Messages in this thread | | | Subject | Re: 2.6.18 ext3 panic. | From | Badari Pulavarty <> | Date | Mon, 09 Oct 2006 14:59:25 -0700 |
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On Mon, 2006-10-09 at 14:46 -0500, Eric Sandeen wrote: > Andrew Morton wrote: > > On Tue, 03 Oct 2006 00:43:01 -0500 > > Eric Sandeen <sandeen@sandeen.net> wrote: > > > >> Dave Jones wrote: > >> > >>> So I managed to reproduce it with an 'fsx foo' and a > >>> 'fsstress -d . -r -n 100000 -p 20 -r'. This time I grabbed it from > >>> a vanilla 2.6.18 with none of the Fedora patches.. > >>> > >>> I'll give 2.6.18-git a try next. > >>> > >>> Dave > >>> > >>> ----------- [cut here ] --------- [please bite here ] --------- > >>> Kernel BUG at fs/buffer.c:2791 > >> I had thought/hoped that this was fixed by Jan's patch at > >> http://lkml.org/lkml/2006/9/7/236 from the thread started at > >> http://lkml.org/lkml/2006/9/1/149, but it seems maybe not. Dave hit this bug > >> first by going through that new codepath.... > > > > Yes, Jan's patch is supposed to fix that !buffer_mapped() assertion. iirc, > > Badari was hitting that BUG and was able to confirm that Jan's patch > > (3998b9301d3d55be8373add22b6bc5e11c1d9b71 in post-2.6.18 mainline) fixed > > it. > > Looking at some BH traces*, it appears that what Dave hit is a truncate > racing with a sync... > > truncate ... > ext3_invalidate_page > journal_invalidatepage > journal_unmap buffer > > going off at the same time as > > sync ... > journal_dirty_data > sync_dirty_buffer > submit_bh <-- finds unmapped buffer, boom. >
I don't understand how this can happen ..
journal_unmap_buffer() zapping the buffer since its not attached to any transaction.
journal_unmap_buffer():[fs/jbd/transaction.c:1789] not on any transaction: zap b_state:0x10402f b_jlist:BJ_None cpu:0 b_count:3 b_blocknr:52735707 b_jbd:1 b_frozen_data:0000000000000000 b_committed_data:0000000000000000 b_transaction:0 b_next_transaction:0 b_cp_transaction:0 b_trans_is_running:0 b_trans_is_comitting:0 b_jcount:2 pg_dirty:1
journal_dirty_data() would do submit_bh() ONLY if its part of the older transaction.
I need to take a closer look to understand the race.
BTW, is this 1k or 2k filesystem ? How easy is to reproduce the problem ?
Thanks, Badari
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