Re: kernel BUG at fs/buffer.c:3205 (stable 3.5.3)

From: Alexander Holler
Date: Thu Sep 27 2012 - 11:47:07 EST


Hello,

Am 27.09.2012 17:12, schrieb Jan Kara:
Just some thoughts about your oops:
The assertion which fails is:
BUG_ON(!list_empty(&bh->b_assoc_buffers));

Now b_assoc_buffers isn't used very much. In particular ext4 which you seem
to be using doesn't use this list at all (except when mounted in nojournal
mode but that doesn't seem to be your case). That would point rather
strongly at a memory corruption issue.

So if you can reproduce the oops, it might be interesting to print
bh->b_assoc_buffers.next and &bh->b_assoc_buffers.next if the list is found
to be non-empty.

Hmm, a loose pointer would explain it all too. Especially the cases when I just have seen wrong content in the archive without having any oops. I try to reproduce it with

pr_info("AHO: %p %p\n", bh->b_assoc_buffers.next, &bh->b_assoc_buffers.next);

after the BUG_ON().

Thanks for the hint. I wasn't already that far to know that b_assoc_buffers isn't used that much.

Regards,

Alexander
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