diff options
| author | Steven Rostedt <srostedt@redhat.com> | 2011-04-20 21:41:59 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-04-22 11:06:59 +0200 |
| commit | 282b5c2f6f663c008444321fd8fcdd374596046b (patch) | |
| tree | 33d189c35bccdccfaef281a90afd3451c5ae115f /kernel/lockdep.c | |
| parent | 6be8c3935b914dfbc24b27c91c2b6d583645e61a (diff) | |
lockdep: Print a nicer description for simple irq lock inversions
Lockdep output can be pretty cryptic, having nicer output
can save a lot of head scratching. When a simple irq inversion
scenario is detected by lockdep (lock A taken in interrupt
context but also in thread context without disabling interrupts)
we now get the following (hopefully more informative) output:
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(lockA);
<Interrupt>
lock(lockA);
*** DEADLOCK ***
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110421014300.436140880@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/lockdep.c')
| -rw-r--r-- | kernel/lockdep.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 270cfa405d3..27c609f3eae 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2158,6 +2158,24 @@ static void check_chain_key(struct task_struct *curr) #endif } +static void +print_usage_bug_scenario(struct held_lock *lock) +{ + struct lock_class *class = hlock_class(lock); + + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0\n"); + printk(" ----\n"); + printk(" lock("); + __print_lock_name(class); + printk(");\n"); + printk(" <Interrupt>\n"); + printk(" lock("); + __print_lock_name(class); + printk(");\n"); + printk("\n *** DEADLOCK ***\n\n"); +} + static int print_usage_bug(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) @@ -2186,6 +2204,8 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this, print_irqtrace_events(curr); printk("\nother info that might help us debug this:\n"); + print_usage_bug_scenario(this); + lockdep_print_held_locks(curr); printk("\nstack backtrace:\n"); |