlers are finished).
+		 * This is not only for kfree(), but also the caller,
+		 * trace_remove_event_call() supposes it for releasing
+		 * event_call related objects, which will be accessed in
+		 * the kprobe_trace_func/kretprobe_trace_func.
+		 */
+		synchronize_sched();
+		kfree(link);	/* Ignored if link == NULL */
+	}
+
 	return ret;
 }
 
-- 
cgit v1.2.3


From 609e85a70bcd0eedf4ec60639dbcfb1ab011e054 Mon Sep 17 00:00:00 2001
From: Alexander Z Lam <azl@google.com>
Date: Wed, 10 Jul 2013 17:34:34 -0700
Subject: tracing: Fix error handling to ensure instances can always be removed

Remove debugfs directories for tracing instances during creation if an error
occurs causing the trace_array for that instance to not be added to
ftrace_trace_arrays. If the directory continues to exist after the error, it
cannot be removed because the respective trace_array is not in
ftrace_trace_arrays.

Link: http://lkml.kernel.org/r/1373502874-1706-2-git-send-email-azl@google.com

Cc: stable@vger.kernel.org # 3.10
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 25b91afc29e0..7c3da7bca05b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5973,8 +5973,10 @@ static int new_instance_create(const char *name)
 		goto out_free_tr;
 
 	ret = event_trace_add_tracer(tr->dir, tr);
-	if (ret)
+	if (ret) {
+		debugfs_remove_recursive(tr->dir);
 		goto out_free_tr;
+	}
 
 	init_tracer_debugfs(tr, tr->dir);
 
-- 
cgit v1.2.3


From f77d09a384676bde6445413949d9d2c508ff3e62 Mon Sep 17 00:00:00 2001
From: Alexander Z Lam <azl@google.com>
Date: Thu, 18 Jul 2013 11:18:44 -0700
Subject: tracing: Miscellaneous fixes for trace_array ref counting

Some error paths did not handle ref counting properly, and some trace files need
ref counting.

Link: http://lkml.kernel.org/r/1374171524-11948-1-git-send-email-azl@google.com

Cc: stable@vger.kernel.org # 3.10
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c        | 24 ++++++++++++++++++------
 kernel/trace/trace_events.c | 21 +++++++++++++++++++--
 2 files changed, 37 insertions(+), 8 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7c3da7bca05b..7d9ceab42564 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3008,7 +3008,6 @@ static int tracing_release(struct inode *inode, struct file *file)
 
 	iter = m->private;
 	tr = iter->tr;
-	trace_array_put(tr);
 
 	mutex_lock(&trace_types_lock);
 
@@ -3023,6 +3022,9 @@ static int tracing_release(struct inode *inode, struct file *file)
 	if (!iter->snapshot)
 		/* reenable tracing if it was previously enabled */
 		tracing_start_tr(tr);
+
+	__trace_array_put(tr);
+
 	mutex_unlock(&trace_types_lock);
 
 	mutex_destroy(&iter->mutex);
@@ -3447,6 +3449,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 static int tracing_trace_options_open(struct inode *inode, struct file *file)
 {
 	struct trace_array *tr = inode->i_private;
+	int ret;
 
 	if (tracing_disabled)
 		return -ENODEV;
@@ -3454,7 +3457,11 @@ static int tracing_trace_options_open(struct inode *inode, struct file *file)
 	if (trace_array_get(tr) < 0)
 		return -ENODEV;
 
-	return single_open(file, tracing_trace_options_show, inode->i_private);
+	ret = single_open(file, tracing_trace_options_show, inode->i_private);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
 }
 
 static const struct file_operations tracing_iter_fops = {
@@ -3958,6 +3965,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
 	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 	if (!iter) {
 		ret = -ENOMEM;
+		__trace_array_put(tr);
 		goto out;
 	}
 
@@ -4704,21 +4712,24 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
 			ret = PTR_ERR(iter);
 	} else {
 		/* Writes still need the seq_file to hold the private data */
+		ret = -ENOMEM;
 		m = kzalloc(sizeof(*m), GFP_KERNEL);
 		if (!m)
-			return -ENOMEM;
+			goto out;
 		iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 		if (!iter) {
 			kfree(m);
-			return -ENOMEM;
+			goto out;
 		}
+		ret = 0;
+
 		iter->tr = tr;
 		iter->trace_buffer = &tc->tr->max_buffer;
 		iter->cpu_file = tc->cpu;
 		m->private = iter;
 		file->private_data = m;
 	}
-
+out:
 	if (ret < 0)
 		trace_array_put(tr);
 
@@ -5328,9 +5339,10 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
 }
 
 static const struct file_operations tracing_stats_fops = {
-	.open		= tracing_open_generic,
+	.open		= tracing_open_generic_tc,
 	.read		= tracing_stats_read,
 	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tc,
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7d854290bf81..7a75cb22eab7 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1218,6 +1218,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 
 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
 static int ftrace_event_set_open(struct inode *inode, struct file *file);
+static int ftrace_event_release(struct inode *inode, struct file *file);
 
 static const struct seq_operations show_event_seq_ops = {
 	.start = t_start,
@@ -1245,7 +1246,7 @@ static const struct file_operations ftrace_set_event_fops = {
 	.read = seq_read,
 	.write = ftrace_event_write,
 	.llseek = seq_lseek,
-	.release = seq_release,
+	.release = ftrace_event_release,
 };
 
 static const struct file_operations ftrace_enable_fops = {
@@ -1323,6 +1324,15 @@ ftrace_event_open(struct inode *inode, struct file *file,
 	return ret;
 }
 
+static int ftrace_event_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+
+	return seq_release(inode, file);
+}
+
 static int
 ftrace_event_avail_open(struct inode *inode, struct file *file)
 {
@@ -1336,12 +1346,19 @@ ftrace_event_set_open(struct inode *inode, struct file *file)
 {
 	const struct seq_operations *seq_ops = &show_set_event_seq_ops;
 	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
 
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
 		ftrace_clear_events(tr);
 
-	return ftrace_event_open(inode, file, seq_ops);
+	ret = ftrace_event_open(inode, file, seq_ops);
+	if (ret < 0)
+		trace_array_put(tr);
+	return ret;
 }
 
 static struct event_subsystem *
-- 
cgit v1.2.3


From 8f768993394a8c0d3801033c11fd86ce8c88dcac Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Thu, 18 Jul 2013 14:41:51 -0400
Subject: tracing: Add ref_data to function and fgraph tracer structs

The selftest for function and function graph tracers are defined as
__init, as they are only executed at boot up. The "tracer" structs
that are associated to those tracers are not setup as __init as they
are used after boot. To stop mismatch warnings, those structures
need to be annotated with __ref_data.

Currently, the tracer structures are defined to __read_mostly, as they
do not really change. But in the future they should be converted to
consts, but that will take a little work because they have a "next"
pointer that gets updated when they are registered. That will have to
wait till the next major release.

Link: http://lkml.kernel.org/r/1373596735.17876.84.camel@gandalf.local.home

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.h                 | 9 +++++++++
 kernel/trace/trace_functions.c       | 2 +-
 kernel/trace/trace_functions_graph.c | 2 +-
 3 files changed, 11 insertions(+), 2 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 4a4f6e1828b6..57b7bb0d39b7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -680,6 +680,15 @@ extern int trace_selftest_startup_sched_switch(struct tracer *trace,
 					       struct trace_array *tr);
 extern int trace_selftest_startup_branch(struct tracer *trace,
 					 struct trace_array *tr);
+/*
+ * Tracer data references selftest functions that only occur
+ * on boot up. These can be __init functions. Thus, when selftests
+ * are enabled, then the tracers need to reference __init functions.
+ */
+#define __tracer_data		__refdata
+#else
+/* Tracers are seldom changed. Optimize when selftests are disabled. */
+#define __tracer_data		__read_mostly
 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 
 extern void *head_page(struct trace_array_cpu *data);
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index b863f93b30f3..38fe1483c508 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -199,7 +199,7 @@ static int func_set_flag(u32 old_flags, u32 bit, int set)
 	return 0;
 }
 
-static struct tracer function_trace __read_mostly =
+static struct tracer function_trace __tracer_data =
 {
 	.name		= "function",
 	.init		= function_trace_init,
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index d56ae9bae00b..b5c09242683d 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1448,7 +1448,7 @@ static struct trace_event graph_trace_ret_event = {
 	.funcs		= &graph_functions
 };
 
-static struct tracer graph_trace __read_mostly = {
+static struct tracer graph_trace __tracer_data = {
 	.name		= "function_graph",
 	.open		= graph_trace_open,
 	.pipe_open	= graph_trace_open,
-- 
cgit v1.2.3


From 7710b639953b791610f0022a7d52d9801c93b969 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Thu, 18 Jul 2013 20:47:10 +0200
Subject: tracing: Simplify the iteration logic in f_start/f_next

f_next() looks overcomplicated, and it is not strictly correct
even if this doesn't matter.

Say, FORMAT_FIELD_SEPERATOR should not return NULL (means EOF)
if trace_get_fields() returns an empty list, we should simply
advance to FORMAT_PRINTFMT as we do when we find the end of list.

1. Change f_next() to return "struct list_head *" rather than
   "ftrace_event_field *", and change f_show() to do list_entry().

   This simplifies the code a bit, only f_show() needs to know
   about ftrace_event_field, and f_next() can play with ->prev
   directly

2. Change f_next() to not play with ->prev / return inside the
   switch() statement. It can simply set node = head/common_head,
   the prev-or-advance-to-the-next-magic below does all work.

While at it. f_start() looks overcomplicated too. I don't think
*pos == 0 makes sense as a separate case, just change this code
to do "while" instead of "do/while".

The patch also moves f_start() down, close to f_stop(). This is
purely cosmetic, just to make the locking added by the next patch
more clear/visible.

Link: http://lkml.kernel.org/r/20130718184710.GA4783@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 60 +++++++++++++++++----------------------------
 1 file changed, 22 insertions(+), 38 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7a75cb22eab7..76defd91f9b4 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -826,59 +826,33 @@ enum {
 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	struct ftrace_event_call *call = m->private;
-	struct ftrace_event_field *field;
 	struct list_head *common_head = &ftrace_common_fields;
 	struct list_head *head = trace_get_fields(call);
+	struct list_head *node = v;
 
 	(*pos)++;
 
 	switch ((unsigned long)v) {
 	case FORMAT_HEADER:
-		if (unlikely(list_empty(common_head)))
-			return NULL;
-
-		field = list_entry(common_head->prev,
-				   struct ftrace_event_field, link);
-		return field;
+		node = common_head;
+		break;
 
 	case FORMAT_FIELD_SEPERATOR:
-		if (unlikely(list_empty(head)))
-			return NULL;
-
-		field = list_entry(head->prev, struct ftrace_event_field, link);
-		return field;
+		node = head;
+		break;
 
 	case FORMAT_PRINTFMT:
 		/* all done */
 		return NULL;
 	}
 
-	field = v;
-	if (field->link.prev == common_head)
+	node = node->prev;
+	if (node == common_head)
 		return (void *)FORMAT_FIELD_SEPERATOR;
-	else if (field->link.prev == head)
+	else if (node == head)
 		return (void *)FORMAT_PRINTFMT;
-
-	field = list_entry(field->link.prev, struct ftrace_event_field, link);
-
-	return field;
-}
-
-static void *f_start(struct seq_file *m, loff_t *pos)
-{
-	loff_t l = 0;
-	void *p;
-
-	/* Start by showing the header */
-	if (!*pos)
-		return (void *)FORMAT_HEADER;
-
-	p = (void *)FORMAT_HEADER;
-	do {
-		p = f_next(m, p, &l);
-	} while (p && l < *pos);
-
-	return p;
+	else
+		return node;
 }
 
 static int f_show(struct seq_file *m, void *v)
@@ -904,8 +878,7 @@ static int f_show(struct seq_file *m, void *v)
 		return 0;
 	}
 
-	field = v;
-
+	field = list_entry(v, struct ftrace_event_field, link);
 	/*
 	 * Smartly shows the array type(except dynamic array).
 	 * Normal:
@@ -932,6 +905,17 @@ static int f_show(struct seq_file *m, void *v)
 	return 0;
 }
 
+static void *f_start(struct seq_file *m, loff_t *pos)
+{
+	void *p = (void *)FORMAT_HEADER;
+	loff_t l = 0;
+
+	while (l < *pos && p)
+		p = f_next(m, p, &l);
+
+	return p;
+}
+
 static void f_stop(struct seq_file *m, void *p)
 {
 }
-- 
cgit v1.2.3


From cd458ba9d5a5592d37b5145e560071e91ea762ac Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Thu, 18 Jul 2013 20:47:12 +0200
Subject: tracing: Do not (ab)use trace_seq in event_id_read()

event_id_read() has no reason to kmalloc "struct trace_seq"
(more than PAGE_SIZE!), it can use a small buffer instead.

