From 827e609b4581282b98bdf7666f6e93ff1bd1a63e Mon Sep 17 00:00:00 2001 From: Harvey Harrison Date: Wed, 28 May 2008 12:49:56 -0500 Subject: kgdb: use common ascii helpers and put_unaligned_be32 helper Signed-off-by: Harvey Harrison Signed-off-by: Andrew Morton Signed-off-by: Jason Wessel --- kernel/kgdb.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 14787de568b3..79e3c90113c2 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -52,6 +52,7 @@ #include #include #include +#include static int kgdb_break_asap; @@ -227,8 +228,6 @@ void __weak kgdb_disable_hw_debug(struct pt_regs *regs) * GDB remote protocol parser: */ -static const char hexchars[] = "0123456789abcdef"; - static int hex(char ch) { if ((ch >= 'a') && (ch <= 'f')) @@ -316,8 +315,8 @@ static void put_packet(char *buffer) } kgdb_io_ops->write_char('#'); - kgdb_io_ops->write_char(hexchars[checksum >> 4]); - kgdb_io_ops->write_char(hexchars[checksum & 0xf]); + kgdb_io_ops->write_char(hex_asc_hi(checksum)); + kgdb_io_ops->write_char(hex_asc_lo(checksum)); if (kgdb_io_ops->flush) kgdb_io_ops->flush(); @@ -478,8 +477,8 @@ static void error_packet(char *pkt, int error) { error = -error; pkt[0] = 'E'; - pkt[1] = hexchars[(error / 10)]; - pkt[2] = hexchars[(error % 10)]; + pkt[1] = hex_asc[(error / 10)]; + pkt[2] = hex_asc[(error % 10)]; pkt[3] = '\0'; } @@ -510,10 +509,7 @@ static void int_to_threadref(unsigned char *id, int value) scan = (unsigned char *)id; while (i--) *scan++ = 0; - *scan++ = (value >> 24) & 0xff; - *scan++ = (value >> 16) & 0xff; - *scan++ = (value >> 8) & 0xff; - *scan++ = (value & 0xff); + put_unaligned_be32(value, scan); } static struct task_struct *getthread(struct pt_regs *regs, int tid) -- cgit v1.2.3 From ca05a99a54db1db5bca72eccb5866d2a86f8517f Mon Sep 17 00:00:00 2001 From: "Andrew G. Morgan" Date: Tue, 27 May 2008 22:05:17 -0700 Subject: capabilities: remain source compatible with 32-bit raw legacy capability support. Source code out there hard-codes a notion of what the _LINUX_CAPABILITY_VERSION #define means in terms of the semantics of the raw capability system calls capget() and capset(). Its unfortunate, but true. Since the confusing header file has been in a released kernel, there is software that is erroneously using 64-bit capabilities with the semantics of 32-bit compatibilities. These recently compiled programs may suffer corruption of their memory when sys_getcap() overwrites more memory than they are coded to expect, and the raising of added capabilities when using sys_capset(). As such, this patch does a number of things to clean up the situation for all. It 1. forces the _LINUX_CAPABILITY_VERSION define to always retain its legacy value. 2. adopts a new #define strategy for the kernel's internal implementation of the preferred magic. 3. deprecates v2 capability magic in favor of a new (v3) magic number. The functionality of v3 is entirely equivalent to v2, the only difference being that the v2 magic causes the kernel to log a "deprecated" warning so the admin can find applications that may be using v2 inappropriately. [User space code continues to be encouraged to use the libcap API which protects the application from details like this. libcap-2.10 is the first to support v3 capabilities.] Fixes issue reported in https://bugzilla.redhat.com/show_bug.cgi?id=447518. Thanks to Bojan Smojver for the report. [akpm@linux-foundation.org: s/depreciate/deprecate/g] [akpm@linux-foundation.org: be robust about put_user size] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew G. Morgan Cc: Serge E. Hallyn Cc: Bojan Smojver Cc: stable@kernel.org Signed-off-by: Andrew Morton Signed-off-by: Chris Wright --- kernel/capability.c | 111 ++++++++++++++++++++++++++++++++++------------------ 1 file changed, 73 insertions(+), 38 deletions(-) (limited to 'kernel') diff --git a/kernel/capability.c b/kernel/capability.c index 39e8193b41ea..cfbe44299488 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -52,6 +52,69 @@ static void warn_legacy_capability_use(void) } } +/* + * Version 2 capabilities worked fine, but the linux/capability.h file + * that accompanied their introduction encouraged their use without + * the necessary user-space source code changes. As such, we have + * created a version 3 with equivalent functionality to version 2, but + * with a header change to protect legacy source code from using + * version 2 when it wanted to use version 1. If your system has code + * that trips the following warning, it is using version 2 specific + * capabilities and may be doing so insecurely. + * + * The remedy is to either upgrade your version of libcap (to 2.10+, + * if the application is linked against it), or recompile your + * application with modern kernel headers and this warning will go + * away. + */ + +static void warn_deprecated_v2(void) +{ + static int warned; + + if (!warned) { + char name[sizeof(current->comm)]; + + printk(KERN_INFO "warning: `%s' uses deprecated v2" + " capabilities in a way that may be insecure.\n", + get_task_comm(name, current)); + warned = 1; + } +} + +/* + * Version check. Return the number of u32s in each capability flag + * array, or a negative value on error. + */ +static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy) +{ + __u32 version; + + if (get_user(version, &header->version)) + return -EFAULT; + + switch (version) { + case _LINUX_CAPABILITY_VERSION_1: + warn_legacy_capability_use(); + *tocopy = _LINUX_CAPABILITY_U32S_1; + break; + case _LINUX_CAPABILITY_VERSION_2: + warn_deprecated_v2(); + /* + * fall through - v3 is otherwise equivalent to v2. + */ + case _LINUX_CAPABILITY_VERSION_3: + *tocopy = _LINUX_CAPABILITY_U32S_3; + break; + default: + if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version)) + return -EFAULT; + return -EINVAL; + } + + return 0; +} + /* * For sys_getproccap() and sys_setproccap(), any of the three * capability set pointers may be NULL -- indicating that that set is @@ -71,27 +134,13 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr) { int ret = 0; pid_t pid; - __u32 version; struct task_struct *target; unsigned tocopy; kernel_cap_t pE, pI, pP; - if (get_user(version, &header->version)) - return -EFAULT; - - switch (version) { - case _LINUX_CAPABILITY_VERSION_1: - warn_legacy_capability_use(); - tocopy = _LINUX_CAPABILITY_U32S_1; - break; - case _LINUX_CAPABILITY_VERSION_2: - tocopy = _LINUX_CAPABILITY_U32S_2; - break; - default: - if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) - return -EFAULT; - return -EINVAL; - } + ret = cap_validate_magic(header, &tocopy); + if (ret != 0) + return ret; if (get_user(pid, &header->pid)) return -EFAULT; @@ -118,7 +167,7 @@ out: spin_unlock(&task_capability_lock); if (!ret) { - struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S]; + struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; unsigned i; for (i = 0; i < tocopy; i++) { @@ -128,7 +177,7 @@ out: } /* - * Note, in the case, tocopy < _LINUX_CAPABILITY_U32S, + * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S, * we silently drop the upper capabilities here. This * has the effect of making older libcap * implementations implicitly drop upper capability @@ -240,30 +289,16 @@ static inline int cap_set_all(kernel_cap_t *effective, */ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data) { - struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S]; + struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; unsigned i, tocopy; kernel_cap_t inheritable, permitted, effective; - __u32 version; struct task_struct *target; int ret; pid_t pid; - if (get_user(version, &header->version)) - return -EFAULT; - - switch (version) { - case _LINUX_CAPABILITY_VERSION_1: - warn_legacy_capability_use(); - tocopy = _LINUX_CAPABILITY_U32S_1; - break; - case _LINUX_CAPABILITY_VERSION_2: - tocopy = _LINUX_CAPABILITY_U32S_2; - break; - default: - if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) - return -EFAULT; - return -EINVAL; - } + ret = cap_validate_magic(header, &tocopy); + if (ret != 0) + return ret; if (get_user(pid, &header->pid)) return -EFAULT; @@ -281,7 +316,7 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data) permitted.cap[i] = kdata[i].permitted; inheritable.cap[i] = kdata[i].inheritable; } - while (i < _LINUX_CAPABILITY_U32S) { + while (i < _KERNEL_CAPABILITY_U32S) { effective.cap[i] = 0; permitted.cap[i] = 0; inheritable.cap[i] = 0; -- cgit v1.2.3 From 37340746a66e5e7feed5945f28cb75d90a8fd9f6 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Thu, 5 Jun 2008 22:46:32 -0700 Subject: cpusets: fix bug when adding nonexistent cpu or mem Adding a nonexistent cpu to a cpuset will be omitted quietly. It should return -EINVAL. Example: (real_nr_cpus <= 4 < NR_CPUS or cpu#4 was just offline) # cat cpus 0-1 # /bin/echo 4 > cpus # /bin/echo $? 