diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2012-10-05 08:56:15 +0100 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2012-10-16 12:57:41 -0400 |
| commit | 973fb8fb6fcbb0037a48a53e21ce2dfe72627c76 (patch) | |
| tree | 095f8117742beb34ca11f768c6fa58dea2ef254a | |
| parent | 9211e429aafebefd4ed2a7804686e75fe1d03cb1 (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 ea235b62a63b..38f910416a0a 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); @@ -8483,6 +8495,13 @@ 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 } |