Note: "if (*ppos) return 0" looks strange and even wrong,
simple_read_from_buffer() handles ppos != 0 case corrrectly.

And it seems that almost every user of trace_seq in this file
should be converted too. Unless you use seq_open(), trace_seq
buys nothing compared to the raw buffer, but it needs a bit
more memory and code.

Link: http://lkml.kernel.org/r/20130718184712.GA4786@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 76defd91f9b4..898f868833f2 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -947,23 +947,14 @@ static ssize_t
 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 {
 	struct ftrace_event_call *call = filp->private_data;
-	struct trace_seq *s;
-	int r;
+	char buf[32];
+	int len;
 
 	if (*ppos)
 		return 0;
 
-	s = kmalloc(sizeof(*s), GFP_KERNEL);
-	if (!s)
-		return -ENOMEM;
-
-	trace_seq_init(s);
-	trace_seq_printf(s, "%d\n", call->event.type);
-
-	r = simple_read_from_buffer(ubuf, cnt, ppos,
-				    s->buffer, s->len);
-	kfree(s);
-	return r;
+	len = sprintf(buf, "%d\n", call->event.type);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
 }
 
 static ssize_t
-- 
cgit v1.2.3


From a644a7e9587802eabb2e229177606f6a74a60fc1 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 19 Jul 2013 16:20:36 +0200
Subject: tracing: Kill trace_array->waiter

Trivial. trace_array->waiter has no users since 6eaaa5d5
"tracing/core: use appropriate waiting on trace_pipe".

Link: http://lkml.kernel.org/r/20130719142036.GA1594@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.h | 1 -
 1 file changed, 1 deletion(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 57b7bb0d39b7..e7d643b8a907 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -214,7 +214,6 @@ struct trace_array {
 	struct dentry		*event_dir;
 	struct list_head	systems;
 	struct list_head	events;
-	struct task_struct	*waiter;
 	int			ref;
 };
 
-- 
cgit v1.2.3


From e70e78e3c83b536730e31231dd9b979768d8df3c Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 19 Jul 2013 17:36:44 +0200
Subject: tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open()

tracing_buffers_open() does trace_array_get() and then it wrongly
inrcements tr->ref again under trace_types_lock. This means that
every caller leaks trace_array:

	# cd /sys/kernel/debug/tracing/
	# mkdir instances/X
	# true < instances/X/per_cpu/cpu0/trace_pipe_raw
	# rmdir instances/X
	rmdir: failed to remove `instances/X': Device or resource busy

Link: http://lkml.kernel.org/r/20130719153644.GA18899@redhat.com

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 2 --
 1 file changed, 2 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7d9ceab42564..3f2477713aca 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4959,8 +4959,6 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
 
 	mutex_lock(&trace_types_lock);
 
-	tr->ref++;
-
 	info->iter.tr		= tr;
 	info->iter.cpu_file	= tc->cpu;
 	info->iter.trace	= tr->current_trace;
-- 
cgit v1.2.3


From 649e9c70da6bfbeb563193a35d3424a5aa7c0d38 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 23 Jul 2013 17:25:54 +0200
Subject: tracing: Introduce trace_create_cpu_file() and tracing_get_cpu()

Every "file_operations" used by tracing_init_debugfs_percpu is buggy.
f_op->open/etc does:

	1. struct trace_cpu *tc = inode->i_private;
	   struct trace_array *tr = tc->tr;

	2. trace_array_get(tr) or fail;

	3. do_something(tc);

But tc (and tr) can be already freed before trace_array_get() is called.
And it doesn't matter whether this file is per-cpu or it was created by
init_tracer_debugfs(), free_percpu() or kfree() are equally bad.

Note that even 1. is not safe, the freed memory can be unmapped. But even
if it was safe trace_array_get() can wrongly succeed if we also race with
the next new_instance_create() which can re-allocate the same tr, or tc
was overwritten and ->tr points to the valid tr. In this case 3. uses the
freed/reused memory.

Add the new trivial helper, trace_create_cpu_file() which simply calls
trace_create_file() and encodes "cpu" in "struct inode". Another helper,
tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS.

The patch abuses ->i_cdev to encode the number, it is never used unless
the file is S_ISCHR(). But we could use something else, say, i_bytes or
even ->d_fsdata. In any case this hack is hidden inside these 2 helpers,
it would be trivial to change them if needed.

This patch only changes tracing_init_debugfs_percpu() to use the new
trace_create_cpu_file(), the next patches will change file_operations.

Note: tracing_get_cpu(inode) is always safe but you can't trust the
result unless trace_array_get() was called, without trace_types_lock
which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS.

Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 50 ++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 14 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3f2477713aca..cfff63c2148a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2843,6 +2843,17 @@ static int s_show(struct seq_file *m, void *v)
 	return 0;
 }
 
+/*
+ * Should be used after trace_array_get(), trace_types_lock
+ * ensures that i_cdev was already initialized.
+ */
+static inline int tracing_get_cpu(struct inode *inode)
+{
+	if (inode->i_cdev) /* See trace_create_cpu_file() */
+		return (long)inode->i_cdev - 1;
+	return RING_BUFFER_ALL_CPUS;
+}
+
 static const struct seq_operations tracer_seq_ops = {
 	.start		= s_start,
 	.next		= s_next,
@@ -5529,6 +5540,17 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
 	return tr->percpu_dir;
 }
 
+static struct dentry *
+trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
+		      void *data, long cpu, const struct file_operations *fops)
+{
+	struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
+
+	if (ret) /* See tracing_get_cpu() */
+		ret->d_inode->i_cdev = (void *)(cpu + 1);
+	return ret;
+}
+
 static void
 tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 {
@@ -5548,28 +5570,28 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 	}
 
 	/* per cpu trace_pipe */
-	trace_create_file("trace_pipe", 0444, d_cpu,
-			(void *)&data->trace_cpu, &tracing_pipe_fops);
+	trace_create_cpu_file("trace_pipe", 0444, d_cpu,
+				&data->trace_cpu, cpu, &tracing_pipe_fops);
 
 	/* per cpu trace */
-	trace_create_file("trace", 0644, d_cpu,
-			(void *)&data->trace_cpu, &tracing_fops);
+	trace_create_cpu_file("trace", 0644, d_cpu,
+				&data->trace_cpu, cpu, &tracing_fops);
 
-	trace_create_file("trace_pipe_raw", 0444, d_cpu,
-			(void *)&data->trace_cpu, &tracing_buffers_fops);
+	trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
+				&data->trace_cpu, cpu, &tracing_buffers_fops);
 
-	trace_create_file("stats", 0444, d_cpu,
-			(void *)&data->trace_cpu, &tracing_stats_fops);
+	trace_create_cpu_file("stats", 0444, d_cpu,
+				&data->trace_cpu, cpu, &tracing_stats_fops);
 
-	trace_create_file("buffer_size_kb", 0444, d_cpu,
-			(void *)&data->trace_cpu, &tracing_entries_fops);
+	trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
+				&data->trace_cpu, cpu, &tracing_entries_fops);
 
 #ifdef CONFIG_TRACER_SNAPSHOT
-	trace_create_file("snapshot", 0644, d_cpu,
-			  (void *)&data->trace_cpu, &snapshot_fops);
+	trace_create_cpu_file("snapshot", 0644, d_cpu,
+				&data->trace_cpu, cpu, &snapshot_fops);
 
-	trace_create_file("snapshot_raw", 0444, d_cpu,
-			(void *)&data->trace_cpu, &snapshot_raw_fops);
+	trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
+				&data->trace_cpu, cpu, &snapshot_raw_fops);
 #endif
 }
 
-- 
cgit v1.2.3


From 15544209cb0b5312e5220a9337a1fe61d1a1f2d9 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 23 Jul 2013 17:25:57 +0200
Subject: tracing: Change tracing_pipe_fops() to rely on tracing_get_cpu()

tracing_open_pipe() is racy, the memory inode->i_private points to
can be already freed.

Change debugfs_create_file("trace_pipe", data) callers to to pass
"data = tr", tracing_open_pipe() can use tracing_get_cpu().

Link: http://lkml.kernel.org/r/20130723152557.GA23717@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index cfff63c2148a..51a99ef2a6e5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3959,8 +3959,7 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf,
 
 static int tracing_open_pipe(struct inode *inode, struct file *filp)
 {
-	struct trace_cpu *tc = inode->i_private;
-	struct trace_array *tr = tc->tr;
+	struct trace_array *tr = inode->i_private;
 	struct trace_iterator *iter;
 	int ret = 0;
 
@@ -4006,9 +4005,9 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
 	if (trace_clocks[tr->clock_id].in_ns)
 		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
 
-	iter->cpu_file = tc->cpu;
-	iter->tr = tc->tr;
-	iter->trace_buffer = &tc->tr->trace_buffer;
+	iter->tr = tr;
+	iter->trace_buffer = &tr->trace_buffer;
+	iter->cpu_file = tracing_get_cpu(inode);
 	mutex_init(&iter->mutex);
 	filp->private_data = iter;
 
@@ -4031,8 +4030,7 @@ fail:
 static int tracing_release_pipe(struct inode *inode, struct file *file)
 {
 	struct trace_iterator *iter = file->private_data;
-	struct trace_cpu *tc = inode->i_private;
-	struct trace_array *tr = tc->tr;
+	struct trace_array *tr = inode->i_private;
 
 	mutex_lock(&trace_types_lock);
 
@@ -5571,7 +5569,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 
 	/* per cpu trace_pipe */
 	trace_create_cpu_file("trace_pipe", 0444, d_cpu,
-				&data->trace_cpu, cpu, &tracing_pipe_fops);
+				tr, cpu, &tracing_pipe_fops);
 
 	/* per cpu trace */
 	trace_create_cpu_file("trace", 0644, d_cpu,
@@ -6157,7 +6155,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 			(void *)&tr->trace_cpu, &tracing_fops);
 
 	trace_create_file("trace_pipe", 0444, d_tracer,
-			(void *)&tr->trace_cpu, &tracing_pipe_fops);
+			  tr, &tracing_pipe_fops);
 
 	trace_create_file("buffer_size_kb", 0644, d_tracer,
 			(void *)&tr->trace_cpu, &tracing_entries_fops);
-- 
cgit v1.2.3


From 46ef2be0d1d5ccea0c41bb606143586daadd537c Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 23 Jul 2013 17:26:00 +0200
Subject: tracing: Change tracing_buffers_fops to rely on tracing_get_cpu()

tracing_buffers_open() is racy, the memory inode->i_private points
to can be already freed.

Change debugfs_create_file("trace_pipe_raw", data) caller to pass
"data = tr", tracing_buffers_open() can use tracing_get_cpu().

Change debugfs_create_file("snapshot_raw_fops", data) caller too,
this file uses tracing_buffers_open/release.

Link: http://lkml.kernel.org/r/20130723152600.GA23720@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 51a99ef2a6e5..30c058a56ffb 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4949,8 +4949,7 @@ static const struct file_operations snapshot_raw_fops = {
 
 static int tracing_buffers_open(struct inode *inode, struct file *filp)
 {
-	struct trace_cpu *tc = inode->i_private;
-	struct trace_array *tr = tc->tr;
+	struct trace_array *tr = inode->i_private;
 	struct ftrace_buffer_info *info;
 	int ret;
 
@@ -4969,7 +4968,7 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
 	mutex_lock(&trace_types_lock);
 
 	info->iter.tr		= tr;
-	info->iter.cpu_file	= tc->cpu;
+	info->iter.cpu_file	= tracing_get_cpu(inode);
 	info->iter.trace	= tr->current_trace;
 	info->iter.trace_buffer = &tr->trace_buffer;
 	info->spare		= NULL;
@@ -5576,7 +5575,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 				&data->trace_cpu, cpu, &tracing_fops);
 
 	trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
-				&data->trace_cpu, cpu, &tracing_buffers_fops);
+				tr, cpu, &tracing_buffers_fops);
 
 	trace_create_cpu_file("stats", 0444, d_cpu,
 				&data->trace_cpu, cpu, &tracing_stats_fops);
@@ -5589,7 +5588,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 				&data->trace_cpu, cpu, &snapshot_fops);
 
 	trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
-				&data->trace_cpu, cpu, &snapshot_raw_fops);
+				tr, cpu, &snapshot_raw_fops);
 #endif
 }
 
-- 
cgit v1.2.3


From 4d3435b8a4c3357695e09c5e7a3bf73a19fca5b0 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 23 Jul 2013 17:26:03 +0200
Subject: tracing: Change tracing_stats_fops to rely on tracing_get_cpu()

tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.

1. Change one of its users, tracing_stats_fops, to use
   tracing_*_generic_tr() instead.

2. Change trace_create_cpu_file("stats", data) to pass "data = tr".

3. Change tracing_stats_read() to use tracing_get_cpu().

Link: http://lkml.kernel.org/r/20130723152603.GA23727@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 30c058a56ffb..e29dc8f69aac 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2982,7 +2982,6 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
 	filp->private_data = inode->i_private;
 
 	return 0;
-	
 }
 
 static int tracing_open_generic_tc(struct inode *inode, struct file *filp)
@@ -5285,14 +5284,14 @@ static ssize_t
 tracing_stats_read(struct file *filp, char __user *ubuf,
 		   size_t count, loff_t *ppos)
 {
-	struct trace_cpu *tc = filp->private_data;
-	struct trace_array *tr = tc->tr;
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
 	struct trace_buffer *trace_buf = &tr->trace_buffer;
+	int cpu = tracing_get_cpu(inode);
 	struct trace_seq *s;
 	unsigned long cnt;
 	unsigned long long t;
 	unsigned long usec_rem;
-	int cpu = tc->cpu;
 
 	s = kmalloc(sizeof(*s), GFP_KERNEL);
 	if (!s)
@@ -5345,10 +5344,10 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
 }
 
 static const struct file_operations tracing_stats_fops = {
-	.open		= tracing_open_generic_tc,
+	.open		= tracing_open_generic_tr,
 	.read		= tracing_stats_read,
 	.llseek		= generic_file_llseek,
-	.release	= tracing_release_generic_tc,
+	.release	= tracing_release_generic_tr,
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -5578,7 +5577,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 				tr, cpu, &tracing_buffers_fops);
 
 	trace_create_cpu_file("stats", 0444, d_cpu,
-				&data->trace_cpu, cpu, &tracing_stats_fops);
+				tr, cpu, &tracing_stats_fops);
 
 	trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
 				&data->trace_cpu, cpu, &tracing_entries_fops);
-- 
cgit v1.2.3


From 0bc392ee46d0fd8e6b678457ef71f074f19a03c5 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 23 Jul 2013 17:26:06 +0200
Subject: tracing: Change tracing_entries_fops to rely on tracing_get_cpu()

tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.

1. Change its last user, tracing_entries_fops, to use
   tracing_*_generic_tr() instead.

2. Change debugfs_create_file("buffer_size_kb", data) callers
   to pass "data = tr".

3. Change tracing_entries_read() and tracing_entries_write() to
   use tracing_get_cpu().

4. Kill the no longer used tracing_open_generic_tc() and
   tracing_release_generic_tc().

Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 49 ++++++++++++-------------------------------------
 1 file changed, 12 insertions(+), 37 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e29dc8f69aac..68b46851666f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2984,23 +2984,6 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
 	return 0;
 }
 
-static int tracing_open_generic_tc(struct inode *inode, struct file *filp)
-{
-	struct trace_cpu *tc = inode->i_private;
-	struct trace_array *tr = tc->tr;
-
-	if (tracing_disabled)
-		return -ENODEV;
-
-	if (trace_array_get(tr) < 0)
-		return -ENODEV;
-
-	filp->private_data = inode->i_private;
-
-	return 0;
-	
-}
-
 static int tracing_release(struct inode *inode, struct file *file)
 {
 	struct seq_file *m = file->private_data;
@@ -3054,15 +3037,6 @@ static int tracing_release_generic_tr(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static int tracing_release_generic_tc(struct inode *inode, struct file *file)
-{
-	struct trace_cpu *tc = inode->i_private;
-	struct trace_array *tr = tc->tr;
-
-	trace_array_put(tr);
-	return 0;
-}
-
 static int tracing_single_release_tr(struct inode *inode, struct file *file)
 {
 	struct trace_array *tr = inode->i_private;
@@ -4382,15 +4356,16 @@ static ssize_t
 tracing_entries_read(struct file *filp, char __user *ubuf,
 		     size_t cnt, loff_t *ppos)
 {
-	struct trace_cpu *tc = filp->private_data;
-	struct trace_array *tr = tc->tr;
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
+	int cpu = tracing_get_cpu(inode);
 	char buf[64];
 	int r = 0;
 	ssize_t ret;
 
 	mutex_lock(&trace_types_lock);
 
-	if (tc->cpu == RING_BUFFER_ALL_CPUS) {
+	if (cpu == RING_BUFFER_ALL_CPUS) {
 		int cpu, buf_size_same;
 		unsigned long size;
 
@@ -4417,7 +4392,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf,
 		} else
 			r = sprintf(buf, "X\n");
 	} else
-		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10);
+		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
 
 	mutex_unlock(&trace_types_lock);
 
@@ -4429,7 +4404,8 @@ static ssize_t
 tracing_entries_write(struct file *filp, const char __user *ubuf,
 		      size_t cnt, loff_t *ppos)
 {
-	struct trace_cpu *tc = filp->private_data;
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
 	unsigned long val;
 	int ret;
 
@@ -4443,8 +4419,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 
 	/* value is in KB */
 	val <<= 10;
-
-	ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu);
+	ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
 	if (ret < 0)
 		return ret;
 
@@ -4892,11 +4867,11 @@ static const struct file_operations tracing_pipe_fops = {
 };
 
 static const struct file_operations tracing_entries_fops = {
-	.open		= tracing_open_generic_tc,
+	.open		= tracing_open_generic_tr,
 	.read		= tracing_entries_read,
 	.write		= tracing_entries_write,
 	.llseek		= generic_file_llseek,
-	.release	= tracing_release_generic_tc,
+	.release	= tracing_release_generic_tr,
 };
 
 static const struct file_operations tracing_total_entries_fops = {
@@ -5580,7 +5555,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 				tr, cpu, &tracing_stats_fops);
 
 	trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
-				&data->trace_cpu, cpu, &tracing_entries_fops);
+				tr, cpu, &tracing_entries_fops);
 
 #ifdef CONFIG_TRACER_SNAPSHOT
 	trace_create_cpu_file("snapshot", 0644, d_cpu,
@@ -6156,7 +6131,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 			  tr, &tracing_pipe_fops);
 
 	trace_create_file("buffer_size_kb", 0644, d_tracer,
-			(void *)&tr->trace_cpu, &tracing_entries_fops);
+			  tr, &tracing_entries_fops);
 
 	trace_create_file("buffer_total_size_kb", 0444, d_tracer,
 			  tr, &tracing_total_entries_fops);
-- 
cgit v1.2.3


From 6484c71cbc170634fa131b6d022d86d61686b88b Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 23 Jul 2013 17:26:10 +0200
Subject: tracing: Change tracing_fops/snapshot_fops to rely on
 tracing_get_cpu()

tracing_open() and tracing_snapshot_open() are racy, the memory
inode->i_private points to can be already freed.

Convert these last users of "inode->i_private == trace_cpu" to
use "i_private = trace_array" and rely on tracing_get_cpu().

v2: incorporate the fix from Steven, tracing_release() must not
    blindly dereference file->private_data unless we know that
    the file was opened for reading.

Link: http://lkml.kernel.org/r/20130723152610.GA23737@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 50 ++++++++++++++++++++++----------------------------
 1 file changed, 22 insertions(+), 28 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 68b46851666f..dd7780ddde08 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2862,9 +2862,9 @@ static const struct seq_operations tracer_seq_ops = {
 };
 
 static struct trace_iterator *
-__tracing_open(struct trace_array *tr, struct trace_cpu *tc,
-	       struct inode *inode, struct file *file, bool snapshot)
+__tracing_open(struct inode *inode, struct file *file, bool snapshot)
 {
+	struct trace_array *tr = inode->i_private;
 	struct trace_iterator *iter;
 	int cpu;
 
@@ -2905,8 +2905,8 @@ __tracing_open(struct trace_array *tr, struct trace_cpu *tc,
 		iter->trace_buffer = &tr->trace_buffer;
 	iter->snapshot = snapshot;
 	iter->pos = -1;
+	iter->cpu_file = tracing_get_cpu(inode);
 	mutex_init(&iter->mutex);
-	iter->cpu_file = tc->cpu;
 
 	/* Notify the tracer early; before we stop tracing. */
 	if (iter->trace && iter->trace->open)
@@ -2986,22 +2986,18 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
 
 static int tracing_release(struct inode *inode, struct file *file)
 {
+	struct trace_array *tr = inode->i_private;
 	struct seq_file *m = file->private_data;
 	struct trace_iterator *iter;
-	struct trace_array *tr;
 	int cpu;
 
-	/* Writes do not use seq_file, need to grab tr from inode */
 	if (!(file->f_mode & FMODE_READ)) {
-		struct trace_cpu *tc = inode->i_private;
-
-		trace_array_put(tc->tr);
+		trace_array_put(tr);
 		return 0;
 	}
 
+	/* Writes do not use seq_file */
 	iter = m->private;
-	tr = iter->tr;
-
 	mutex_lock(&trace_types_lock);
 
 	for_each_tracing_cpu(cpu) {
@@ -3048,8 +3044,7 @@ static int tracing_single_release_tr(struct inode *inode, struct file *file)
 
 static int tracing_open(struct inode *inode, struct file *file)
 {
-	struct trace_cpu *tc = inode->i_private;
-	struct trace_array *tr = tc->tr;
+	struct trace_array *tr = inode->i_private;
 	struct trace_iterator *iter;
 	int ret = 0;
 
@@ -3057,16 +3052,17 @@ static int tracing_open(struct inode *inode, struct file *file)
 		return -ENODEV;
 