0 # cat cpus # The same occurs when add a nonexistent mem. This patch will fix this bug. And when *buf == "", the check is unneeded. Signed-off-by: Lai Jiangshan Acked-by: Paul Jackson Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpuset.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 86ea9e34e326..039baa4cd90c 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -797,8 +797,10 @@ static int update_cpumask(struct cpuset *cs, char *buf) retval = cpulist_parse(buf, trialcs.cpus_allowed); if (retval < 0) return retval; + + if (!cpus_subset(trialcs.cpus_allowed, cpu_online_map)) + return -EINVAL; } - cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map); retval = validate_change(cs, &trialcs); if (retval < 0) return retval; @@ -932,9 +934,11 @@ static int update_nodemask(struct cpuset *cs, char *buf) retval = nodelist_parse(buf, trialcs.mems_allowed); if (retval < 0) goto done; + + if (!nodes_subset(trialcs.mems_allowed, + node_states[N_HIGH_MEMORY])) + return -EINVAL; } - nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, - node_states[N_HIGH_MEMORY]); oldmem = cs->mems_allowed; if (nodes_equal(oldmem, trialcs.mems_allowed)) { retval = 0; /* Too easy - nothing to do */ -- cgit v1.2.3 From 16882c1e962b4be5122fc05aaf2afc10fd9e2d15 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 8 Jun 2008 21:20:41 +0400 Subject: sched: fix TASK_WAKEKILL vs SIGKILL race schedule() has the special "TASK_INTERRUPTIBLE && signal_pending()" case, this allows us to do current->state = TASK_INTERRUPTIBLE; schedule(); without fear to sleep with pending signal. However, the code like current->state = TASK_KILLABLE; schedule(); is not right, schedule() doesn't take TASK_WAKEKILL into account. This means that mutex_lock_killable(), wait_for_completion_killable(), down_killable(), schedule_timeout_killable() can miss SIGKILL (and btw the second SIGKILL has no effect). Introduce the new helper, signal_pending_state(), and change schedule() to use it. Hopefully it will have more users, that is why the task's state is passed separately. Note this "__TASK_STOPPED | __TASK_TRACED" check in signal_pending_state(). This is needed to preserve the current behaviour (ptrace_notify). I hope this check will be removed soon, but this (afaics good) change needs the separate discussion. The fast path is "(state & (INTERRUPTIBLE | WAKEKILL)) + signal_pending(p)", basically the same that schedule() does now. However, this patch of course bloats schedule(). Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index bfb8ad8ed171..2c65bf29d133 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4159,12 +4159,10 @@ need_resched_nonpreemptible: clear_tsk_need_resched(prev); if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { - if (unlikely((prev->state & TASK_INTERRUPTIBLE) && - signal_pending(prev))) { + if (unlikely(signal_pending_state(prev->state, prev))) prev->state = TASK_RUNNING; - } else { + else deactivate_task(rq, prev, 1); - } switch_count = &prev->nvcsw; } -- cgit v1.2.3 From 2e084786f6fe052274f1dfa7c675fe4a02cacd6e Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Thu, 12 Jun 2008 16:42:58 +0800 Subject: sched: fair group: fix overflow(was: fix divide by zero) I found a bug which can be reproduced by this way:(linux-2.6.26-rc5, x86-64) (use 2^32, 2^33, ...., 2^63 as shares value) # mkdir /dev/cpuctl # mount -t cgroup -o cpu cpuctl /dev/cpuctl # cd /dev/cpuctl # mkdir sub # echo 0x8000000000000000 > sub/cpu.shares # echo $$ > sub/tasks oops here! divide by zero. This is because do_div() expects the 2th parameter to be 32 bits, but unsigned long is 64 bits in x86_64. Peter Zijstra pointed it out that the sane thing to do is limit the shares value to something smaller instead of using an even more expensive divide. Also, I found another bug about "the shares value is too large": pid1 and pid2 are set affinity to cpu#0 pid1 is attached to cg1 and pid2 is attached to cg2 if cg1/cpu.shares = 1024 cg2/cpu.shares = 2000000000 then pid2 got 100% usage of cpu, and pid1 0% if cg1/cpu.shares = 1024 cg2/cpu.shares = 20000000000 then pid2 got 0% usage of cpu, and pid1 100% And a weight of a cfs_rq is the sum of weights of which entities are queued on this cfs_rq, so the shares value should be limited to a smaller value. I think that (1UL << 18) is a good limited value: 1) it's not too large, we can create a lot of group before overflow 2) it's several times the weight value for nice=-19 (not too small) Signed-off-by: Lai Jiangshan Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 2c65bf29d133..6c1ecbdc0db9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -312,12 +312,15 @@ static DEFINE_SPINLOCK(task_group_lock); #endif /* - * A weight of 0, 1 or ULONG_MAX can cause arithmetics problems. + * A weight of 0 or 1 can cause arithmetics problems. + * A weight of a cfs_rq is the sum of weights of which entities + * are queued on this cfs_rq, so a weight of a entity should not be + * too large, so as the shares value of a task group. * (The default weight is 1024 - so there's no practical * limitation from this.) */ #define MIN_SHARES 2 -#define MAX_SHARES (ULONG_MAX - 1) +#define MAX_SHARES (1UL << 18) static int init_task_group_load = INIT_TASK_GROUP_LOAD; #endif -- cgit v1.2.3 From 7a232e0350940d2664f4de5cc3f0f443bae5062d Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Thu, 12 Jun 2008 16:43:07 +0800 Subject: sched: 64-bit: fix arithmetics overflow (overflow means weight >= 2^32 here, because inv_weigh = 2^32/weight) A weight of a cfs_rq is the sum of weights of which entities are queued on this cfs_rq, so it will overflow when there are too many entities. Although, overflow occurs very rarely, but it break fairness when it occurs. 64-bits systems have more memory than 32-bit systems and 64-bit systems can create more process usually, so overflow may occur more frequently. This patch guarantees fairness when overflow happens on 64-bit systems. Thanks to the optimization of compiler, it changes nothing on 32-bit. Signed-off-by: Lai Jiangshan Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 6c1ecbdc0db9..eaf6751e7612 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1340,8 +1340,13 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight, { u64 tmp; - if (!lw->inv_weight) - lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)/(lw->weight+1); + if (!lw->inv_weight) { + if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST)) + lw->inv_weight = 1; + else + lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2) + / (lw->weight+1); + } tmp = (u64)delta_exec * weight; /* -- cgit v1.2.3 From 67dddaad5d8b8c5ee5b96a7e2f6cb0faad703865 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 12 Jun 2008 15:21:35 -0700 Subject: kprobes: fix error checking of batch registration Fix error checking routine to catch an error which occurs in first __register_*probe(). Signed-off-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: David Miller Cc: Anil S Keshavamurthy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 1e0250cb9486..d4998f81e229 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -699,8 +699,9 @@ static int __register_kprobes(struct kprobe **kps, int num, return -EINVAL; for (i = 0; i < num; i++) { ret = __register_kprobe(kps[i], called_from); - if (ret < 0 && i > 0) { - unregister_kprobes(kps, i); + if (ret < 0) { + if (i > 0) + unregister_kprobes(kps, i); break; } } @@ -776,8 +777,9 @@ static int __register_jprobes(struct jprobe **jps, int num, jp->kp.break_handler = longjmp_break_handler; ret = __register_kprobe(&jp->kp, called_from); } - if (ret < 0 && i > 0) { - unregister_jprobes(jps, i); + if (ret < 0) { + if (i > 0) + unregister_jprobes(jps, i); break; } } @@ -920,8 +922,9 @@ static int __register_kretprobes(struct