Re: WARNING: at kernel/lockdep.c:690 __lock_acquire+0x168/0x164b()

From: Borislav Petkov
Date: Thu Oct 20 2011 - 14:39:21 EST


On Sat, Oct 15, 2011 at 03:32:32PM -0700, David Rientjes wrote:
> Could you try to revert f59de8992aa6 ("lockdep: Clear whole lockdep_map on
> initialization") with this patch and see if it helps? Thanks.
> ---
> diff --git a/kernel/lockdep.c b/kernel/lockdep.c
> --- a/kernel/lockdep.c
> +++ b/kernel/lockdep.c
> @@ -2874,7 +2874,10 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
> void lockdep_init_map(struct lockdep_map *lock, const char *name,
> struct lock_class_key *key, int subclass)
> {
> - memset(lock, 0, sizeof(*lock));
> + int i;
> +
> + for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
> + lock->class_cache[i] = NULL;
>
> #ifdef CONFIG_LOCK_STAT
> lock->cpu = raw_smp_processor_id();

FWIW,

the box has been running here with f59de8992aa6 reverted for a couple of
days now and no sign of the warning. I'll keep watching it but it looks
ok so far, so David, you could've nailed it.

Thanks.

--
Regards/Gruss,
Boris.
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