 	/* If this file was open for write, then erase contents */
-	if ((file->f_mode & FMODE_WRITE) &&
-	    (file->f_flags & O_TRUNC)) {
-		if (tc->cpu == RING_BUFFER_ALL_CPUS)
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		int cpu = tracing_get_cpu(inode);
+
+		if (cpu == RING_BUFFER_ALL_CPUS)
 			tracing_reset_online_cpus(&tr->trace_buffer);
 		else
-			tracing_reset(&tr->trace_buffer, tc->cpu);
+			tracing_reset(&tr->trace_buffer, cpu);
 	}
 
 	if (file->f_mode & FMODE_READ) {
-		iter = __tracing_open(tr, tc, inode, file, false);
+		iter = __tracing_open(inode, file, false);
 		if (IS_ERR(iter))
 			ret = PTR_ERR(iter);
 		else if (trace_flags & TRACE_ITER_LATENCY_FMT)
@@ -4680,8 +4676,7 @@ struct ftrace_buffer_info {
 #ifdef CONFIG_TRACER_SNAPSHOT
 static int tracing_snapshot_open(struct inode *inode, struct file *file)
 {
-	struct trace_cpu *tc = inode->i_private;
-	struct trace_array *tr = tc->tr;
+	struct trace_array *tr = inode->i_private;
 	struct trace_iterator *iter;
 	struct seq_file *m;
 	int ret = 0;
@@ -4690,7 +4685,7 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
 		return -ENODEV;
 
 	if (file->f_mode & FMODE_READ) {
-		iter = __tracing_open(tr, tc, inode, file, true);
+		iter = __tracing_open(inode, file, true);
 		if (IS_ERR(iter))
 			ret = PTR_ERR(iter);
 	} else {
@@ -4707,8 +4702,8 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
 		ret = 0;
 
 		iter->tr = tr;
-		iter->trace_buffer = &tc->tr->max_buffer;
-		iter->cpu_file = tc->cpu;
+		iter->trace_buffer = &tr->max_buffer;
+		iter->cpu_file = tracing_get_cpu(inode);
 		m->private = iter;
 		file->private_data = m;
 	}
@@ -5525,7 +5520,6 @@ trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
 static void
 tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 {
-	struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 	struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
 	struct dentry *d_cpu;
 	char cpu_dir[30]; /* 30 characters should be more than enough */
@@ -5546,7 +5540,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 
 	/* per cpu trace */
 	trace_create_cpu_file("trace", 0644, d_cpu,
-				&data->trace_cpu, cpu, &tracing_fops);
+				tr, cpu, &tracing_fops);
 
 	trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
 				tr, cpu, &tracing_buffers_fops);
@@ -5559,7 +5553,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 
 #ifdef CONFIG_TRACER_SNAPSHOT
 	trace_create_cpu_file("snapshot", 0644, d_cpu,
-				&data->trace_cpu, cpu, &snapshot_fops);
+				tr, cpu, &snapshot_fops);
 
 	trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
 				tr, cpu, &snapshot_raw_fops);
@@ -6125,7 +6119,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 			  tr, &tracing_iter_fops);
 
 	trace_create_file("trace", 0644, d_tracer,
-			(void *)&tr->trace_cpu, &tracing_fops);
+			  tr, &tracing_fops);
 
 	trace_create_file("trace_pipe", 0444, d_tracer,
 			  tr, &tracing_pipe_fops);
@@ -6146,11 +6140,11 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 			  &trace_clock_fops);
 
 	trace_create_file("tracing_on", 0644, d_tracer,
-			    tr, &rb_simple_fops);
+			  tr, &rb_simple_fops);
 
 #ifdef CONFIG_TRACER_SNAPSHOT
 	trace_create_file("snapshot", 0644, d_tracer,
-			  (void *)&tr->trace_cpu, &snapshot_fops);
+			  tr, &snapshot_fops);
 #endif
 
 	for_each_tracing_cpu(cpu)
-- 
cgit v1.2.3


From 9c01fe4593db123c5a72dc36f0400f776e92c954 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 23 Jul 2013 17:26:13 +0200
Subject: tracing: Kill trace_cpu struct/members

After the previous changes trace_array_cpu->trace_cpu and
trace_array->trace_cpu becomes write-only. Remove these members
and kill "struct trace_cpu" as well.

As a side effect this also removes memset(per_cpu_memory, 0).
It was not needed, alloc_percpu() returns zero-filled memory.

Link: http://lkml.kernel.org/r/20130723152613.GA23741@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 21 ---------------------
 kernel/trace/trace.h |  8 --------
 2 files changed, 29 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dd7780ddde08..69cba470ea96 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5865,17 +5865,6 @@ struct dentry *trace_instance_dir;
 static void
 init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer);
 
-static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf)
-{
-	int cpu;
-
-	for_each_tracing_cpu(cpu) {
-		memset(per_cpu_ptr(buf->data, cpu), 0, sizeof(struct trace_array_cpu));
-		per_cpu_ptr(buf->data, cpu)->trace_cpu.cpu = cpu;
-		per_cpu_ptr(buf->data, cpu)->trace_cpu.tr = tr;
-	}
-}
-
 static int
 allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
 {
@@ -5893,8 +5882,6 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
 		return -ENOMEM;
 	}
 
-	init_trace_buffers(tr, buf);
-
 	/* Allocate the first page for all buffers */
 	set_buffer_entries(&tr->trace_buffer,
 			   ring_buffer_size(tr->trace_buffer.buffer, 0));
@@ -5961,10 +5948,6 @@ static int new_instance_create(const char *name)
 	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
 		goto out_free_tr;
 
-	/* Holder for file callbacks */
-	tr->trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
-	tr->trace_cpu.tr = tr;
-
 	tr->dir = debugfs_create_dir(name, trace_instance_dir);
 	if (!tr->dir)
 		goto out_free_tr;
@@ -6438,10 +6421,6 @@ __init static int tracer_alloc_buffers(void)
 
 	global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
 
-	/* Holder for file callbacks */
-	global_trace.trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
-	global_trace.trace_cpu.tr = &global_trace;
-
 	INIT_LIST_HEAD(&global_trace.systems);
 	INIT_LIST_HEAD(&global_trace.events);
 	list_add(&global_trace.list, &ftrace_trace_arrays);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e7d643b8a907..afaae41b0a02 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -130,19 +130,12 @@ enum trace_flag_type {
 
 struct trace_array;
 
-struct trace_cpu {
-	struct trace_array	*tr;
-	struct dentry		*dir;
-	int			cpu;
-};
-
 /*
  * The CPU trace array - it consists of thousands of trace entries
  * plus some other descriptor data: (for example which task started
  * the trace, etc.)
  */
 struct trace_array_cpu {
-	struct trace_cpu	trace_cpu;
 	atomic_t		disabled;
 	void			*buffer_page;	/* ring buffer spare */
 
@@ -196,7 +189,6 @@ struct trace_array {
 	bool			allocated_snapshot;
 #endif
 	int			buffer_disabled;
-	struct trace_cpu	trace_cpu;	/* place holder */
 #ifdef CONFIG_FTRACE_SYSCALLS
 	int			sys_refcount_enter;
 	int			sys_refcount_exit;
-- 
cgit v1.2.3


From 195a8afc7ac962f8da795549fe38e825f1372b0d Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Tue, 23 Jul 2013 22:06:15 -0400
Subject: ftrace: Add check for NULL regs if ops has SAVE_REGS set

If a ftrace ops is registered with the SAVE_REGS flag set, and there's
already a ops registered to one of its functions but without the
SAVE_REGS flag, there's a small race window where the SAVE_REGS ops gets
added to the list of callbacks to call for that function before the
callback trampoline gets set to save the regs.

The problem is, the function is not currently saving regs, which opens
a small race window where the ops that is expecting regs to be passed
to it, wont. This can cause a crash if the callback were to reference
the regs, as the SAVE_REGS guarantees that regs will be set.

To fix this, we add a check in the loop case where it checks if the ops
has the SAVE_REGS flag set, and if so, it will ignore it if regs is
not set.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 67708f46baae..8ce9eefc5bb4 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1441,12 +1441,22 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
  * the hashes are freed with call_rcu_sched().
  */
 static int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
 	struct ftrace_hash *filter_hash;
 	struct ftrace_hash *notrace_hash;
 	int ret;
 
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	/*
+	 * There's a small race when adding ops that the ftrace handler
+	 * that wants regs, may be called without them. We can not
+	 * allow that handler to be called if regs is NULL.
+	 */
+	if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
+		return 0;
+#endif
+
 	filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
 	notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
 
@@ -4218,7 +4228,7 @@ static inline void ftrace_startup_enable(int command) { }
 # define ftrace_shutdown_sysctl()	do { } while (0)
 
 static inline int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
 	return 1;
 }
@@ -4241,7 +4251,7 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
 	do_for_each_ftrace_op(op, ftrace_control_list) {
 		if (!(op->flags & FTRACE_OPS_FL_STUB) &&
 		    !ftrace_function_local_disabled(op) &&
-		    ftrace_ops_test(op, ip))
+		    ftrace_ops_test(op, ip, regs))
 			op->func(ip, parent_ip, op, regs);
 	} while_for_each_ftrace_op(op);
 	trace_recursion_clear(TRACE_CONTROL_BIT);
@@ -4274,7 +4284,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 	 */
 	preempt_disable_notrace();
 	do_for_each_ftrace_op(op, ftrace_ops_list) {
-		if (ftrace_ops_test(op, ip))
+		if (ftrace_ops_test(op, ip, regs))
 			op->func(ip, parent_ip, op, regs);
 	} while_for_each_ftrace_op(op);
 	preempt_enable_notrace();
-- 
cgit v1.2.3


From 09d8091c024ec88d1541d93eb8ddb2bd5cf10c39 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Tue, 23 Jul 2013 22:21:59 -0400
Subject: tracing: Remove locking trace_types_lock from
 tracing_reset_all_online_cpus()

Commit a82274151af "tracing: Protect ftrace_trace_arrays list in trace_events.c"
added taking the trace_types_lock mutex in trace_events.c as there were
several locations that needed it for protection. Unfortunately, it also
encapsulated a call to tracing_reset_all_online_cpus() which also takes
the trace_types_lock, causing a deadlock.

This happens when a module has tracepoints and has been traced. When the
module is removed, the trace events module notifier will grab the
trace_types_lock, do a bunch of clean ups, and also clears the buffer
by calling tracing_reset_all_online_cpus. This doesn't happen often
which explains why it wasn't caught right away.

Commit a82274151af was marked for stable, which means this must be
sent to stable too.

Link: http://lkml.kernel.org/r/51EEC646.7070306@broadcom.com

Reported-by: Arend van Spril <arend@broadcom.com>
Tested-by: Arend van Spriel <arend@broadcom.com>
Cc: Alexander Z Lam <azl@google.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 69cba470ea96..882ec1dd1515 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1224,18 +1224,17 @@ void tracing_reset_current(int cpu)
 	tracing_reset(&global_trace.trace_buffer, cpu);
 }
 
+/* Must have trace_types_lock held */
 void tracing_reset_all_online_cpus(void)
 {
 	struct trace_array *tr;
 
-	mutex_lock(&trace_types_lock);
 	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
 		tracing_reset_online_cpus(&tr->trace_buffer);
 #ifdef CONFIG_TRACER_MAX_TRACE
 		tracing_reset_online_cpus(&tr->max_buffer);
 #endif
 	}
-	mutex_unlock(&trace_types_lock);
 }
 
 #define SAVED_CMDLINES 128
-- 
cgit v1.2.3


From 1a11126bcb7c93c289bf3218fa546fd3b0c0df8b Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 26 Jul 2013 19:25:32 +0200
Subject: tracing: Turn event/id->i_private into call->event.type

event_id_read() is racy, ftrace_event_call can be already freed
by trace_remove_event_call() callers.

Change event_create_dir() to pass "data = call->event.type", this
is all event_id_read() needs. ftrace_event_id_fops no longer needs
tracing_open_generic().

We add the new helper, event_file_data(), to read ->i_private, it
will have more users.

Note: currently ACCESS_ONCE() and "id != 0" check are not needed,
but we are going to change event_remove/rmdir to clear ->i_private.