kretprobe **rps, int num, return -EINVAL; for (i = 0; i < num; i++) { ret = __register_kretprobe(rps[i], called_from); - if (ret < 0 && i > 0) { - unregister_kretprobes(rps, i); + if (ret < 0) { + if (i > 0) + unregister_kretprobes(rps, i); break; } } -- cgit v1.2.3 From 95e904c7da715aa2dbfb595da66b63de37a0bb04 Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Sun, 11 May 2008 05:55:33 +0530 Subject: sched: fix defined-but-unused warning Fix this warning, which appears with !CONFIG_SMP: kernel/sched.c:1216: warning: `init_hrtick' defined but not used Signed-off-by: Rabin Vincent Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index eaf6751e7612..04228524d160 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1127,6 +1127,7 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer) return HRTIMER_NORESTART; } +#ifdef CONFIG_SMP static void hotplug_hrtick_disable(int cpu) { struct rq *rq = cpu_rq(cpu); @@ -1182,6 +1183,7 @@ static void init_hrtick(void) { hotcpu_notifier(hotplug_hrtick, 0); } +#endif /* CONFIG_SMP */ static void init_rq_hrtick(struct rq *rq) { -- cgit v1.2.3 From 49307fd6f72bdd68cc2bd23e7da0bcfecf8087c9 Mon Sep 17 00:00:00 2001 From: Dario Faggioli Date: Wed, 18 Jun 2008 09:18:38 +0200 Subject: sched: NULL pointer dereference while setting sched_rt_period_us MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When CONFIG_RT_GROUP_SCHED and CONFIG_CGROUP_SCHED are enabled, with: echo 10000 > /proc/sys/kernel/sched_rt_period_us We get this: BUG: unable to handle kernel NULL pointer dereference at 0000008c [ 947.682233] IP: [] __rt_schedulable+0x12/0x160 [ 947.683123] *pde = 00000000=20 [ 947.683782] Oops: 0000 [#1] [ 947.684307] Modules linked in: [ 947.684308] [ 947.684308] Pid: 2359, comm: bash Not tainted (2.6.26-rc6 #8) [ 947.684308] EIP: 0060:[] EFLAGS: 00000246 CPU: 0 [ 947.684308] EIP is at __rt_schedulable+0x12/0x160 [ 947.684308] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000001 [ 947.684308] ESI: c0521db4 EDI: 00000001 EBP: c6cc9f00 ESP: c6cc9ed0 [ 947.684308] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 [ 947.684308] Process bash (pid: 2359, tiÆcc8000 taskÇa54f00=20 task.tiÆcc8000) [ 947.684308] Stack: c0222790 00000000 080f8c08 c0521db4 c6cc9f00 00000001 00000000 00000000 [ 947.684308] c6cc9f9c 00000000 c0521db4 00000001 c6cc9f28 c0216d40 00000000 00000000 [ 947.684308] c6cc9f9c 000f4240 000e7ef0 ffffffff c0521db4 c79dfb60 c6cc9f58 c02af2cc [ 947.684308] Call Trace: [ 947.684308] [] ? do_proc_dointvec_conv+0x0/0x50 [ 947.684308] [] ? sched_rt_handler+0x80/0x110 [ 947.684308] [] ? proc_sys_call_handler+0x9c/0xb0 [ 947.684308] [] ? proc_sys_write+0x1a/0x20 [ 947.684308] [] ? vfs_write+0x96/0x160 [ 947.684308] [] ? proc_sys_write+0x0/0x20 [ 947.684308] [] ? sys_write+0x3d/0x70 [ 947.684308] [] ? sysenter_past_esp+0x6a/0x91 [ 947.684308] ======================= [ 947.684308] Code: 24 04 e8 62 b1 0e 00 89 c7 89 f8 8b 5d f4 8b 75 f8 8b 7d fc 89 ec 5d c3 90 55 89 e5 57 56 53 83 ec 24 89 45 ec 89 55 e4 89 4d e8 <8b> b8 8c 00 00 00 85 ff 0f 84 c9 00 00 00 8b 57 24 39 55 e8 8b [ 947.684308] EIP: [] __rt_schedulable+0x12/0x160 SS:ESP 0068:c6cc9ed0 We think the following patch solves the issue. Signed-off-by: Dario Faggioli Signed-off-by: Michael Trimarchi Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 04228524d160..320e9a43d4cc 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8350,7 +8350,7 @@ static unsigned long to_ratio(u64 period, u64 runtime) #ifdef CONFIG_CGROUP_SCHED static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) { - struct task_group *tgi, *parent = tg->parent; + struct task_group *tgi, *parent = tg ? tg->parent : NULL; unsigned long total = 0; if (!parent) { -- cgit v1.2.3 From 7ea56616ba6b3d67a4892728182e38ae162ea3e7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Jun 2008 09:06:56 +0200 Subject: sched: rt-group: fix hierarchy Don't re-set the entity's runqueue to the wrong rq after we've set it to the right one. Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 320e9a43d4cc..ce375cb551e9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7628,7 +7628,6 @@ static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq, else rt_se->rt_rq = parent->my_q; - rt_se->rt_rq = &rq->rt; rt_se->my_q = rt_rq; rt_se->parent = parent; INIT_LIST_HEAD(&rt_se->run_list); -- cgit v1.2.3 From ad2a3f13b7258a5daaaeb8cff9f835aac468b71d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Jun 2008 09:06:57 +0200 Subject: sched: rt-group: heirarchy aware throttle The bandwidth throttle code dequeues a group when it runs out of quota, and re-queues it once the period rolls over and the quota gets refreshed. Sadly it failed to take the hierarchy into consideration. Share more of the enqueue/dequeue code with regular task opterations. Also, some operations like sched_setscheduler() can dequeue/enqueue tasks that are in throttled runqueues, we should not inadvertly re-enqueue empty runqueues so check for that. Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 59 +++++++++++++++++++++++++++++++------------------------ 1 file changed, 33 insertions(+), 26 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 3432d573205d..837241568d76 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -449,13 +449,19 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) #endif } -static void enqueue_rt_entity(struct sched_rt_entity *rt_se) +static void __enqueue_rt_entity(struct sched_rt_entity *rt_se) { struct rt_rq *rt_rq = rt_rq_of_se(rt_se); struct rt_prio_array *array = &rt_rq->active; struct rt_rq *group_rq = group_rt_rq(rt_se); - if (group_rq && rt_rq_throttled(group_rq)) + /* + * Don't enqueue the group if its throttled, or when empty. + * The latter is a consequence of the former when a child group + * get throttled and the current group doesn't have any other + * active members. + */ + if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) return; list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); @@ -464,7 +470,7 @@ static void enqueue_rt_entity(struct sched_rt_entity *rt_se) inc_rt_tasks(rt_se, rt_rq); } -static void dequeue_rt_entity(struct sched_rt_entity *rt_se) +static void __dequeue_rt_entity(struct sched_rt_entity *rt_se) { struct rt_rq *rt_rq = rt_rq_of_se(rt_se); struct rt_prio_array *array = &rt_rq->active; @@ -480,11 +486,10 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se) * Because the prio of an upper entry depends on the lower * entries, we must remove entries top - down. */ -static void dequeue_rt_stack(struct task_struct *p) +static void dequeue_rt_stack(struct sched_rt_entity *rt_se) { - struct sched_rt_entity *rt_se, *back = NULL; + struct sched_rt_entity *back = NULL; - rt_se = &p->rt; for_each_sched_rt_entity(rt_se) { rt_se->back = back; back = rt_se; @@ -492,7 +497,26 @@ static void dequeue_rt_stack(struct task_struct *p) for (rt_se = back; rt_se; rt_se = rt_se->back) { if (on_rt_rq(rt_se)) - dequeue_rt_entity(rt_se); + __dequeue_rt_entity(rt_se); + } +} + +static void enqueue_rt_entity(struct sched_rt_entity *rt_se) +{ + dequeue_rt_stack(rt_se); + for_each_sched_rt_entity(rt_se) + __enqueue_rt_entity(rt_se); +} + +static void dequeue_rt_entity(struct sched_rt_entity *rt_se) +{ + dequeue_rt_stack(rt_se); + + for_each_sched_rt_entity(rt_se) { + struct rt_rq *rt_rq = group_rt_rq(rt_se); + + if (rt_rq && rt_rq->rt_nr_running) + __enqueue_rt_entity(rt_se); } } @@ -506,32 +530,15 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) if (wakeup) rt_se->timeout = 0; - dequeue_rt_stack(p); - - /* - * enqueue everybody, bottom - up. - */ - for_each_sched_rt_entity(rt_se) - enqueue_rt_entity(rt_se); + enqueue_rt_entity(rt_se); } static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) { struct sched_rt_entity *rt_se = &p->rt; - struct rt_rq *rt_rq; update_curr_rt(rq); - - dequeue_rt_stack(p); - - /* - * re-enqueue all non-empty rt_rq entities. - */ - for_each_sched_rt_entity(rt_se) { - rt_rq = group_rt_rq(rt_se); - if (rt_rq && rt_rq->rt_nr_running) - enqueue_rt_entity(rt_se); - } + dequeue_rt_entity(rt_se); } /* -- cgit v1.2.3 From 15a8641eadb492ef7c5489faa25256967bdfd303 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Jun 2008 09:06:59 +0200 Subject: sched: rt-group: fix RR buglet In tick_task_rt() we first call update_curr_rt() which can dequeue a runqueue due to it running out of runtime, and then we try to requeue it, of it also having exhausted its RR quota. Obviously requeueing something that is no longer on the runqueue will not have the expected result. Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 837241568d76..1dad5bbb59b6 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -549,8 +549,10 @@ static void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) { struct rt_prio_array *array = &rt_rq->active; + struct list_head *queue = array->queue + rt_se_prio(rt_se); - list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); + if (on_rt_rq(rt_se)) + list_move_tail(&rt_se->run_list, queue); } static void requeue_task_rt(struct rq *rq, struct task_struct *p) -- cgit v1.2.3 From f18f982abf183e91f435990d337164c7a43d1e6d Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Thu, 29 May 2008 11:17:01 -0700 Subject: sched: CPU hotplug events must not destroy scheduler domains created by the cpusets First issue is not related to the cpusets. We're simply leaking doms_cur. It's allocated in arch_init_sched_domains() which is called for every hotplug event. So we just keep reallocation doms_cur without freeing it. I introduced free_sched_domains() function that cleans things up. Second issue is that sched domains created by the cpusets are completely destroyed by the CPU hotplug events. For all CPU hotplug events scheduler attaches all CPUs to the NULL domain and then puts them all into the single domain thereby destroying domains created by the cpusets (partition_sched_domains). The solution is simple, when cpusets are enabled scheduler should not create default domain and instead let cpusets do that. Which is exactly what the patch does. Signed-off-by: Max Krasnyansky Cc: pj@sgi.com Cc: menage@google.com Cc: rostedt@goodmis.org Acked-by: Peter Zijlstra Signed-off-by: Thomas Gleixner --- kernel/cpuset.c | 6 ++++++ kernel/sched.c | 22 ++++++++++++++++++++++ 2 files changed, 28 insertions(+) (limited to 'kernel') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 039baa4cd90c..bceb89557973 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1890,6 +1890,12 @@ static void common_cpu_mem_hotplug_unplug(void) top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; scan_for_empty_cpusets(&top_cpuset); + /* + * Scheduler destroys domains on hotplug events. + * Rebuild them based on the current settings. + */ + rebuild_sched_domains(); + cgroup_unlock(); } diff --git a/kernel/sched.c b/kernel/sched.c index ce375cb551e9..4a3cb0614158 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7237,6 +7237,18 @@ void __attribute__((weak)) arch_update_cpu_topology(void) { } +/* + * Free current domain masks. + * Called after all cpus are attached to NULL domain. + */ +static void free_sched_domains(void) +{ + ndoms_cur = 0; + if (doms_cur != &fallback_doms) + kfree(doms_cur); + doms_cur = &fallback_doms; +} + /* * Set up scheduler domains and groups. Callers must hold the hotplug lock. * For now this just excludes isolated cpus, but could be used to @@ -7384,6 +7396,7 @@ int arch_reinit_sched_domains(void) get_online_cpus(); mutex_lock(&sched_domains_mutex); detach_destroy_domains(&cpu_online_map); + free_sched_domains(); err = arch_init_sched_domains(&cpu_online_map); mutex_unlock(&sched_domains_mutex); put_online_cpus(); @@ -7469,6 +7482,7 @@ static int update_sched_domains(struct notifier_block *nfb, case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: detach_destroy_domains(&cpu_online_map); + free_sched_domains(); return NOTIFY_OK; case CPU_UP_CANCELED: @@ -7487,8 +7501,16 @@ static int update_sched_domains(struct notifier_block *nfb, return NOTIFY_DONE; } +#ifndef CONFIG_CPUSETS + /* + * Create default domain partitioning if cpusets are disabled. + * Otherwise we let cpusets rebuild the domains based on the + * current setup. + */ + /* The hotplug lock is already held by cpu_up/cpu_down */ arch_init_sched_domains(&cpu_online_map); +#endif return NOTIFY_OK; } -- cgit v1.2.3 From 30e0e178193d4221abc9926b07a4c7661c7cc4a9 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 13 May 2008 10:27:17 +0800 Subject: cpuset: limit the input of cpuset.sched_relax_domain_level We allow the inputs to be [-1 ... SD_LV_MAX), and return -EINVAL for inputs outside this range. Signed-off-by: Li Zefan Acked-by: Paul Menage Acked-by: Paul Jackson Acked-by: Hidetoshi Seto Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/cpuset.c | 4 ++-- kernel/sched.c | 7 ++++++- 2 files changed, 8 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 039baa4cd90c..66103a119bfe 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1037,8 +1037,8 @@ int current_cpuset_is_being_rebound(void) static int update_relax_domain_level(struct cpuset *cs, s64 val) { - if ((int)val < 0) - val = -1; + if (val < -1 || val >= SD_LV_MAX) + return -EINVAL; if (val != cs->relax_domain_level) { cs->relax_domain_level = val; diff --git a/kernel/sched.c b/kernel/sched.c index eaf6751e7612..bb2c699c9f5e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6877,7 +6877,12 @@ static int default_relax_domain_level = -1; static int __init setup_relax_domain_level(char *str) { - default_relax_domain_level = simple_strtoul(str, NULL, 0); + unsigned long val; + + val = simple_strtoul(str, NULL, 0); + if (val < SD_LV_MAX) + default_relax_domain_level = val; + return 1; } __setup("relax_domain_level=", setup_relax_domain_level); -- cgit v1.2.3 From afd38009cc3acd36d41f349a669ad5825d695b1f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 22 May 2008 14:18:17 -0400 Subject: rcupreempt: remove export of rcu_batches_completed_bh In rcupreempt, rcu_batches_completed_bh is defined as a static inline in the header file. This does not need to be exported, and not only that, this breaks my PPC build. Signed-off-by: Steven Rostedt Cc: "Paul E. McKenney" Cc: paulus@samba.org Cc: linuxppc-dev@ozlabs.org Signed-off-by: Thomas Gleixner --- kernel/rcupreempt.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c index e1cdf196a515..5e02b7740702 100644 --- a/kernel/rcupreempt.c +++ b/kernel/rcupreempt.c @@ -217,8 +217,6 @@ long rcu_batches_completed(void) } EXPORT_SYMBOL_GPL(rcu_batches_completed); -EXPORT_SYMBOL_GPL(rcu_batches_completed_bh); - void __rcu_read_lock(void) { int idx; -- cgit v1.2.3 From 9c106c119ebedf624fbd682fd2a4d52e3c8c1a67 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Tue, 27 May 2008 12:23:29 -0500 Subject: softlockup: fix NMI hangs due to lock race - 2.6.26-rc regression The touch_nmi_watchdog() routine on x86 ultimately calls touch_softlockup_watchdog(). The problem is that to touch the softlockup watchdog, the cpu_clock code has to be called which could involve multiple cpu locks and can lead to a hard hang if one of the locks is held by a processor that is not going to return anytime soon (such as could be the case with kgdb or perhaps even with some other kind of exception). This patch causes the public version of the touch_softlockup_watchdog() to defer the cpu clock access to a later point. The test case for this problem is to use the following kernel config options: CONFIG_KGDB_TESTS=y CONFIG_KGDB_TESTS_ON_BOOT=y CONFIG_KGDB_TESTS_BOOT_STRING="V1F100I100000" It should be noted that kgdb test suite and these options were not available until 2.6.26-rc2, so it was necessary to patch the kgdb test suite during the bisection. I would consider this patch a regression fix because the problem first appeared in commit 27ec4407790d075c325e1f4da0a19c56953cce23 when some logic was added to try to periodically sync the clocks. It was possible to work around this particular problem by simply not performing the sync anytime the system was in a critical context. This was ok until commit 3e51f33fcc7f55e6df25d15b55ed10c8b4da84cd, which added config option CONFIG_HAVE_UNSTABLE_SCHED_CLOCK and some multi-cpu locks to sync the clocks. It became clear that accessing this code from an nmi was the source of the lockups. Avoiding the access to the low level clock code from an code inside the NMI processing also fixed the problem with the 27ec44... commit. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- kernel/softlockup.