Re: 2.2.0(release): oops in kmem_cache_free (??)

Andi Kleen (ak@muc.de)
26 Jan 1999 22:32:35 +0100

In article <19990126185555.A14971@Galois.suse.de>,
werner@suse.de (Dr. Werner Fink) writes:
> On Tue, Jan 26, 1999 at 12:26:25PM -0500, David J. Fred wrote:
>>
>> Summary: This morning I found my machine had crashed during the night
>> on the release version of 2.2.0, apparently in kmem_cache_free.

> Yep, I've seen a similar oops during a high stress test on a UP system
> (two make -j10 in different kernel trees). The only problem was that
> the oops in the kernel message wasn't fully readable for ksysmoops
> (bit garbage). After running fsck by hand to recover /dev/sda10 aka
> /usr/src/ the system is up again.

The oops is caused by this code in kmem_cache_free:

#if 1
/* FORCE A KERNEL DUMP WHEN THIS HAPPENS. SPEAK IN ALL CAPS. GET THE CALL CHAIN. */
*(int *) 0 = 0;
#endif

There should be kmem_alloc: ... message directly in front of the oops
in the kernel log. what does it say?

As far as I can see the problem can only happen when a process in the
process list carries a bogus pointer in tsk->mm. The new locking in
array.c has the side effect of noticing it in mmput.

-Andi

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