Link: http://lkml.kernel.org/r/20130726172532.GA3605@redhat.com

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 898f868833f2..c2d13c528c3c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -409,6 +409,11 @@ static void put_system(struct ftrace_subsystem_dir *dir)
 	mutex_unlock(&event_mutex);
 }
 
+static void *event_file_data(struct file *filp)
+{
+	return ACCESS_ONCE(file_inode(filp)->i_private);
+}
+
 /*
  * Open and update trace_array ref count.
  * Must have the current trace_array passed to it.
@@ -946,14 +951,18 @@ static int trace_format_open(struct inode *inode, struct file *file)
 static ssize_t
 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 {
-	struct ftrace_event_call *call = filp->private_data;
+	int id = (long)event_file_data(filp);
 	char buf[32];
 	int len;
 
 	if (*ppos)
 		return 0;
 
-	len = sprintf(buf, "%d\n", call->event.type);
+	if (unlikely(!id))
+		return -ENODEV;
+
+	len = sprintf(buf, "%d\n", id);
+
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
 }
 
@@ -1240,7 +1249,6 @@ static const struct file_operations ftrace_event_format_fops = {
 };
 
 static const struct file_operations ftrace_event_id_fops = {
-	.open = tracing_open_generic,
 	.read = event_id_read,
 	.llseek = default_llseek,
 };
@@ -1488,8 +1496,8 @@ event_create_dir(struct dentry *parent,
 
 #ifdef CONFIG_PERF_EVENTS
 	if (call->event.type && call->class->reg)
-		trace_create_file("id", 0444, file->dir, call,
-		 		  id);
+		trace_create_file("id", 0444, file->dir,
+				  (void *)(long)call->event.type, id);
 #endif
 
 	/*
-- 
cgit v1.2.3


From bc6f6b08dee5645770efb4b76186ded313f23752 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 26 Jul 2013 19:25:36 +0200
Subject: tracing: Change event_enable/disable_read() to verify i_private !=
 NULL

tracing_open_generic_file() is racy, ftrace_event_file can be
already freed by rmdir or trace_remove_event_call().

Change event_enable_read() and event_disable_read() to read and
verify "file = i_private" under event_mutex.

This fixes nothing, but now we can change debugfs_remove("enable")
callers to nullify ->i_private and fix the the problem.

Link: http://lkml.kernel.org/r/20130726172536.GA3612@redhat.com

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index c2d13c528c3c..3dfa8419d0dc 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -684,15 +684,25 @@ static ssize_t
 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 		  loff_t *ppos)
 {
-	struct ftrace_event_file *file = filp->private_data;
+	struct ftrace_event_file *file;
+	unsigned long flags;
 	char buf[4] = "0";
 
-	if (file->flags & FTRACE_EVENT_FL_ENABLED &&
-	    !(file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
+	mutex_lock(&event_mutex);
+	file = event_file_data(filp);
+	if (likely(file))
+		flags = file->flags;
+	mutex_unlock(&event_mutex);
+
+	if (!file)
+		return -ENODEV;
+
+	if (flags & FTRACE_EVENT_FL_ENABLED &&
+	    !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
 		strcpy(buf, "1");
 
-	if (file->flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
-	    file->flags & FTRACE_EVENT_FL_SOFT_MODE)
+	if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
+	    flags & FTRACE_EVENT_FL_SOFT_MODE)
 		strcat(buf, "*");
 
 	strcat(buf, "\n");
@@ -704,13 +714,10 @@ static ssize_t
 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		   loff_t *ppos)
 {
-	struct ftrace_event_file *file = filp->private_data;
+	struct ftrace_event_file *file;
 	unsigned long val;
 	int ret;
 
-	if (!file)
-		return -EINVAL;
-
 	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 	if (ret)
 		return ret;
@@ -722,8 +729,11 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	switch (val) {
 	case 0:
 	case 1:
+		ret = -ENODEV;
 		mutex_lock(&event_mutex);
-		ret = ftrace_event_enable_disable(file, val);
+		file = event_file_data(filp);
+		if (likely(file))
+			ret = ftrace_event_enable_disable(file, val);
 		mutex_unlock(&event_mutex);
 		break;
 
-- 
cgit v1.2.3


From e2912b091c26b8ea95e5e00a43a7ac620f6c94a6 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 26 Jul 2013 19:25:40 +0200
Subject: tracing: Change event_filter_read/write to verify i_private != NULL

event_filter_read/write() are racy, ftrace_event_call can be already
freed by trace_remove_event_call() callers.

1. Shift mutex_lock(event_mutex) from print/apply_event_filter to
   the callers.

2. Change the callers, event_filter_read() and event_filter_write()
   to read i_private under this mutex and abort if it is NULL.

This fixes nothing, but now we can change debugfs_remove("filter")
callers to nullify ->i_private and fix the the problem.

Link: http://lkml.kernel.org/r/20130726172540.GA3619@redhat.com

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c        | 26 +++++++++++++++++++-------
 kernel/trace/trace_events_filter.c | 17 ++++++-----------
 2 files changed, 25 insertions(+), 18 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 3dfa8419d0dc..1d7b6d03cd51 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -980,21 +980,28 @@ static ssize_t
 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 		  loff_t *ppos)
 {
-	struct ftrace_event_call *call = filp->private_data;
+	struct ftrace_event_call *call;
 	struct trace_seq *s;
-	int r;
+	int r = -ENODEV;
 
 	if (*ppos)
 		return 0;
 
 	s = kmalloc(sizeof(*s), GFP_KERNEL);
+
 	if (!s)
 		return -ENOMEM;
 
 	trace_seq_init(s);
 
-	print_event_filter(call, s);
-	r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+	mutex_lock(&event_mutex);
+	call = event_file_data(filp);
+	if (call)
+		print_event_filter(call, s);
+	mutex_unlock(&event_mutex);
+
+	if (call)
+		r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 
 	kfree(s);
 
@@ -1005,9 +1012,9 @@ static ssize_t
 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		   loff_t *ppos)
 {
-	struct ftrace_event_call *call = filp->private_data;
+	struct ftrace_event_call *call;
 	char *buf;
-	int err;
+	int err = -ENODEV;
 
 	if (cnt >= PAGE_SIZE)
 		return -EINVAL;
@@ -1022,7 +1029,12 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	}
 	buf[cnt] = '\0';
 
-	err = apply_event_filter(call, buf);
+	mutex_lock(&event_mutex);
+	call = event_file_data(filp);
+	if (call)
+		err = apply_event_filter(call, buf);
+	mutex_unlock(&event_mutex);
+
 	free_page((unsigned long) buf);
 	if (err < 0)
 		return err;
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 0c7b75a8acc8..97daa8cf958d 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -637,17 +637,15 @@ static void append_filter_err(struct filter_parse_state *ps,
 	free_page((unsigned long) buf);
 }
 
+/* caller must hold event_mutex */
 void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
 {
-	struct event_filter *filter;
+	struct event_filter *filter = call->filter;
 
-	mutex_lock(&event_mutex);
-	filter = call->filter;
 	if (filter && filter->filter_string)
 		trace_seq_printf(s, "%s\n", filter->filter_string);
 	else
 		trace_seq_puts(s, "none\n");
-	mutex_unlock(&event_mutex);
 }
 
 void print_subsystem_event_filter(struct event_subsystem *system,
@@ -1841,23 +1839,22 @@ static int create_system_filter(struct event_subsystem *system,
 	return err;
 }
 
+/* caller must hold event_mutex */
 int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
 {
 	struct event_filter *filter;
-	int err = 0;
-
-	mutex_lock(&event_mutex);
+	int err;
 
 	if (!strcmp(strstrip(filter_string), "0")) {
 		filter_disable(call);
 		filter = call->filter;
 		if (!filter)
-			goto out_unlock;
+			return 0;
 		RCU_INIT_POINTER(call->filter, NULL);
 		/* Make sure the filter is not being used */
 		synchronize_sched();
 		__free_filter(filter);
-		goto out_unlock;
+		return 0;
 	}
 
 	err = create_filter(call, filter_string, true, &filter);
@@ -1884,8 +1881,6 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
 			__free_filter(tmp);
 		}
 	}
-out_unlock:
-	mutex_unlock(&event_mutex);
 
 	return err;
 }
-- 
cgit v1.2.3


From c5a44a1200c6eda2202434f25325e8ad19533fca Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 26 Jul 2013 19:25:43 +0200
Subject: tracing: Change f_start() to take event_mutex and verify i_private !=
 NULL

trace_format_open() and trace_format_seq_ops are racy, nothing
protects ftrace_event_call from trace_remove_event_call().

Change f_start() to take event_mutex and verify i_private != NULL,
change f_stop() to drop this lock.

This fixes nothing, but now we can change debugfs_remove("format")
callers to nullify ->i_private and fix the the problem.

Note: the usage of event_mutex is sub-optimal but simple, we can
change this later.

Link: http://lkml.kernel.org/r/20130726172543.GA3622@redhat.com

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1d7b6d03cd51..50dc8b2e5435 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -840,7 +840,7 @@ enum {
 
 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	struct ftrace_event_call *call = m->private;
+	struct ftrace_event_call *call = event_file_data(m->private);
 	struct list_head *common_head = &ftrace_common_fields;
 	struct list_head *head = trace_get_fields(call);
 	struct list_head *node = v;
@@ -872,7 +872,7 @@ static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 
 static int f_show(struct seq_file *m, void *v)
 {
-	struct ftrace_event_call *call = m->private;
+	struct ftrace_event_call *call = event_file_data(m->private);
 	struct ftrace_event_field *field;
 	const char *array_descriptor;
 
@@ -925,6 +925,11 @@ static void *f_start(struct seq_file *m, loff_t *pos)
 	void *p = (void *)FORMAT_HEADER;
 	loff_t l = 0;
 
+	/* ->stop() is called even if ->start() fails */
+	mutex_lock(&event_mutex);
+	if (!event_file_data(m->private))
+		return ERR_PTR(-ENODEV);
+
 	while (l < *pos && p)
 		p = f_next(m, p, &l);
 
@@ -933,6 +938,7 @@ static void *f_start(struct seq_file *m, loff_t *pos)
 
 static void f_stop(struct seq_file *m, void *p)
 {
+	mutex_unlock(&event_mutex);
 }
 
 static const struct seq_operations trace_format_seq_ops = {
@@ -944,7 +950,6 @@ static const struct seq_operations trace_format_seq_ops = {
 
 static int trace_format_open(struct inode *inode, struct file *file)
 {
-	struct ftrace_event_call *call = inode->i_private;
 	struct seq_file *m;
 	int ret;
 
@@ -953,7 +958,7 @@ static int trace_format_open(struct inode *inode, struct file *file)
 		return ret;
 
 	m = file->private_data;
-	m->private = call;
+	m->private = file;
 
 	return 0;
 }
-- 
cgit v1.2.3


From f6a84bdc75b5c11621dec58db73fe102cbaf40cc Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 26 Jul 2013 19:25:47 +0200
Subject: tracing: Introduce remove_event_file_dir()

Preparation for the next patch. Extract the common code from
remove_event_from_tracers() and __trace_remove_event_dirs()
into the new helper, remove_event_file_dir().

The patch looks more complicated than it actually is, it also
moves remove_subsystem() up to avoid the forward declaration.

