On Mon, Sep 15, 2008 at 12:40:04PM +1000, Lachlan McIlroy wrote:
> Dave Chinner wrote:
>> On Fri, Sep 12, 2008 at 06:41:07PM +1000, Lachlan McIlroy wrote:
>>> Destroying the quota stuff on unmount can access the log - ie XFS_QM_DONE()
>>> ends up in xfs_dqunlock() which calls xfs_trans_unlocked_item() and then
>>> xfs_log_move_tail(). By this time the log has already been destroyed.
>>> Just move the cleanup of the quota code earlier in xfs_unmountfs() before
>>> the call to xfs_log_unmount(). Moving XFS_QM_DONE() up near
>>> XFS_QM_DQPURGEALL() seems like a good spot.
>> FWIW, has this been actually seen in the real world?
> Yes. And easy to reproduce too.
Care to provide details about the test case, then? I can't help if
you keep me in the dark....
>> torn down the AIL and there should be no log items in the system
>> that are in the AIL....
> That should be the case but clearly not happening. Pete is investigating
> an issue right now where a dquot is not getting removed from the AIL when
> it should. Until we've got to the bottom of that problem I'd prefer to at
> least avoid this use after free issue.
No point in putting a bandaid in if you're already in the process of
trying to find the real cause....