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| author | Steven Rostedt <srostedt@redhat.com> | 2011-04-20 21:41:56 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-04-22 11:06:58 +0200 |
| commit | 48702ecf308e53f176c1f6fdc193d622ded54ac0 (patch) | |
| tree | aa348b35b3a97fd9a5230e145ea4e6186ab2a978 /kernel/lockdep.c | |
| parent | f4185812aa046ecb97e8817e10148cacdd7a6baa (diff) | |
| download | linux-48702ecf308e53f176c1f6fdc193d622ded54ac0.tar.bz2 | |
lockdep: Print a nicer description for simple deadlocks
Lockdep output can be pretty cryptic, having nicer output
can save a lot of head scratching. When a simple deadlock
scenario is detected by lockdep (lock A -> lock A) we now
get the following new output:
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(lock)->rlock);
lock(&(lock)->rlock);
*** 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/20110421014259.643930104@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/lockdep.c')
| -rw-r--r-- | kernel/lockdep.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 73cebd7aa719..c4cc5d1acf48 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1664,6 +1664,26 @@ static inline void inc_chains(void) #endif +static void +print_deadlock_scenario(struct held_lock *nxt, + struct held_lock *prv) +{ + struct lock_class *next = hlock_class(nxt); + struct lock_class *prev = hlock_class(prv); + + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0\n"); + printk(" ----\n"); + printk(" lock("); + __print_lock_name(prev); + printk(");\n"); + printk(" lock("); + __print_lock_name(next); + printk(");\n"); + printk("\n *** DEADLOCK ***\n\n"); + printk(" May be due to missing lock nesting notation\n\n"); +} + static int print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, struct held_lock *next) @@ -1682,6 +1702,7 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, print_lock(prev); printk("\nother info that might help us debug this:\n"); + print_deadlock_scenario(next, prev); lockdep_print_held_locks(curr); printk("\nstack backtrace:\n"); |