Link: http://lkml.kernel.org/r/20130726172547.GA3629@redhat.com

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 47 ++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 50dc8b2e5435..05d647ecd01a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -409,11 +409,31 @@ static void put_system(struct ftrace_subsystem_dir *dir)
 	mutex_unlock(&event_mutex);
 }
 
+static void remove_subsystem(struct ftrace_subsystem_dir *dir)
+{
+	if (!dir)
+		return;
+
+	if (!--dir->nr_events) {
+		debugfs_remove_recursive(dir->entry);
+		list_del(&dir->list);
+		__put_system_dir(dir);
+	}
+}
+
 static void *event_file_data(struct file *filp)
 {
 	return ACCESS_ONCE(file_inode(filp)->i_private);
 }
 
+static void remove_event_file_dir(struct ftrace_event_file *file)
+{
+	list_del(&file->list);
+	debugfs_remove_recursive(file->dir);
+	remove_subsystem(file->system);
+	kmem_cache_free(file_cachep, file);
+}
+
 /*
  * Open and update trace_array ref count.
  * Must have the current trace_array passed to it.
@@ -1549,33 +1569,16 @@ event_create_dir(struct dentry *parent,
 	return 0;
 }
 
-static void remove_subsystem(struct ftrace_subsystem_dir *dir)
-{
-	if (!dir)
-		return;
-
-	if (!--dir->nr_events) {
-		debugfs_remove_recursive(dir->entry);
-		list_del(&dir->list);
-		__put_system_dir(dir);
-	}
-}
-
 static void remove_event_from_tracers(struct ftrace_event_call *call)
 {
 	struct ftrace_event_file *file;
 	struct trace_array *tr;
 
 	do_for_each_event_file_safe(tr, file) {
-
 		if (file->event_call != call)
 			continue;
 
-		list_del(&file->list);
-		debugfs_remove_recursive(file->dir);
-		remove_subsystem(file->system);
-		kmem_cache_free(file_cachep, file);
-
+		remove_event_file_dir(file);
 		/*
 		 * The do_for_each_event_file_safe() is
 		 * a double loop. After finding the call for this
@@ -2305,12 +2308,8 @@ __trace_remove_event_dirs(struct trace_array *tr)
 {
 	struct ftrace_event_file *file, *next;
 
-	list_for_each_entry_safe(file, next, &tr->events, list) {
-		list_del(&file->list);
-		debugfs_remove_recursive(file->dir);
-		remove_subsystem(file->system);
-		kmem_cache_free(file_cachep, file);
-	}
+	list_for_each_entry_safe(file, next, &tr->events, list)
+		remove_event_file_dir(file);
 }
 
 static void
-- 
cgit v1.2.3


From bf682c3159c4d298d1126a56793ed3f5e80395f7 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Sun, 28 Jul 2013 20:35:27 +0200
Subject: tracing: Change remove_event_file_dir() to clear
 "d_subdirs"->i_private

Change remove_event_file_dir() to clear ->i_private for every
file we are going to remove.

We need to check file->dir != NULL because event_create_dir()
can fail. debugfs_remove_recursive(NULL) is fine but the patch
moves it under the same check anyway for readability.

spin_lock(d_lock) and "d_inode != NULL" check are not needed
afaics, but I do not understand this code enough.

tracing_open_generic_file() and tracing_release_generic_file()
can go away, ftrace_enable_fops and ftrace_event_filter_fops()
use tracing_open_generic() but only to check tracing_disabled.

This fixes all races with event_remove() or instance_delete().
f_op->read/write/whatever can never use the freed file/call,
all event/* files were changed to check and use ->i_private
under event_mutex.

Note: this doesn't not fix other problems, event_remove() can
destroy the active ftrace_event_call, we need more changes but
those changes are completely orthogonal.

Link: http://lkml.kernel.org/r/20130728183527.GB16723@redhat.com

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 47 +++++++++++++++------------------------------
 1 file changed, 15 insertions(+), 32 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 05d647ecd01a..a67c913e2f9f 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -428,41 +428,25 @@ static void *event_file_data(struct file *filp)
 
 static void remove_event_file_dir(struct ftrace_event_file *file)
 {
+	struct dentry *dir = file->dir;
+	struct dentry *child;
+
+	if (dir) {
+		spin_lock(&dir->d_lock);	/* probably unneeded */
+		list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) {
+			if (child->d_inode)	/* probably unneeded */
+				child->d_inode->i_private = NULL;
+		}
+		spin_unlock(&dir->d_lock);
+
+		debugfs_remove_recursive(dir);
+	}
+
 	list_del(&file->list);
-	debugfs_remove_recursive(file->dir);
 	remove_subsystem(file->system);
 	kmem_cache_free(file_cachep, file);
 }
 
-/*
- * Open and update trace_array ref count.
- * Must have the current trace_array passed to it.
- */
-static int tracing_open_generic_file(struct inode *inode, struct file *filp)
-{
-	struct ftrace_event_file *file = inode->i_private;
-	struct trace_array *tr = file->tr;
-	int ret;
-
-	if (trace_array_get(tr) < 0)
-		return -ENODEV;
-
-	ret = tracing_open_generic(inode, filp);
-	if (ret < 0)
-		trace_array_put(tr);
-	return ret;
-}
-
-static int tracing_release_generic_file(struct inode *inode, struct file *filp)
-{
-	struct ftrace_event_file *file = inode->i_private;
-	struct trace_array *tr = file->tr;
-
-	trace_array_put(tr);
-
-	return 0;
-}
-
 /*
  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
  */
@@ -1281,10 +1265,9 @@ static const struct file_operations ftrace_set_event_fops = {
 };
 
 static const struct file_operations ftrace_enable_fops = {
-	.open = tracing_open_generic_file,
+	.open = tracing_open_generic,
 	.read = event_enable_read,
 	.write = event_enable_write,
-	.release = tracing_release_generic_file,
 	.llseek = default_llseek,
 };
 
-- 
cgit v1.2.3


From 1c80c43290ee576afe8d39ecc905fa3958a5858c Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Thu, 25 Jul 2013 20:22:00 -0400
Subject: ftrace: Consolidate some duplicate code for updating ftrace ops

When ftrace ops modifies the functions that it will trace, the update
to the function mcount callers may need to be modified. Consolidate
the two places that do the checks to see if an update is required
with a wrapper function for those checks.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8ce9eefc5bb4..92d3334de0c3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3384,6 +3384,12 @@ ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
 	return add_hash_entry(hash, ip);
 }
 
+static void ftrace_ops_update_code(struct ftrace_ops *ops)
+{
+	if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
+		ftrace_run_update_code(FTRACE_UPDATE_CALLS);
+}
+
 static int
 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 		unsigned long ip, int remove, int reset, int enable)
@@ -3426,9 +3432,8 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 
 	mutex_lock(&ftrace_lock);
 	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
-	if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
-	    && ftrace_enabled)
-		ftrace_run_update_code(FTRACE_UPDATE_CALLS);
+	if (!ret)
+		ftrace_ops_update_code(ops);
 
 	mutex_unlock(&ftrace_lock);
 
@@ -3655,9 +3660,8 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 		mutex_lock(&ftrace_lock);
 		ret = ftrace_hash_move(iter->ops, filter_hash,
 				       orig_hash, iter->hash);
-		if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
-		    && ftrace_enabled)
-			ftrace_run_update_code(FTRACE_UPDATE_CALLS);
+		if (!ret)
+			ftrace_ops_update_code(iter->ops);
 
 		mutex_unlock(&ftrace_lock);
 	}
-- 
cgit v1.2.3


From 8c4f3c3fa9681dc549cd35419b259496082fef8b Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Tue, 30 Jul 2013 00:04:32 -0400
Subject: ftrace: Check module functions being traced on reload
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

There's been a nasty bug that would show up and not give much info.
The bug displayed the following warning:

 WARNING: at kernel/trace/ftrace.c:1529 __ftrace_hash_rec_update+0x1e3/0x230()
 Pid: 20903, comm: bash Tainted: G           O 3.6.11+ #38405.trunk
 Call Trace:
  [<ffffffff8103e5ff>] warn_slowpath_common+0x7f/0xc0
  [<ffffffff8103e65a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff810c2ee3>] __ftrace_hash_rec_update+0x1e3/0x230
  [<ffffffff810c4f28>] ftrace_hash_move+0x28/0x1d0
  [<ffffffff811401cc>] ? kfree+0x2c/0x110
  [<ffffffff810c68ee>] ftrace_regex_release+0x8e/0x150
  [<ffffffff81149f1e>] __fput+0xae/0x220
  [<ffffffff8114a09e>] ____fput+0xe/0x10
  [<ffffffff8105fa22>] task_work_run+0x72/0x90
  [<ffffffff810028ec>] do_notify_resume+0x6c/0xc0
  [<ffffffff8126596e>] ? trace_hardirqs_on_thunk+0x3a/0x3c
  [<ffffffff815c0f88>] int_signal+0x12/0x17
 ---[ end trace 793179526ee09b2c ]---

It was finally narrowed down to unloading a module that was being traced.

It was actually more than that. When functions are being traced, there's
a table of all functions that have a ref count of the number of active
tracers attached to that function. When a function trace callback is
registered to a function, the function's record ref count is incremented.
When it is unregistered, the function's record ref count is decremented.
If an inconsistency is detected (ref count goes below zero) the above
warning is shown and the function tracing is permanently disabled until
reboot.

The ftrace callback ops holds a hash of functions that it filters on
(and/or filters off). If the hash is empty, the default means to filter
all functions (for the filter_hash) or to disable no functions (for the
notrace_hash).

When a module is unloaded, it frees the function records that represent
the module functions. These records exist on their own pages, that is
function records for one module will not exist on the same page as
function records for other modules or even the core kernel.

Now when a module unloads, the records that represents its functions are
freed. When the module is loaded again, the records are recreated with
a default ref count of zero (unless there's a callback that traces all
functions, then they will also be traced, and the ref count will be
incremented).

The problem is that if an ftrace callback hash includes functions of the
module being unloaded, those hash entries will not be removed. If the
module is reloaded in the same location, the hash entries still point
to the functions of the module but the module's ref counts do not reflect
that.

With the help of Steve and Joern, we found a reproducer:

 Using uinput module and uinput_release function.

 cd /sys/kernel/debug/tracing
 modprobe uinput
 echo uinput_release > set_ftrace_filter
 echo function > current_tracer
 rmmod uinput
 modprobe uinput
 # check /proc/modules to see if loaded in same addr, otherwise try again
 echo nop > current_tracer

 [BOOM]

The above loads the uinput module, which creates a table of functions that
can be traced within the module.

We add uinput_release to the filter_hash to trace just that function.

Enable function tracincg, which increments the ref count of the record
associated to uinput_release.

Remove uinput, which frees the records including the one that represents
uinput_release.

Load the uinput module again (and make sure it's at the same address).
This recreates the function records all with a ref count of zero,
including uinput_release.

Disable function tracing, which will decrement the ref count for uinput_release
which is now zero because of the module removal and reload, and we have
a mismatch (below zero ref count).

The solution is to check all currently tracing ftrace callbacks to see if any
are tracing any of the module's functions when a module is loaded (it already does
that with callbacks that trace all functions). If a callback happens to have
a module function being traced, it increments that records ref count and starts
tracing that function.

There may be a strange side effect with this, where tracing module functions
on unload and then reloading a new module may have that new module's functions
being traced. This may be something that confuses the user, but it's not
a big deal. Another approach is to disable all callback hashes on module unload,
but this leaves some ftrace callbacks that may not be registered, but can
still have hashes tracing the module's function where ftrace doesn't know about
it. That situation can cause the same bug. This solution solves that case too.
Another benefit of this solution, is it is possible to trace a module's
function on unload and load.

