diff options
| author | Vegard Nossum <vegard.nossum@oracle.com> | 2016-07-23 09:46:39 +0200 |
|---|---|---|
| committer | Mohammed Khajapasha <mkhaja@codeaurora.org> | 2017-03-30 13:30:38 +0530 |
| commit | 4748cf2bdee373fba9cec3f1f7e95928ae21c100 (patch) | |
| tree | 0c31f9caae0b9beff69956ace442c1114610fdc8 /kernel | |
| parent | 6f55033ecf068f77136caac2e7c4a7869b3ec2bd (diff) | |
sched/debug: Make the "Preemption disabled at ..." message more useful
This message is currently really useless since it always prints a value
that comes from the printk() we just did, e.g.:
BUG: sleeping function called from invalid context at mm/slab.h:388
in_atomic(): 0, irqs_disabled(): 0, pid: 31996, name: trinity-c1
Preemption disabled at:[<ffffffff8119db33>] down_trylock+0x13/0x80
BUG: sleeping function called from invalid context at include/linux/freezer.h:56
in_atomic(): 0, irqs_disabled(): 0, pid: 31996, name: trinity-c1
Preemption disabled at:[<ffffffff811aaa37>] console_unlock+0x2f7/0x930
Here, both down_trylock() and console_unlock() is somewhere in the
printk() path.
We should save the value before calling printk() and use the saved value
instead. That immediately reveals the offending callsite:
BUG: sleeping function called from invalid context at mm/slab.h:388
in_atomic(): 0, irqs_disabled(): 0, pid: 14971, name: trinity-c2
Preemption disabled at:[<ffffffff819bcd46>] rhashtable_walk_start+0x46/0x150
Bug report:
http://marc.info/?l=linux-netdev&m=146925979821849&w=2
Change-Id: I5b08294385a2ac625dbf28d1f18ffd164aedabe0
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russel <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[mkhaja@codeaurora.org: Fix trivial merge conflict]
Git-commit: d1c6d149cf04d6c7c3c3ebf4b66c82500cbcf6e1
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Mohammed Khajapasha <mkhaja@codeaurora.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 312ffdad034a..caf0475f5722 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3362,6 +3362,9 @@ NOKPROBE_SYMBOL(preempt_count_sub); */ static noinline void __schedule_bug(struct task_struct *prev) { + /* Save this before calling printk(), since that will clobber it */ + unsigned long preempt_disable_ip = get_preempt_disable_ip(current); + if (oops_in_progress) return; @@ -3372,13 +3375,12 @@ static noinline void __schedule_bug(struct task_struct *prev) print_modules(); if (irqs_disabled()) print_irqtrace_events(prev); -#ifdef CONFIG_DEBUG_PREEMPT - if (in_atomic_preempt_off()) { + if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) + && in_atomic_preempt_off()) { pr_err("Preemption disabled at:"); - print_ip_sym(current->preempt_disable_ip); + print_ip_sym(preempt_disable_ip); pr_cont("\n"); } -#endif #ifdef CONFIG_PANIC_ON_SCHED_BUG BUG(); #endif @@ -8511,6 +8513,7 @@ EXPORT_SYMBOL(__might_sleep); void ___might_sleep(const char *file, int line, int preempt_offset) { static unsigned long prev_jiffy; /* ratelimiting */ + unsigned long preempt_disable_ip; rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && @@ -8523,6 +8526,9 @@ void ___might_sleep(const char *file, int line, int preempt_offset) return; prev_jiffy = jiffies; + /* Save this before calling printk(), since that will clobber it */ + preempt_disable_ip = get_preempt_disable_ip(current); + printk(KERN_ERR "BUG: sleeping function called from invalid context at %s:%d\n", file, line); @@ -8537,13 +8543,12 @@ void ___might_sleep(const char *file, int line, int preempt_offset) debug_show_held_locks(current); if (irqs_disabled()) print_irqtrace_events(current); -#ifdef CONFIG_DEBUG_PREEMPT - if (!preempt_count_equals(preempt_offset)) { + if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) + && !preempt_count_equals(preempt_offset)) { pr_err("Preemption disabled at:"); - print_ip_sym(current->preempt_disable_ip); + print_ip_sym(preempt_disable_ip); pr_cont("\n"); } -#endif #ifdef CONFIG_PANIC_ON_SCHED_BUG BUG(); #endif |