Re: Top 10 bugs/warnings for the week of March 23rd, 2008

[Jan Kara]

  Hello,

> Rank 3: mark_buffer_dirty
> 	Reported 253 times (547 total reports)
> 	EXT3 bug while hot-removing a USB device
> 	This oops was last seen in version 2.6.25.3, and first seen in 
> 	2.6.24-rc6.
> 	More info: 
> 	http://www.kerneloops.org/searchweek.php?search=mark_buffer_dirty
  Is someone looking into this? It could be somehow connected with commit
1be62dc190ebaca331038962c873e7967de6cc4b where we add smp_mb() to
mark_buffer_dirty() under some circumstances. But I don't really see
how. The WARN_ON() being triggered is !buffer_uptodate(bh) but that
seems ridiculous for call paths like ext2_sync_super() ->
mark_buffer_dirty() or journal_destroy() -> journal_update_superblock() ->
mark_buffer_dirty() which are in oopses. Also this warning started
appearing only recently while ext2 and JBD didn't change those areas
recently. Also interesting may be that both ext2_sync_super() and
journal_update_superblock() call sync_dirty_buffer() just after calling
mark_buffer_dirty()...
  Arjan, do we have some more info for these oopses (like hw config,
what was the machine doing while the WARN_ON has been triggered etc.)?
Thanks.

								Honza
-- 
Jan Kara <jack@xxxxxxx>
SuSE CR Labs
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