Messages in this thread | | | Date | Sun, 8 Aug 2004 10:36:19 +0100 | From | Russell King <> | Subject | Re: [BUG] 2.6.8-rc3 slab corruption (jffs2?) |
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On Sun, Aug 08, 2004 at 11:23:06AM +0200, Manfred Spraul wrote: > rmk wrote: > >Due to tail call optimisation, its difficult to work out exactly what's > >going on, but the first seems to be a kfree call from the erase callback > >(possibly jffs2_erase_callback). The second function is the call to > >jffs2_free_full_dirent() in jffs2_garbage_collect_deletion_dirent(). > > I'd concentrate on cfi_intelext_erase_varsize+0x58/0x64: > When slab encounters a corruption, it dumps three objects: the corrupted > one, the previous one and the next one. Theoretically, a write > before/after the end of the object could corrupt the neighboring object, > but probably the first function is the relevant one.
Remember - we report the _return_ address of a function when we use __builtin_return_address(0) in that function.
This means that if kfree() is called from a tail-call optimised position, the reported address will be the parent function of the one which actually called it.
Therefore, cfi_intelext_erase_varsize() called some other function (in this case, via a function pointer) which then called kfree() in a tail-call optimised position. jffs2_erase_callback() would be called from this function pointer and does have kfree() in a tail-call optimised position.
However, reading the code around jffs2_erase_callback() and jffs2_erase_block(), I can find nothing obviously wrong.
The main problem is that I don't actually know what triggered it in the first place - I'd just booted the machine and was just logging in when it poped up, but repeating this does not cause the problem.
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/ 2.6 Serial core - 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/
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