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/softlockup.c b/kernel/softlockup.c index 01b6522fd92b..c828c2339cc9 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -49,12 +49,17 @@ static unsigned long get_timestamp(int this_cpu) return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */ } -void touch_softlockup_watchdog(void) +static void __touch_softlockup_watchdog(void) { int this_cpu = raw_smp_processor_id(); __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu); } + +void touch_softlockup_watchdog(void) +{ + __raw_get_cpu_var(touch_timestamp) = 0; +} EXPORT_SYMBOL(touch_softlockup_watchdog); void touch_all_softlockup_watchdogs(void) @@ -80,7 +85,7 @@ void softlockup_tick(void) unsigned long now; if (touch_timestamp == 0) { - touch_softlockup_watchdog(); + __touch_softlockup_watchdog(); return; } @@ -95,7 +100,7 @@ void softlockup_tick(void) /* do not print during early bootup: */ if (unlikely(system_state != SYSTEM_RUNNING)) { - touch_softlockup_watchdog(); + __touch_softlockup_watchdog(); return; } @@ -214,7 +219,7 @@ static int watchdog(void *__bind_cpu) sched_setscheduler(current, SCHED_FIFO, ¶m); /* initialize timestamp */ - touch_softlockup_watchdog(); + __touch_softlockup_watchdog(); set_current_state(TASK_INTERRUPTIBLE); /* @@ -223,7 +228,7 @@ static int watchdog(void *__bind_cpu) * debug-printout triggers in softlockup_tick(). */ while (!kthread_should_stop()) { - touch_softlockup_watchdog(); + __touch_softlockup_watchdog(); schedule(); if (kthread_should_stop()) -- cgit v1.2.3 From d4abc238c9f4df8b3216f3e883f5d0a07b7ac75a Mon Sep 17 00:00:00 2001 From: Bharath Ravi Date: Mon, 16 Jun 2008 15:11:01 +0530 Subject: sched, delay accounting: fix incorrect delay time when constantly waiting on runqueue This patch corrects the incorrect value of per process run-queue wait time reported by delay statistics. The anomaly was due to the following reason. When a process leaves the CPU and immediately starts waiting for CPU on the runqueue (which means it remains in the TASK_RUNNABLE state), the time of re-entry into the run-queue is never recorded. Due to this, the waiting time on the runqueue from this point of re-entry upto the next time it hits the CPU is not accounted for. This is solved by recording the time of re-entry of a process leaving the CPU in the sched_info_depart() function IF the process will go back to waiting on the run-queue. This IF condition is verified by checking whether the process is still in the TASK_RUNNABLE state. The patch was tested on 2.6.26-rc6 using two simple CPU hog programs. The values noted prior to the fix did not account for the time spent on the runqueue waiting. After the fix, the correct values were reported back to user space. Signed-off-by: Bharath Ravi Signed-off-by: Madhava K R Cc: dhaval@linux.vnet.ibm.com Cc: vatsa@in.ibm.com Cc: balbir@in.ibm.com Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched_stats.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/sched_stats.h b/kernel/sched_stats.h index a38878e0e49d..80179ef7450e 100644 --- a/kernel/sched_stats.h +++ b/kernel/sched_stats.h @@ -198,6 +198,9 @@ static inline void sched_info_queued(struct task_struct *t) /* * Called when a process ceases being the active-running process, either * voluntarily or involuntarily. Now we can calculate how long we ran. + * Also, if the process is still in the TASK_RUNNING state, call + * sched_info_queued() to mark that it has now again started waiting on + * the runqueue. */ static inline void sched_info_depart(struct task_struct *t) { @@ -206,6 +209,9 @@ static inline void sched_info_depart(struct task_struct *t) t->sched_info.cpu_time += delta; rq_sched_info_depart(task_rq(t), delta); + + if (t->state == TASK_RUNNING) + sched_info_queued(t); } /* -- cgit v1.2.3 From 8a8cde163ea724baf74e7752a31a69d3121a240e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Jun 2008 14:22:28 +0200 Subject: sched: rt: dont stop the period timer when there are tasks wanting to run So if the group ever gets throttled, it will never wake up again. Reported-by: "Daniel K." Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 1dad5bbb59b6..0f3c19197fa4 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -250,7 +250,8 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) if (rt_rq->rt_time || rt_rq->rt_nr_running) idle = 0; spin_unlock(&rt_rq->rt_runtime_lock); - } + } else if (rt_rq->rt_nr_running) + idle = 0; if (enqueue) sched_rt_rq_enqueue(rt_rq); -- cgit v1.2.3 From bb10ed0994927d433f6dbdf274fdb26cfcf516b7 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Thu, 19 Jun 2008 15:04:07 -0700 Subject: sched: fix wait_for_completion_timeout() spurious failure under heavy load It seems that the current implementaton of wait_for_completion_timeout() has a small problem under very high load for the common pattern: if (!wait_for_completion_timeout(&done, timeout)) /* handle failure */ because the implementation very roughly does (lots of code deleted to show the basic flow): static inline long __sched do_wait_for_common(struct completion *x, long timeout, int state) { if (x->done) return timeout; do { timeout = schedule_timeout(timeout); if (!timeout) return timeout; } while (!x->done); return timeout; } so if the system is very busy and x->done is not set when do_wait_for_common() is entered, it is possible that the first call to schedule_timeout() returns 0 because the task doing wait_for_completion doesn't get rescheduled for a long time, even if it is woken up early enough. In this case, wait_for_completion_timeout() returns 0 without even checking x->done again, and the code above falls into its failure case purely for scheduler reasons, even if the hardware event or whatever was being waited for happened early enough. It would make sense to add an extra test to do_wait_for() in the timeout case and return 1 if x->done is actually set. A quick audit (not exhaustive) of wait_for_completion_timeout() callers seems to indicate that no one actually cares about the return value in the success case -- they just test for 0 (timed out) versus non-zero (wait succeeded). Signed-off-by: Ingo Molnar --- kernel/sched.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 4a3cb0614158..577f160131bd 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4405,6 +4405,16 @@ do_wait_for_common(struct completion *x, long timeout, int state) spin_unlock_irq(&x->wait.lock); timeout = schedule_timeout(timeout); spin_lock_irq(&x->wait.lock); + + /* + * If the completion has arrived meanwhile + * then return 1 jiffy time left: + */ + if (x->done && !timeout) { + timeout = 1; + break; + } + if (!timeout) { __remove_wait_queue(&x->wait, &wait); return timeout; -- cgit v1.2.3 From ea71a546706dfdad72462624394e1e472c6bf34f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 20 Jun 2008 18:32:20 +0400 Subject: sched: refactor wait_for_completion_timeout() Simplify the code and fix the boundary condition of wait_for_completion_timeout(,0). We can kill the first __remove_wait_queue() as well. Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra --- kernel/sched.c | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 577f160131bd..bebf9788f45e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4398,32 +4398,20 @@ do_wait_for_common(struct completion *x, long timeout, int state) signal_pending(current)) || (state == TASK_KILLABLE && fatal_signal_pending(current))) { - __remove_wait_queue(&x->wait, &wait); - return -ERESTARTSYS; + timeout = -ERESTARTSYS; + break; } __set_current_state(state); spin_unlock_irq(&x->wait.lock); timeout = schedule_timeout(timeout); spin_lock_irq(&x->wait.lock); - - /* - * If the completion has arrived meanwhile - * then return 1 jiffy time left: - */ - if (x->done && !timeout) { - timeout = 1; - break; - } - - if (!timeout) { - __remove_wait_queue(&x->wait, &wait); - return timeout; - } - } while (!x->done); + } while (!x->done && timeout); __remove_wait_queue(&x->wait, &wait); + if (!x->done) + return timeout; } x->done--; - return timeout; + return timeout ?: 1; } static long __sched -- cgit v1.2.3 From 1b7558e457ed0de61023cfc913d2c342c7c3d9f2 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 23 Jun 2008 11:21:58 +0200 Subject: futexes: fix fault handling in futex_lock_pi This patch addresses a very sporadic pi-futex related failure in highly threaded