Messages in this thread | | | Date | Wed, 6 Dec 2006 09:47:48 +0100 (CET) | From | Jiri Kosina <> | Subject | Re: [PATCH] let WARN_ON() output the condition |
| |
On Wed, 6 Dec 2006, Ingo Molnar wrote:
> a WARN_ON() also triggers a stack dump, which should pinpoint the exact > location. (especially if combined with kallsyms) For example:
Actually, I was referring to something a little bit different. For example kernel/mutex.c:__mutex_lock_common() calls spin_lock_mutex() on line 132. spin_lock_mutex() contains
DEBUG_LOCKS_WARN_ON(in_interrupt()); \ local_irq_save(flags); \ __raw_spin_lock(&(lock)->raw_lock); \ DEBUG_LOCKS_WARN_ON(l->magic != l); \
When one of these two WARN_ONs trigger, we get only
WARNING at kernel/mutex.c:132 __mutex_lock_common()
but it's indistuingishable which of the two WARN_ONs triggered. My patch turns this into
WARNING (l->magic != l) at kernel/mutex.c:132 __mutex_lock_common()
> side-effects happen regularly in WARN_ON()s and while they should be > avoided, they are not noticed by the compiler and can cause nasty bugs > if executed twice. Do we really need this change?
I absolutely don't insist on it to be merged, besides this Andrew also pointed out non-trivial .text growth. I just cooked it up for myself when debugging some locking problems and that warning at kernel/mutex.c:132 triggered, and I didn't know which one was the reason.
-- Jiri Kosina - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |