Re: PROBLEM: Kernel 2.6.10 crashing repeatedly and hard

Linus Torvalds
2004-12-30T22:23:20Z

On Thu, 30 Dec 2004, Georg C. F. Greve wrote:
>
> lt> Any chance that you can get a full oops, with register info?
> lt> Right now your errors only have the call trace, not the registers
> lt> or the EIP itself..
>
> Yes, for the first two times, the top of the crash report scrolled off
> the screen and I don't have a serial console handy. The third crash
> contained the
>
> EFLAGS: 00010002 (2.6.10)
> EIP is at free_block+0x45/0xd0
> eax: 46484849 ebx: df2b1000 ecx: df2b1050 edx: df2ab000
> esi: c183cd80 edi: 00000001 ebp: 00000018 esp: c188fef8
> ds: 007b es: 007b ss: 0068
> Process events/0 (pid: 6, threadinfo:c188e000 task=c185ca20)
> Stack: c183cdb8 c1858810 c1858800 00000018 c183cd80 c0141724 c183cd80 c1858810
> 00000018 c183ccb8 c183cd80 00000002 c183cce0 c01417c6 c183cd80 c1858800
> 00000000 c183ccb8 c183ce10 00000003 c170fc20 c183b000 c170fc24 00000000
>
> header, which I think may contain what you were looking for.

Ok. This is apparently a slab cache corruption issue.

Can you compile with SLAB_DEBUG and DEBUG_PAGEALLOC turned on, since that
may well catch something in the act (or it may make the machine so
unusably slow that it's not funny - who knows..)

> Meanwhile, because of the trouble, I gave Alans patch-2.6.10-ac1 a try
> and again put ext3 on dm-crypt on raid5, and: No crash so far despite
> moving and removing ~100 gigabytes a couple of times on to/from the
> partition.

Goodie. Maybe Alan already knows what it's about. Alan? Any slab
corruption or wild pointers that you are aware of? However:

> I did however get occasional
>
> EXT3-fs error (device dm-0): ext3_readdir: bad entry in directory #37306376: directory entry across blocks - offset=0, inode=3350155169, rec_len=11148, name_len=1

I suspect that it's more of the slab corruption thing, and Alan's patch
ended up moving something around subtly enough that you don't get the
crash, but instead get corrupted buffer heads or similar.. Your BTTV
issues are interesting, though.

Linus