java apps on large SMP systems. David Holmes reported that the pi_state consistency check in lookup_pi_state triggered with his test application. This means that the kernel internal pi_state and the user space futex variable are out of sync. First we assumed that this is a user space data corruption, but deeper investigation revieled that the problem happend because the pi-futex code is not handling a fault in the futex_lock_pi path when the user space variable needs to be fixed up. The fault happens when a fork mapped the anon memory which contains the futex readonly for COW or the page got swapped out exactly between the unlock of the futex and the return of either the new futex owner or the task which was the expected owner but failed to acquire the kernel internal rtmutex. The current futex_lock_pi() code drops out with an inconsistent in case it faults and returns -EFAULT to user space. User space has no way to fixup that state. When we wrote this code we thought that we could not drop the hash bucket lock at this point to handle the fault. After analysing the code again it turned out to be wrong because there are only two tasks involved which might modify the pi_state and the user space variable: - the task which acquired the rtmutex - the pending owner of the pi_state which did not get the rtmutex Both tasks drop into the fixup_pi_state() function before returning to user space. The first task which acquired the hash bucket lock faults in the fixup of the user space variable, drops the spinlock and calls futex_handle_fault() to fault in the page. Now the second task could acquire the hash bucket lock and tries to fixup the user space variable as well. It either faults as well or it succeeds because the first task already faulted the page in. One caveat is to avoid a double fixup. After returning from the fault handling we reacquire the hash bucket lock and check whether the pi_state owner has been modified already. Reported-by: David Holmes Signed-off-by: Thomas Gleixner Cc: Andrew Morton Cc: David Holmes Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Signed-off-by: Ingo Molnar kernel/futex.c | 93 ++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 73 insertions(+), 20 deletions(-) --- kernel/futex.c | 93 +++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 73 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 449def8074fe..7d1136e97c14 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1096,21 +1096,64 @@ static void unqueue_me_pi(struct futex_q *q) * private futexes. */ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, - struct task_struct *newowner) + struct task_struct *newowner, + struct rw_semaphore *fshared) { u32 newtid = task_pid_vnr(newowner) | FUTEX_WAITERS; struct futex_pi_state *pi_state = q->pi_state; + struct task_struct *oldowner = pi_state->owner; u32 uval, curval, newval; - int ret; + int ret, attempt = 0; /* Owner died? */ + if (!pi_state->owner) + newtid |= FUTEX_OWNER_DIED; + + /* + * We are here either because we stole the rtmutex from the + * pending owner or we are the pending owner which failed to + * get the rtmutex. We have to replace the pending owner TID + * in the user space variable. This must be atomic as we have + * to preserve the owner died bit here. + * + * Note: We write the user space value _before_ changing the + * pi_state because we can fault here. Imagine swapped out + * pages or a fork, which was running right before we acquired + * mmap_sem, that marked all the anonymous memory readonly for + * cow. + * + * Modifying pi_state _before_ the user space value would + * leave the pi_state in an inconsistent state when we fault + * here, because we need to drop the hash bucket lock to + * handle the fault. This might be observed in the PID check + * in lookup_pi_state. + */ +retry: + if (get_futex_value_locked(&uval, uaddr)) + goto handle_fault; + + while (1) { + newval = (uval & FUTEX_OWNER_DIED) | newtid; + + curval = cmpxchg_futex_value_locked(uaddr, uval, newval); + + if (curval == -EFAULT) + goto handle_fault; + if (curval == uval) + break; + uval = curval; + } + + /* + * We fixed up user space. Now we need to fix the pi_state + * itself. + */ if (pi_state->owner != NULL) { spin_lock_irq(&pi_state->owner->pi_lock); WARN_ON(list_empty(&pi_state->list)); list_del_init(&pi_state->list); spin_unlock_irq(&pi_state->owner->pi_lock); - } else - newtid |= FUTEX_OWNER_DIED; + } pi_state->owner = newowner; @@ -1118,26 +1161,35 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, WARN_ON(!list_empty(&pi_state->list)); list_add(&pi_state->list, &newowner->pi_state_list); spin_unlock_irq(&newowner->pi_lock); + return 0; /* - * We own it, so we have to replace the pending owner - * TID. This must be atomic as we have preserve the - * owner died bit here. + * To handle the page fault we need to drop the hash bucket + * lock here. That gives the other task (either the pending + * owner itself or the task which stole the rtmutex) the + * chance to try the fixup of the pi_state. So once we are + * back from handling the fault we need to check the pi_state + * after reacquiring the hash bucket lock and before trying to + * do another fixup. When the fixup has been done already we + * simply return. */ - ret = get_futex_value_locked(&uval, uaddr); +handle_fault: + spin_unlock(q->lock_ptr); - while (!ret) { - newval = (uval & FUTEX_OWNER_DIED) | newtid; + ret = futex_handle_fault((unsigned long)uaddr, fshared, attempt++); - curval = cmpxchg_futex_value_locked(uaddr, uval, newval); + spin_lock(q->lock_ptr); - if (curval == -EFAULT) - ret = -EFAULT; - if (curval == uval) - break; - uval = curval; - } - return ret; + /* + * Check if someone else fixed it for us: + */ + if (pi_state->owner != oldowner) + return 0; + + if (ret) + return ret; + + goto retry; } /* @@ -1507,7 +1559,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, * that case: */ if (q.pi_state->owner != curr) - ret = fixup_pi_state_owner(uaddr, &q, curr); + ret = fixup_pi_state_owner(uaddr, &q, curr, fshared); } else { /* * Catch the rare case, where the lock was released @@ -1539,7 +1591,8 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, int res; owner = rt_mutex_owner(&q.pi_state->pi_mutex); - res = fixup_pi_state_owner(uaddr, &q, owner); + res = fixup_pi_state_owner(uaddr, &q, owner, + fshared); /* propagate -EFAULT, if the fixup failed */ if (res) -- cgit v1.2.3 From aabdc3b8c3b3d081f1532454e344208338478e29 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Tue, 24 Jun 2008 10:52:55 -0500 Subject: kgdb: sparse fix - Fix warning reported by sparse kernel/kgdb.c:1502:6: warning: symbol 'kgdb_console_write' was not declared. Should it be static? Signed-off-by: Jason Wessel --- kernel/kgdb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 79e3c90113c2..3ec23c3ec97f 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -1499,7 +1499,8 @@ int kgdb_nmicallback(int cpu, void *regs) return 1; } -void kgdb_console_write(struct console *co, const char *s, unsigned count) +static void kgdb_console_write(struct console *co, const char *s, + unsigned count) { unsigned long flags; -- cgit v1.2.3 From 13d5ef97f0675d789f559cfebc1df9d5e2b1879c Mon Sep 17 00:00:00 2001 From: Peng Haitao Date: Fri, 16 May 2008 10:15:04 +0800 Subject: [PATCH] kernel/audit.c: nlh->nlmsg_type is gotten more than once The first argument "nlh->nlmsg_type" of audit_receive_filter() should be modified to "msg_type" in audit_receive_msg(). Signed-off-by: Peng Haitao Signed-off-by: Al Viro --- kernel/audit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/audit.c b/kernel/audit.c index e8692a5748c2..56f30287e24c 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -779,7 +779,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) } /* fallthrough */ case AUDIT_LIST: - err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, + err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid, uid, seq, data, nlmsg_len(nlh), loginuid, sessionid, sid); break; @@ -798,7 +798,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) } /* fallthrough */ case AUDIT_LIST_RULES: - err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, + err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid, uid, seq, data, nlmsg_len(nlh), loginuid, sessionid, sid); break; -- cgit v1.2.3 From 9f0aecdd1cd6aacee9aa8f08031f4f2e09e454dc Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Mon, 19 May 2008 15:09:21 -0700 Subject: [PATCH] audit: fix kernel-doc parameter notation Fix auditfilter kernel-doc misssing parameter description: Warning(lin2626-rc3//kernel/auditfilter.c:1551): No description found for parameter 'sessionid' Signed-off-by: Randy Dunlap Signed-off-by: Al Viro --- kernel/auditfilter.