Link: http://lkml.kernel.org/r/20130705142629.GA325@redhat.com

Reported-by: Jörn Engel <joern@logfs.org>
Reported-by: Dave Jones <davej@redhat.com>
Reported-by: Steve Hodgson <steve@purestorage.com>
Tested-by: Steve Hodgson <steve@purestorage.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 71 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 62 insertions(+), 9 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 92d3334de0c3..a6d098c6df3f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2169,12 +2169,57 @@ static cycle_t		ftrace_update_time;
 static unsigned long	ftrace_update_cnt;
 unsigned long		ftrace_update_tot_cnt;
 
-static int ops_traces_mod(struct ftrace_ops *ops)
+static inline int ops_traces_mod(struct ftrace_ops *ops)
 {
-	struct ftrace_hash *hash;
+	/*
+	 * Filter_hash being empty will default to trace module.
+	 * But notrace hash requires a test of individual module functions.
+	 */
+	return ftrace_hash_empty(ops->filter_hash) &&
+		ftrace_hash_empty(ops->notrace_hash);
+}
+
+/*
+ * Check if the current ops references the record.
+ *
+ * If the ops traces all functions, then it was already accounted for.
+ * If the ops does not trace the current record function, skip it.
+ * If the ops ignores the function via notrace filter, skip it.
+ */
+static inline bool
+ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
+{
+	/* If ops isn't enabled, ignore it */
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return 0;
+
+	/* If ops traces all mods, we already accounted for it */
+	if (ops_traces_mod(ops))
+		return 0;
+
+	/* The function must be in the filter */
+	if (!ftrace_hash_empty(ops->filter_hash) &&
+	    !ftrace_lookup_ip(ops->filter_hash, rec->ip))
+		return 0;
 
-	hash = ops->filter_hash;
-	return ftrace_hash_empty(hash);
+	/* If in notrace hash, we ignore it too */
+	if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
+		return 0;
+
+	return 1;
+}
+
+static int referenced_filters(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *ops;
+	int cnt = 0;
+
+	for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
+		if (ops_references_rec(ops, rec))
+		    cnt++;
+	}
+
+	return cnt;
 }
 
 static int ftrace_update_code(struct module *mod)
@@ -2183,6 +2228,7 @@ static int ftrace_update_code(struct module *mod)
 	struct dyn_ftrace *p;
 	cycle_t start, stop;
 	unsigned long ref = 0;
+	bool test = false;
 	int i;
 
 	/*
@@ -2196,9 +2242,12 @@ static int ftrace_update_code(struct module *mod)
 
 		for (ops = ftrace_ops_list;
 		     ops != &ftrace_list_end; ops = ops->next) {
-			if (ops->flags & FTRACE_OPS_FL_ENABLED &&
-			    ops_traces_mod(ops))
-				ref++;
+			if (ops->flags & FTRACE_OPS_FL_ENABLED) {
+				if (ops_traces_mod(ops))
+					ref++;
+				else
+					test = true;
+			}
 		}
 	}
 
@@ -2208,12 +2257,16 @@ static int ftrace_update_code(struct module *mod)
 	for (pg = ftrace_new_pgs; pg; pg = pg->next) {
 
 		for (i = 0; i < pg->index; i++) {
+			int cnt = ref;
+
 			/* If something went wrong, bail without enabling anything */
 			if (unlikely(ftrace_disabled))
 				return -1;
 
 			p = &pg->records[i];
-			p->flags = ref;
+			if (test)
+				cnt += referenced_filters(p);
+			p->flags = cnt;
 
 			/*
 			 * Do the initial record conversion from mcount jump
@@ -2233,7 +2286,7 @@ static int ftrace_update_code(struct module *mod)
 			 * conversion puts the module to the correct state, thus
 			 * passing the ftrace_make_call check.
 			 */
-			if (ftrace_start_up && ref) {
+			if (ftrace_start_up && cnt) {
 				int failed = __ftrace_replace_code(p, 1);
 				if (failed)
 					ftrace_bug(failed, p->ip);
-- 
cgit v1.2.3


From 2816c551c796ec14620325b2c9ed75b9979d3125 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 29 Jul 2013 19:50:33 +0200
Subject: tracing: trace_remove_event_call() should fail if call/file is in use

Change trace_remove_event_call(call) to return the error if this
call is active. This is what the callers assume but can't verify
outside of the tracing locks. Both trace_kprobe.c/trace_uprobe.c
need the additional changes, unregister_trace_probe() should abort
if trace_remove_event_call() fails.

The caller is going to free this call/file so we must ensure that
nobody can use them after trace_remove_event_call() succeeds.
debugfs should be fine after the previous changes and event_remove()
does TRACE_REG_UNREGISTER, but still there are 2 reasons why we need
the additional checks:

- There could be a perf_event(s) attached to this tp_event, so the
  patch checks ->perf_refcount.

- TRACE_REG_UNREGISTER can be suppressed by FTRACE_EVENT_FL_SOFT_MODE,
  so we simply check FTRACE_EVENT_FL_ENABLED protected by event_mutex.

Link: http://lkml.kernel.org/r/20130729175033.GB26284@redhat.com

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a67c913e2f9f..ec04836273c0 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1713,16 +1713,47 @@ static void __trace_remove_event_call(struct ftrace_event_call *call)
 	destroy_preds(call);
 }
 
+static int probe_remove_event_call(struct ftrace_event_call *call)
+{
+	struct trace_array *tr;
+	struct ftrace_event_file *file;
+
+#ifdef CONFIG_PERF_EVENTS
+	if (call->perf_refcount)
+		return -EBUSY;
+#endif
+	do_for_each_event_file(tr, file) {
+		if (file->event_call != call)
+			continue;
+		/*
+		 * We can't rely on ftrace_event_enable_disable(enable => 0)
+		 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
+		 * TRACE_REG_UNREGISTER.
+		 */
+		if (file->flags & FTRACE_EVENT_FL_ENABLED)
+			return -EBUSY;
+		break;
+	} while_for_each_event_file();
+
+	__trace_remove_event_call(call);
+
+	return 0;
+}
+
 /* Remove an event_call */
-void trace_remove_event_call(struct ftrace_event_call *call)
+int trace_remove_event_call(struct ftrace_event_call *call)
 {
+	int ret;
+
 	mutex_lock(&trace_types_lock);
 	mutex_lock(&event_mutex);
 	down_write(&trace_event_sem);
-	__trace_remove_event_call(call);
+	ret = probe_remove_event_call(call);
 	up_write(&trace_event_sem);
 	mutex_unlock(&event_mutex);
 	mutex_unlock(&trace_types_lock);
+
+	return ret;
 }
 
 #define for_each_event(event, start, end)			\
-- 
cgit v1.2.3


From 2ba64035d0ca966fd189bc3e0826343fc81bf482 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 31 Jul 2013 13:16:22 -0400
Subject: tracing: Add comment to describe special break case in
 probe_remove_event_call()

The "break" used in the do_for_each_event_file() is used as an optimization
as the loop is really a double loop. The loop searches all event files
for each trace_array. There's only one matching event file per trace_array
and after we find the event file for the trace_array, the break is used
to jump to the next trace_array and start the search there.

As this is not a standard way of using "break" in C code, it requires
a comment right before the break to let people know what is going on.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ec04836273c0..29a7ebcfb426 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1732,6 +1732,12 @@ static int probe_remove_event_call(struct ftrace_event_call *call)
 		 */
 		if (file->flags & FTRACE_EVENT_FL_ENABLED)
 			return -EBUSY;
+		/*
+		 * The do_for_each_event_file_safe() is
+		 * a double loop. After finding the call for this
+		 * trace_array, we use break to jump to the next
+		 * trace_array.
+		 */
 		break;
 	} while_for_each_event_file();
 
-- 
cgit v1.2.3


From 40c32592668b727cbfcf7b1c0567f581bd62a5e4 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 3 Jul 2013 23:33:50 -0400
Subject: tracing/kprobes: Fail to unregister if probe event files are in use

When a probe is being removed, it cleans up the event files that correspond
to the probe. But there is a race between writing to one of these files
and deleting the probe. This is especially true for the "enable" file.

	CPU 0				CPU 1
	-----				-----

				  fd = open("enable",O_WRONLY);

  probes_open()
  release_all_trace_probes()
  unregister_trace_probe()
  if (trace_probe_is_enabled(tp))
	return -EBUSY

				   write(fd, "1", 1)
				   __ftrace_set_clr_event()
				   call->class->reg()
				    (kprobe_register)
				     enable_trace_probe(tp)

  __unregister_trace_probe(tp);
  list_del(&tp->list)
  unregister_probe_event(tp) <-- fails!
  free_trace_probe(tp)

				   write(fd, "0", 1)
				   __ftrace_set_clr_event()
				   call->class->unreg
				    (kprobe_register)
				    disable_trace_probe(tp) <-- BOOM!

A test program was written that used two threads to simulate the
above scenario adding a nanosleep() interval to change the timings
and after several thousand runs, it was able to trigger this bug
and crash:

BUG: unable to handle kernel paging request at 00000005000000f9
IP: [<ffffffff810dee70>] probes_open+0x3b/0xa7
PGD 7808a067 PUD 0
Oops: 0000 [#1] PREEMPT SMP
Dumping ftrace buffer:
---------------------------------
Modules linked in: ipt_MASQUERADE sunrpc ip6t_REJECT nf_conntrack_ipv6
CPU: 1 PID: 2070 Comm: test-kprobe-rem Not tainted 3.11.0-rc3-test+ #47
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007
task: ffff880077756440 ti: ffff880076e52000 task.ti: ffff880076e52000
RIP: 0010:[<ffffffff810dee70>]  [<ffffffff810dee70>] probes_open+0x3b/0xa7
RSP: 0018:ffff880076e53c38  EFLAGS: 00010203
RAX: 0000000500000001 RBX: ffff88007844f440 RCX: 0000000000000003
RDX: 0000000000000003 RSI: 0000000000000003 RDI: ffff880076e52000
RBP: ffff880076e53c58 R08: ffff880076e53bd8 R09: 0000000000000000
R10: ffff880077756440 R11: 0000000000000006 R12: ffffffff810dee35
R13: ffff880079250418 R14: 0000000000000000 R15: ffff88007844f450
FS:  00007f87a276f700(0000) GS:ffff88007d480000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000005000000f9 CR3: 0000000077262000 CR4: 00000000000007e0
Stack:
 ffff880076e53c58 ffffffff81219ea0 ffff88007844f440 ffffffff810dee35
 ffff880076e53ca8 ffffffff81130f78 ffff8800772986c0 ffff8800796f93a0
 ffffffff81d1b5d8 ffff880076e53e04 0000000000000000 ffff88007844f440
Call Trace:
 [<ffffffff81219ea0>] ? security_file_open+0x2c/0x30
 [<ffffffff810dee35>] ? unregister_trace_probe+0x4b/0x4b
 [<ffffffff81130f78>] do_dentry_open+0x162/0x226
 [<ffffffff81131186>] finish_open+0x46/0x54
 [<ffffffff8113f30b>] do_last+0x7f6/0x996
 [<ffffffff8113cc6f>] ? inode_permission+0x42/0x44
 [<ffffffff8113f6dd>] path_openat+0x232/0x496
 [<ffffffff8113fc30>] do_filp_open+0x3a/0x8a
 [<ffffffff8114ab32>] ? __alloc_fd+0x168/0x17a
 [<ffffffff81131f4e>] do_sys_open+0x70/0x102
 [<ffffffff8108f06e>] ? trace_hardirqs_on_caller+0x160/0x197
 [<ffffffff81131ffe>] SyS_open+0x1e/0x20
 [<ffffffff81522742>] system_call_fastpath+0x16/0x1b
Code: e5 41 54 53 48 89 f3 48 83 ec 10 48 23 56 78 48 39 c2 75 6c 31 f6 48 c7
RIP  [<ffffffff810dee70>] probes_open+0x3b/0xa7
 RSP <ffff880076e53c38>
CR2: 00000005000000f9
---[ end trace 35f17d68fc569897 ]---

The unregister_trace_probe() must be done first, and if it fails it must
fail the removal of the kprobe.

Several changes have already been made by Oleg Nesterov and Masami Hiramatsu
to allow moving the unregister_probe_event() before the removal of
the probe and exit the function if it fails. This prevents the tp
structure from being used after it is freed.

