[PATCH] lockdep: print irq-trace info on asserts

When we print an assert due to scheduling-in-atomic bugs, and if lockdep
is enabled, then the IRQ tracing information of lockdep can be printed
to pinpoint the code location that disabled interrupts. This saved me
quite a bit of debugging time in cases where the backtrace did not
identify the irq-disabling site well enough.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar 2006-12-13 00:34:43 -08:00 committed by Linus Torvalds
parent 27c3b23226
commit 3117df0453
3 changed files with 18 additions and 8 deletions

View File

@ -281,15 +281,25 @@ struct lock_class_key { };
#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)
extern void early_init_irq_lock_class(void);
#else
# define early_init_irq_lock_class() do { } while (0)
static inline void early_init_irq_lock_class(void)
{
}
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
extern void early_boot_irqs_off(void);
extern void early_boot_irqs_on(void);
extern void print_irqtrace_events(struct task_struct *curr);
#else
# define early_boot_irqs_off() do { } while (0)
# define early_boot_irqs_on() do { } while (0)
static inline void early_boot_irqs_off(void)
{
}
static inline void early_boot_irqs_on(void)
{
}
static inline void print_irqtrace_events(struct task_struct *curr)
{
}
#endif
/*

View File

@ -1447,7 +1447,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,
return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
}
static inline void print_irqtrace_events(struct task_struct *curr)
void print_irqtrace_events(struct task_struct *curr)
{
printk("irq event stamp: %u\n", curr->irq_events);
printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
@ -1460,10 +1460,6 @@ static inline void print_irqtrace_events(struct task_struct *curr)
print_ip_sym(curr->softirq_disable_ip);
}
#else
static inline void print_irqtrace_events(struct task_struct *curr)
{
}
#endif
static int

View File

@ -3429,6 +3429,8 @@ asmlinkage void __sched schedule(void)
"%s/0x%08x/%d\n",
current->comm, preempt_count(), current->pid);
debug_show_held_locks(current);
if (irqs_disabled())
print_irqtrace_events(current);
dump_stack();
}
profile_hit(SCHED_PROFILING, __builtin_return_address(0));
@ -6977,6 +6979,8 @@ void __might_sleep(char *file, int line)
printk("in_atomic():%d, irqs_disabled():%d\n",
in_atomic(), irqs_disabled());
debug_show_held_locks(current);
if (irqs_disabled())
print_irqtrace_events(current);
dump_stack();
}
#endif