diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2012-10-05 08:56:15 +0100 |
|---|---|---|
| committer | Steven Rostedt <rostedt@rostedt.homelinux.com> | 2012-10-26 14:42:58 -0400 |
| commit | f95a16e7bd4c6d6cff48166b642ed4eb56f71bde (patch) | |
| tree | 244fa99400cd80d1e775a9c1a763857524f1a326 | |
| parent | a8e008c6d2a35d8aed78f55489c4ec5a86d6251e (diff) | |
sched: Better debug output for might sleep
might sleep can tell us where interrupts have been disabled, but we
have no idea what disabled preemption. Add some debug infrastructure.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | include/linux/sched.h | 4 | ||||
| -rw-r--r-- | kernel/sched.c | 23 |
2 files changed, 25 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 8155129c9f01..a179dd0e5e0a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1606,6 +1606,10 @@ struct task_struct { int kmap_idx; pte_t kmap_pte[KM_TYPE_NR]; #endif + +#ifdef CONFIG_DEBUG_PREEMPT + unsigned long preempt_disable_ip; +#endif }; #ifdef CONFIG_PREEMPT_RT_FULL diff --git a/kernel/sched.c b/kernel/sched.c index e7aa85adcd9b..2cf4c4bdf0e0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4121,8 +4121,13 @@ void __kprobes add_preempt_count(int val) DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK - 10); #endif - if (preempt_count() == val) - trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); + if (preempt_count() == val) { + unsigned long ip = get_parent_ip(CALLER_ADDR1); +#ifdef CONFIG_DEBUG_PREEMPT + current->preempt_disable_ip = ip; +#endif + trace_preempt_off(CALLER_ADDR0, ip); + } } EXPORT_SYMBOL(add_preempt_count); @@ -4164,6 +4169,13 @@ static noinline void __schedule_bug(struct task_struct *prev) print_modules(); if (irqs_disabled()) print_irqtrace_events(prev); +#ifdef DEBUG_PREEMPT + if (in_atomic_preempt_off()) { + pr_err("Preemption disabled at:"); + print_ip_sym(current->preempt_disable_ip); + pr_cont("\n"); + } +#endif if (regs) show_regs(regs); @@ -8515,6 +8527,13 @@ void __might_sleep(const char *file, int line, int preempt_offset) debug_show_held_locks(current); if (irqs_disabled()) print_irqtrace_events(current); +#ifdef DEBUG_PREEMPT + if (!preempt_count_equals(preempt_offset)) { + pr_err("Preemption disabled at:"); + print_ip_sym(current->preempt_disable_ip); + pr_cont("\n"); + } +#endif dump_stack(); #endif } |