Messages in this thread | | | Date | Thu, 12 Jun 2008 13:35:20 +0300 (EEST) | From | Pekka J Enberg <> | Subject | Re: repeatable slab corruption with LTP msgctl08 |
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Hi Andrew,
On Wed, 11 Jun 2008, Andrew Morton wrote: > version is ltp-full-20070228 (lots of retro-computing there). > > Config is at http://userweb.kernel.org/~akpm/config-vmm.txt > > ./testcases/bin/msgctl08 crashes after ten minutes or so: > > slab: Internal list corruption detected in cache 'size-128'(26), slabp f2905000(20). Hexdump: > > 000: 00 e0 12 f2 88 32 c0 f7 88 00 00 00 88 50 90 f2 > 010: 14 00 00 00 0f 00 00 00 00 00 00 00 ff ff ff ff > 020: fd ff ff ff fd ff ff ff fd ff ff ff fd ff ff ff > 030: fd ff ff ff fd ff ff ff fd ff ff ff fd ff ff ff > 040: fd ff ff ff fd ff ff ff 00 00 00 00 fd ff ff ff > 050: fd ff ff ff fd ff ff ff 19 00 00 00 17 00 00 00 > 060: fd ff ff ff fd ff ff ff 0b 00 00 00 fd ff ff ff > 070: fd ff ff ff fd ff ff ff fd ff ff ff fd ff ff ff > 080: 10 00 00 00
Looking at the above dump, slabp->free is 0x0f and the bufctl it points to is 0xff ("BUFCTL_END") which marks the last element in the chain. This is wrong as the total number of objects in the slab (cachep->num) is 26 but the number of objects in use (slabp->inuse) is 20. So somehow you have managed to lost 6 objects from the bufctl chain.
I really don't understand how your bufctl chains has so many BUFCTL_END elements in the first place. It's doesn't look like the memory has been stomped on (slab->s_mem, for example, is 0xf2906088), so I'd look for a double kfree() of size 128 somewhere...
Pekka
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