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index 0e0bd27e6512..75cdf262851d 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -1544,6 +1544,7 @@ static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid, * @data: payload data * @datasz: size of payload data * @loginuid: loginuid of sender + * @sessionid: sessionid for netlink audit message * @sid: SE Linux Security ID of sender */ int audit_receive_filter(int type, int pid, int uid, int seq, void *data, -- cgit v1.2.3 From d8de72473effd674a3c1fe9621821f406f5587c9 Mon Sep 17 00:00:00 2001 From: Peng Haitao Date: Tue, 20 May 2008 09:13:02 +0800 Subject: [PATCH] remove useless argument type in audit_filter_user() The second argument "type" is not used in audit_filter_user(), so I think that type can be removed. If I'm wrong, please tell me. Signed-off-by: Peng Haitao Signed-off-by: Al Viro --- kernel/audit.c | 2 +- kernel/auditfilter.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/audit.c b/kernel/audit.c index 56f30287e24c..e092f1c0ce30 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -738,7 +738,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (!audit_enabled && msg_type != AUDIT_USER_AVC) return 0; - err = audit_filter_user(&NETLINK_CB(skb), msg_type); + err = audit_filter_user(&NETLINK_CB(skb)); if (err == 1) { err = 0; if (msg_type == AUDIT_USER_TTY) { diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index 75cdf262851d..98c50cc671bb 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -1721,7 +1721,7 @@ static int audit_filter_user_rules(struct netlink_skb_parms *cb, return 1; } -int audit_filter_user(struct netlink_skb_parms *cb, int type) +int audit_filter_user(struct netlink_skb_parms *cb) { enum audit_state state = AUDIT_DISABLED; struct audit_entry *e; -- cgit v1.2.3 From 79c537998d143b127c8c662a403c3356cb885f1c Mon Sep 17 00:00:00 2001 From: Dmitry Adamushko Date: Sun, 29 Jun 2008 00:16:56 +0200 Subject: sched: fix cpu hotplug the CPU hotplug problems (crashes under high-volume unplug+replug tests) seem to be related to migrate_dead_tasks(). Firstly I added traces to see all tasks being migrated with migrate_live_tasks() and migrate_dead_tasks(). On my setup the problem pops up (the one with "se == NULL" in the loop of pick_next_task_fair()) shortly after the traces indicate that some has been migrated with migrate_dead_tasks()). btw., I can reproduce it much faster now with just a plain cpu down/up loop. [disclaimer] Well, unless I'm really missing something important in this late hour [/desclaimer] pick_next_task() is not something appropriate for migrate_dead_tasks() :-) the following change seems to eliminate the problem on my setup (although, I kept it running only for a few minutes to get a few messages indicating migrate_dead_tasks() does move tasks and the system is still ok) Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 3aaa5c8cb421..a66e85639de2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5887,6 +5887,7 @@ static void migrate_dead_tasks(unsigned int dead_cpu) next = pick_next_task(rq, rq->curr); if (!next) break; + next->sched_class->put_prev_task(rq, next); migrate_dead(dead_cpu, next); } -- cgit v1.2.3 From 619b0488038224391e64fa03854651ca0f5efe56 Mon Sep 17 00:00:00 2001 From: Raistlin Date: Thu, 26 Jun 2008 18:54:09 +0200 Subject: sched: fix divide error when trying to configure rt_period to zero Here it is another little Oops we found while configuring invalid values via cgroups: echo 0 > /dev/cgroups/0/cpu.rt_period_us or echo 4294967296 > /dev/cgroups/0/cpu.rt_period_us [ 205.509825] divide error: 0000 [#1] [ 205.510151] Modules linked in: [ 205.510151] [ 205.510151] Pid: 2339, comm: bash Not tainted (2.6.26-rc8 #33) [ 205.510151] EIP: 0060:[] EFLAGS: 00000293 CPU: 0 [ 205.510151] EIP is at div64_u64+0x5f/0x70 [ 205.510151] EAX: 0000389f EBX: 00000000 ECX: 00000000 EDX: 00000000 [ 205.510151] ESI: d9800000 EDI: 00000000 EBP: c6cede60 ESP: c6cede50 [ 205.510151] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 [ 205.510151] Process bash (pid: 2339, ti=c6cec000 task=c79be370 task.ti=c6cec000) [ 205.510151] Stack: d9800000 0000389f c05971a0 d9800000 c6cedeb4 c0214dbd 00000000 00000000 [ 205.510151] c6cede88 c0242bd8 c05377c0 c7a41b40 00000000 00000000 00000000 c05971a0 [ 205.510151] c780ed20 c7508494 c7a41b40 00000000 00000002 c6cedebc c05971a0 ffffffea [ 205.510151] Call Trace: [ 205.510151] [] ? __rt_schedulable+0x1cd/0x240 [ 205.510151] [] ? cgroup_file_open+0x18/0xe0 [ 205.510151] [] ? tg_set_bandwidth+0xa4/0xf0 [ 205.510151] [] ? sched_group_set_rt_period+0x36/0x50 [ 205.510151] [] ? cpu_rt_period_write_uint+0xe/0x10 [ 205.510151] [] ? cgroup_file_write+0x125/0x160 [ 205.510151] [] ? hrtimer_interrupt+0x155/0x190 [ 205.510151] [] ? security_file_permission+0xf/0x20 [ 205.510151] [] ? rw_verify_area+0x48/0xc0 [ 205.510151] [] ? dupfd+0x104/0x130 [ 205.510151] [] ? vfs_write+0x9c/0x160 [ 205.510151] [] ? cgroup_file_write+0x0/0x160 [ 205.510151] [] ? sys_write+0x3d/0x70 [ 205.510151] [] ? sysenter_past_esp+0x6a/0x91 [ 205.510151] ======================= [ 205.510151] Code: 0f 45 de 31 f6 0f ad d0 d3 ea f6 c1 20 0f 45 c2 0f 45 d6 89 45 f0 89 55 f4 8b 55 f4 31 c9 8b 45 f0 39 d3 89 c6 77 08 89 d0 31 d2 f3 89 c1 83 c4 08 89 f0 f7 f3 89 ca 5b 5e 5d c3 55 89 e5 56 [ 205.510151] EIP: [] div64_u64+0x5f/0x70 SS:ESP 0068:c6cede50 The attached patch solves the issue for me. I'm checking as soon as possible for the period not being zero since, if it is, going ahead is useless. This way we also save a mutex_lock() and a read_lock() wrt doing it inside tg_set_bandwidth() or __rt_schedulable(). Signed-off-by: Dario Faggioli Signed-off-by: Michael Trimarchi Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index a66e85639de2..94ead43eda62 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8502,6 +8502,9 @@ int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) rt_period = (u64)rt_period_us * NSEC_PER_USEC; rt_runtime = tg->rt_bandwidth.rt_runtime; + if (rt_period == 0) + return -EINVAL; + return tg_set_bandwidth(tg, rt_period, rt_runtime); } -- cgit v1.2.3 From 8558f8f81680a43d383abd1b5f23d3501fedfa65 Mon Sep 17 00:00:00 2001 From: Gautham R Shenoy Date: Fri, 27 Jun 2008 10:17:38 +0530 Subject: rcu: fix hotplug vs rcu race Dhaval Giani reported this warning during cpu hotplug stress-tests: | On running kernel compiles in parallel with cpu hotplug: | | WARNING: at arch/x86/kernel/smp.c:118 | native_smp_send_reschedule+0x21/0x36() | Modules linked in: | Pid: 27483, comm: cc1 Not tainted 2.6.26-rc7 #1 | [...] | [] native_smp_send_reschedule+0x21/0x36 | [] force_quiescent_state+0x47/0x57 | [] call_rcu+0x51/0x6d | [] __fput+0x130/0x158 | [] fput+0x17/0x19 | [] filp_close+0x4d/0x57 | [] sys_close+0x5c/0x97 IMHO the warning is a spurious one. cpu_online_map is updated by the _cpu_down() using stop_machine_run(). Since force_quiescent_state is invoked from irqs disabled section, stop_machine_run() won't be executing while a cpu is executing force_quiescent_state(). Hence the cpu_online_map is stable while we're in the irq disabled section. However, a cpu might have been offlined _just_ before we disabled irqs while entering force_quiescent_state(). And rcu subsystem might not yet have handled the CPU_DEAD notification, leading to the offlined cpu's bit being set in the rcp->cpumask. Hence cpumask = (rcp->cpumask & cpu_online_map) to prevent sending smp_reschedule() to an offlined CPU. Here's the timeline: CPU_A CPU_B -------------------------------------------------------------- cpu_down(): . . . . . stop_machine(): /* disables preemption, . * and irqs */ . . . . . take_cpu_down(); . . . . . . . cpu_disable(); /*this removes cpu . *from cpu_online_map . */ . . . . . restart_machine(); /* enables irqs */ . ------WINDOW DURING WHICH rcp->cpumask is stale --------------- . call_rcu(); . /* disables irqs here */ . .force_quiescent_state(); .CPU_DEAD: .for_each_cpu(rcp->cpumask) . . smp_send_reschedule(); . . . . WARN_ON() for offlined CPU! . . . rcu_cpu_notify: . -------- WINDOW ENDS ------------------------------------------ rcu_offline_cpu() /* Which calls cpu_quiet() * which removes * cpu from rcp->cpumask. */ If a new batch was started just before calling stop_machine_run(), the "tobe-offlined" cpu is still present in rcp-cpumask. During a cpu-offline, from take_cpu_down(), we queue an rt-prio idle task as the next task to be picked by the scheduler. We also call cpu_disable() which will disable any further interrupts and remove the cpu's bit from the cpu_online_map. Once the stop_machine_run() successfully calls take_cpu_down(), it calls schedule(). That's the last time a schedule is called on the offlined cpu, and hence the last time when rdp->passed_quiesc will be set to 1 through rcu_qsctr_inc(). But the cpu_quiet() will be on this cpu will be called only when the next RCU_SOFTIRQ occurs on this CPU. So at this time, the offlined CPU is still set in rcp->cpumask. Now coming back to the idle_task which truely offlines the CPU, it does check for a pending RCU and raises the softirq, since it will find rdp->passed_quiesc to be 0 in this case. However, since the cpu is offline I am not sure if the softirq will trigger on the CPU. Even if it doesn't the rcu_offline_cpu() will find that rcp->completed is not the same as rcp->cur, which means that our cpu could be holding up the grace period progression. Hence we call cpu_quiet() and move ahead. But because of the window explained in the timeline, we could still have a call_rcu() before the RCU subsystem executes it's CPU_DEAD notification, and we send smp_send_reschedule() to offlined cpu while trying to force the quiescent states. The appended patch adds comments and prevents checking for offlined cpu everytime. cpu_online_map is updated by the _cpu_down() using stop_machine_run(). Since force_quiescent_state is invoked from irqs disabled section, stop_machine_run() won't be executing while a cpu is executing force_quiescent_state(). Hence the cpu_online_map is stable while we're in the irq disabled section. Reported-by: Dhaval Giani Signed-off-by: Gautham R Shenoy Acked-by: Dhaval Giani Cc: Dipankar Sarma Cc: laijs@cn.fujitsu.com Cc: Peter Zijlstra Cc: Rusty Russel Cc: "Paul E. McKenney" Signed-off-by: Ingo Molnar --- kernel/rcuclassic.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c index f4ffbd0f306f..a38895a5b8e2 100644 --- a/kernel/rcuclassic.c +++ b/kernel/rcuclassic.c @@ -89,8 +89,22 @@ static void force_quiescent_state(struct rcu_data *rdp, /* * Don't send IPI to itself. With irqs disabled, * rdp->cpu is the current cpu. + * + * cpu_online_map is updated by the _cpu_down() + * using stop_machine_run(). Since we're in irqs disabled + * section, stop_machine_run() is not exectuting, hence + * the cpu_online_map is stable. + * + * However, a cpu might have been offlined _just_ before + * we disabled irqs while entering here. + * And rcu subsystem might not yet have handled the CPU_DEAD + * notification, leading to the offlined cpu's bit + * being set in the rcp->cpumask. + * + * Hence cpumask = (rcp->cpumask & cpu_online_map) to prevent + * sending smp_reschedule() to an offlined CPU. */ - cpumask = rcp->cpumask; + cpus_and(cpumask, rcp->cpumask, cpu_online_map); cpu_clear(rdp->cpu, cpumask); for_each_cpu_mask(cpu, cpumask) smp_send_reschedule(cpu); -- cgit v1.2.3 From ee3ece830f6db9837f7ac67008f532a8c1e755f4 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Jul 2008 14:31:26 -0400 Subject: hrtimer: prevent migration for raising softirq Due to a possible deadlock, the waking of the softirq was pushed outside of the hrtimer base locks. See commit 0c96c5979a522c3323c30a078a70120e29b5bdbc Unfortunately this allows the task to migrate after setting up the softirq and raising it. Since softirqs run a queue that is per-cpu we may raise the softirq on the wrong CPU and this will keep the queued softirq task from running. To solve this issue, this patch disables preemption around the releasing of the hrtimer lock and raising of the softirq. Signed-off-by: Steven Rostedt Signed-off-by: Linus Torvalds --- kernel/hrtimer.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 421be5fe5cc7..ab80515008f4 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1003,10 +1003,18 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) */ raise = timer->state == HRTIMER_STATE_PENDING; + /* + * We use preempt_disable to prevent this task from migrating after + * setting up the softirq and raising it. Otherwise, if me migrate + * we will raise the softirq on the wrong CPU. + */ + preempt_disable(); + unlock_hrtimer_base(timer, &flags); if (raise) hrtimer_raise_softirq(); + preempt_enable(); return ret; } -- cgit v1.2.3 From cde53535991fbb5c34a1566f25955297c1487b8d Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Fri, 4 Jul 2008 09:59:22 -0700 Subject: Christoph has moved Remove all clameter@sgi.com addresses from the kernel tree since they will become invalid on June 27th. Change my maintainer email address for the slab allocators to cl@linux-foundation.org (which will be the new email address for the future). Signed-off-by: Christoph Lameter Signed-off-by: Christoph Lameter Cc: Pekka Enberg Cc: Stephen Rothwell Cc: Matt Mackall Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 29fc39f1029c..ce7799540c91 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -13,7 +13,7 @@ * Kai Petzke * Theodore Ts'o * - * Made to use alloc_percpu by Christoph Lameter . + * Made to use alloc_percpu by Christoph Lameter. */ #include -- cgit v1.2.3 From 086f7316f0d400806d76323beefae996bb3849b1 Mon Sep 17 00:00:00 2001 From: "Andrew G. Morgan" Date: Fri, 4 Jul 2008 09:59:58 -0700 Subject: security: filesystem capabilities: fix fragile setuid fixup code This commit includes a bugfix for the fragile setuid fixup code in the case that filesystem capabilities are supported (in access()). The effect of this fix is gated on filesystem capability support because changing securebits is only supported when filesystem capabilities support is configured.) [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew G. Morgan Acked-by: Serge Hallyn Acked-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/capability.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'kernel') diff --git a/kernel/capability.c b/kernel/capability.c index cfbe44299488..901e0fdc3fff 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -121,6 +121,27 @@ static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy) * uninteresting and/or not to be changed. */ +/* + * Atomically modify the effective capabilities returning the original + * value. No permission check is performed here - it is assumed that the + * caller is permitted to set the desired effective capabilities. + */ +kernel_cap_t cap_set_effective(const kernel_cap_t pE_new) +{ + kernel_cap_t pE_old; + + spin_lock(&task_capability_lock); + + pE_old = current->cap_effective; + current->cap_effective = pE_new; + + spin_unlock(&task_capability_lock); + + return pE_old; +} + +EXPORT_SYMBOL(cap_set_effective); + /** * sys_capget - get the capabilities of a given process. * @header: pointer to struct that contains capability version and -- cgit v1.2.3 From 3b7253238801a7b97b3929d8db2fa7a0721fb17b Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Mon, 16 Jun 2008 15:51:08 -0700 Subject: softlockup: print a module list on being stuck Most places in the kernel that go BUG: print a module list (which is very useful for doing statistics and finding patterns), however the softlockup detector does not do this yet. This patch adds the one line change to fix this gap. Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar --- kernel/softlockup.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/softlockup.c b/kernel/softlockup.c index c828c2339cc9..a272d78185eb 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -120,6 +120,7 @@ void softlockup_tick(void) printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n", this_cpu, now - touch_timestamp, current->comm, task_pid_nr(current)); + print_modules(); if (regs) show_regs(regs); else -- cgit v1.2.3