Re: Oops 2.6.23.1 in ext3+jbd at journal_put_journal_head

From: Mark Lord
Date: Tue Nov 13 2007 - 13:30:33 EST


Jan Kara wrote:
Hello,

A one-time event thus far, happened under very heavy I/O,
Dell i9400 Core2Duo notebook w/3GB ram, single SATA drive with ext3.
Had to cycle power to get it back and see this Oops in the syslog:
..
Hmm, your pointer to buffer_head in journal_head has been overwritten
by some garbage - it actually looks like ASCII ("C\n ra"). I think your
journal_head pointer is stored in EAX (at least if I compile SMP kernel
for i386 it is) and that is 0xc2bd7000 - start of the page. So probably
..

As for me, I'm guessing a use/free race somewhere, but with
only the information from the Oops that's hard to know.

some driver went wild and overwritten a piece of memory which did not
belong to it... I suggest turning on a few debugging options (like
DEBUG_SLAB) to catch the offender.
..

You mean, like, this:

#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.23.1-slab
# Wed Nov 7 08:00:18 2007
#
CONFIG_X86_32=y
...
CONFIG_DEBUG_SLAB=y
...

Thought since it was..

A one-time event thus far ...
..

.. I'm unlikely to see it again.

Cheers
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