[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>

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 8a0afb97af71..5cd833bc2173 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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