Re: [CRED bug?] 2.6.29-rc3 don't survive on stress workload

[Vegard Nossum <vegard.nossum@gmail.com>]

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On Tue, Feb 10, 2009 at 6:41 AM, KOSAKI Motohiro
<kosaki.motohiro@jp.fujitsu.com> wrote:
> Hi
>
> I periodically test kernel on stress workload.
> Unfortunately, recent kerenel don't survive >24H.
>
> It paniced with following stack.
> Do you have any suggestions?
>
> thanks!

That stack trace looks somewhat similar to the one in
http://lkml.org/lkml/2009/2/6/136

If this is reproducible, maybe a patch like the one attached can help
pinpoint it?


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036

[-- Attachment #2: kref-warn_on.patch --]
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diff --git a/lib/kref.c b/lib/kref.c
index 1599dbf..a547ad3 100644
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -40,7 +40,7 @@ void kref_init(struct kref *kref)
  */
 void kref_get(struct kref *kref)
 {
-	WARN_ON(!atomic_read(&kref->refcount));
+	WARN_ON(atomic_read(&kref->refcount) <= 0);
 	atomic_inc(&kref->refcount);
 	smp_mb__after_atomic_inc();
 }
@@ -63,7 +63,7 @@ int kref_put(struct kref *kref, void (*release)(struct kref *kref))
 {
 	WARN_ON(release == NULL);
 	WARN_ON(release == (void (*)(struct kref *))kfree);
-	WARN_ON(!atomic_read(&kref->refcount));
+	WARN_ON(atomic_read(&kref->refcount) <= 0);
 
 	if (atomic_dec_and_test(&kref->refcount)) {
 		release(kref);