Link: http://lkml.kernel.org/r/20130704034038.819592356@goodmis.org

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 3811487e7a7a..243f6834d026 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -95,7 +95,7 @@ static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp)
 }
 
 static int register_probe_event(struct trace_probe *tp);
-static void unregister_probe_event(struct trace_probe *tp);
+static int unregister_probe_event(struct trace_probe *tp);
 
 static DEFINE_MUTEX(probe_lock);
 static LIST_HEAD(probe_list);
@@ -351,9 +351,12 @@ static int unregister_trace_probe(struct trace_probe *tp)
 	if (trace_probe_is_enabled(tp))
 		return -EBUSY;
 
+	/* Will fail if probe is being used by ftrace or perf */
+	if (unregister_probe_event(tp))
+		return -EBUSY;
+
 	__unregister_trace_probe(tp);
 	list_del(&tp->list);
-	unregister_probe_event(tp);
 
 	return 0;
 }
@@ -632,7 +635,9 @@ static int release_all_trace_probes(void)
 	/* TODO: Use batch unregistration */
 	while (!list_empty(&probe_list)) {
 		tp = list_entry(probe_list.next, struct trace_probe, list);
-		unregister_trace_probe(tp);
+		ret = unregister_trace_probe(tp);
+		if (ret)
+			goto end;
 		free_trace_probe(tp);
 	}
 
@@ -1247,11 +1252,15 @@ static int register_probe_event(struct trace_probe *tp)
 	return ret;
 }
 
-static void unregister_probe_event(struct trace_probe *tp)
+static int unregister_probe_event(struct trace_probe *tp)
 {
+	int ret;
+
 	/* tp->event is unregistered in trace_remove_event_call() */
-	trace_remove_event_call(&tp->call);
-	kfree(tp->call.print_fmt);
+	ret = trace_remove_event_call(&tp->call);
+	if (!ret)
+		kfree(tp->call.print_fmt);
+	return ret;
 }
 
 /* Make a debugfs interface for controlling probe points */
-- 
cgit v1.2.3


From c6c2401d8bbaf9edc189b4c35a8cb2780b8b988e Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 3 Jul 2013 23:33:51 -0400
Subject: tracing/uprobes: Fail to unregister if probe event files are in use

Uprobes suffer the same problem that kprobes have. There's a race between
writing to the "enable" file and removing the probe. The probe checks for
it being in use and if it is not, goes about deleting the probe and the
event that represents it. But the problem with that is, after it checks
if it is in use it can be enabled, and the deletion of the event (access
to the probe) will fail, as it is in use. But the uprobe will still be
deleted. This is a problem as the event can reference the uprobe that
was deleted.

The fix is to remove the event first, and check to make sure the event
removal succeeds. Then it is safe to remove the probe.

When the event exists, either ftrace or perf can enable the probe and
prevent the event from being removed.

Link: http://lkml.kernel.org/r/20130704034038.991525256@goodmis.org

Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_uprobe.c | 51 +++++++++++++++++++++++++++++++++------------
 1 file changed, 38 insertions(+), 13 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index a23d2d71188e..272261b5f94f 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -70,7 +70,7 @@ struct trace_uprobe {
 	(sizeof(struct probe_arg) * (n)))
 
 static int register_uprobe_event(struct trace_uprobe *tu);
-static void unregister_uprobe_event(struct trace_uprobe *tu);
+static int unregister_uprobe_event(struct trace_uprobe *tu);
 
 static DEFINE_MUTEX(uprobe_lock);
 static LIST_HEAD(uprobe_list);
@@ -164,11 +164,17 @@ static struct trace_uprobe *find_probe_event(const char *event, const char *grou
 }
 
 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
-static void unregister_trace_uprobe(struct trace_uprobe *tu)
+static int unregister_trace_uprobe(struct trace_uprobe *tu)
 {
+	int ret;
+
+	ret = unregister_uprobe_event(tu);
+	if (ret)
+		return ret;
+
 	list_del(&tu->list);
-	unregister_uprobe_event(tu);
 	free_trace_uprobe(tu);
+	return 0;
 }
 
 /* Register a trace_uprobe and probe_event */
@@ -181,9 +187,12 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 
 	/* register as an event */
 	old_tp = find_probe_event(tu->call.name, tu->call.class->system);
-	if (old_tp)
+	if (old_tp) {
 		/* delete old event */
-		unregister_trace_uprobe(old_tp);
+		ret = unregister_trace_uprobe(old_tp);
+		if (ret)
+			goto end;
+	}
 
 	ret = register_uprobe_event(tu);
 	if (ret) {
@@ -256,6 +265,8 @@ static int create_trace_uprobe(int argc, char **argv)
 		group = UPROBE_EVENT_SYSTEM;
 
 	if (is_delete) {
+		int ret;
+
 		if (!event) {
 			pr_info("Delete command needs an event name.\n");
 			return -EINVAL;
@@ -269,9 +280,9 @@ static int create_trace_uprobe(int argc, char **argv)
 			return -ENOENT;
 		}
 		/* delete an event */
-		unregister_trace_uprobe(tu);
+		ret = unregister_trace_uprobe(tu);
 		mutex_unlock(&uprobe_lock);
-		return 0;
+		return ret;
 	}
 
 	if (argc < 2) {
@@ -408,16 +419,20 @@ fail_address_parse:
 	return ret;
 }
 
-static void cleanup_all_probes(void)
+static int cleanup_all_probes(void)
 {
 	struct trace_uprobe *tu;
+	int ret = 0;
 
 	mutex_lock(&uprobe_lock);
 	while (!list_empty(&uprobe_list)) {
 		tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
-		unregister_trace_uprobe(tu);
+		ret = unregister_trace_uprobe(tu);
+		if (ret)
+			break;
 	}
 	mutex_unlock(&uprobe_lock);
+	return ret;
 }
 
 /* Probes listing interfaces */
@@ -462,8 +477,13 @@ static const struct seq_operations probes_seq_op = {
 
 static int probes_open(struct inode *inode, struct file *file)
 {
-	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
-		cleanup_all_probes();
+	int ret;
+
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		ret = cleanup_all_probes();
+		if (ret)
+			return ret;
+	}
 
 	return seq_open(file, &probes_seq_op);
 }
@@ -968,12 +988,17 @@ static int register_uprobe_event(struct trace_uprobe *tu)
 	return ret;
 }
 
-static void unregister_uprobe_event(struct trace_uprobe *tu)
+static int unregister_uprobe_event(struct trace_uprobe *tu)
 {
+	int ret;
+
 	/* tu->event is unregistered in trace_remove_event_call() */
-	trace_remove_event_call(&tu->call);
+	ret = trace_remove_event_call(&tu->call);
+	if (ret)
+		return ret;
 	kfree(tu->call.print_fmt);
 	tu->call.print_fmt = NULL;
+	return 0;
 }
 
 /* Make a trace interface for controling probe points */
-- 
cgit v1.2.3


From ed5467da0e369e65b247b99eb6403cb79172bcda Mon Sep 17 00:00:00 2001
From: Andrew Vagin <avagin@openvz.org>
Date: Fri, 2 Aug 2013 21:16:43 +0400
Subject: tracing: Fix fields of struct trace_iterator that are zeroed by
 mistake

tracing_read_pipe zeros all fields bellow "seq". The declaration contains
a comment about that, but it doesn't help.

The first field is "snapshot", it's true when current open file is
snapshot. Looks obvious, that it should not be zeroed.

The second field is "started". It was converted from cpumask_t to
cpumask_var_t (v2.6.28-4983-g4462344), in other words it was
converted from cpumask to pointer on cpumask.

Currently the reference on "started" memory is lost after the first read
from tracing_read_pipe and a proper object will never be freed.

The "started" is never dereferenced for trace_pipe, because trace_pipe
can't have the TRACE_FILE_ANNOTATE options.

Link: http://lkml.kernel.org/r/1375463803-3085183-1-git-send-email-avagin@openvz.org

Cc: stable@vger.kernel.org # 2.6.30
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 882ec1dd1515..f5b35a5e852f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4151,6 +4151,7 @@ waitagain:
 	memset(&iter->seq, 0,
 	       sizeof(struct trace_iterator) -
 	       offsetof(struct trace_iterator, seq));
+	cpumask_clear(iter->started);
 	iter->pos = -1;
 
 	trace_event_read_lock();
-- 
cgit v1.2.3


From 711e124379e0f889e40e2f01d7f5d61936d3cd23 Mon Sep 17 00:00:00 2001
From: Alexander Z Lam <azl@google.com>
Date: Fri, 2 Aug 2013 18:36:15 -0700
Subject: tracing: Make TRACE_ITER_STOP_ON_FREE stop the correct buffer

Releasing the free_buffer file in an instance causes the global buffer
to be stopped when TRACE_ITER_STOP_ON_FREE is enabled. Operate on the
correct buffer.

Link: http://lkml.kernel.org/r/1375493777-17261-1-git-send-email-azl@google.com

Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f5b35a5e852f..531c9e69d0b3 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4469,7 +4469,7 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp)
 
 	/* disable tracing ? */
 	if (trace_flags & TRACE_ITER_STOP_ON_FREE)
-		tracing_off();
+		tracer_tracing_off(tr);
 	/* resize the ring buffer to 0 */
 	tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
 
-- 
cgit v1.2.3


From 9457158bbc0ee04ecef76862d73eecd8076e9c7b Mon Sep 17 00:00:00 2001
From: Alexander Z Lam <azl@google.com>
Date: Fri, 2 Aug 2013 18:36:16 -0700
Subject: tracing: Fix reset of time stamps during trace_clock changes

Fixed two issues with changing the timestamp clock with trace_clock:

 - The global buffer was reset on instance clock changes. Change this to pass
   the correct per-instance buffer
 - ftrace_now() is used to set buf->time_start in tracing_reset_online_cpus().
   This was incorrect because ftrace_now() used the global buffer's clock to
   return the current time. Change this to use buffer_ftrace_now() which
   returns the current time for the correct per-instance buffer.

Also removed tracing_reset_current() because it is not used anywhere

Link: http://lkml.kernel.org/r/1375493777-17261-2-git-send-email-azl@google.com

Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 531c9e69d0b3..496f94d57698 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -243,20 +243,25 @@ int filter_current_check_discard(struct ring_buffer *buffer,
 }
 EXPORT_SYMBOL_GPL(filter_current_check_discard);
 
-cycle_t ftrace_now(int cpu)
+cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
 {
 	u64 ts;
 
 	/* Early boot up does not have a buffer yet */
-	if (!global_trace.trace_buffer.buffer)
+	if (!buf->buffer)
 		return trace_clock_local();
 
-	ts = ring_buffer_time_stamp(global_trace.trace_buffer.buffer, cpu);
-	ring_buffer_normalize_time_stamp(global_trace.trace_buffer.buffer, cpu, &ts);
+	ts = ring_buffer_time_stamp(buf->buffer, cpu);
+	ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
 
 	return ts;
 }
 
+cycle_t ftrace_now(int cpu)
+{
+	return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
+}
+
 /**
  * tracing_is_enabled - Show if global_trace has been disabled
  *
@@ -1211,7 +1216,7 @@ void tracing_reset_online_cpus(struct trace_buffer *buf)
 	/* Make sure all commits have finished */
 	synchronize_sched();
 
-	buf->time_start = ftrace_now(buf->cpu);
+	buf->time_start = buffer_ftrace_now(buf, buf->cpu);
 
 	for_each_online_cpu(cpu)
 		ring_buffer_reset_cpu(buffer, cpu);
@@ -1219,11 +1224,6 @@ void tracing_reset_online_cpus(struct trace_buffer *buf)
 	ring_buffer_record_enable(buffer);
 }
 
-void tracing_reset_current(int cpu)
-{
-	tracing_reset(&global_trace.trace_buffer, cpu);
-}
-
 /* Must have trace_types_lock held */
 void tracing_reset_all_online_cpus(void)
 {
@@ -4634,12 +4634,12 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
 	 * New clock may not be consistent with the previous clock.
 	 * Reset the buffer so that it doesn't have incomparable timestamps.
 	 */
-	tracing_reset_online_cpus(&global_trace.trace_buffer);
+	tracing_reset_online_cpus(&tr->trace_buffer);
 
 #ifdef CONFIG_TRACER_MAX_TRACE
 	if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
 		ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
-	tracing_reset_online_cpus(&global_trace.max_buffer);
+	tracing_reset_online_cpus(&tr->max_buffer);
 #endif
 
 	mutex_unlock(&trace_types_lock);
-- 
cgit v1.2.3