Messages in this thread | | | Date | Wed, 22 Apr 2015 16:28:38 -0400 | From | Waiman Long <> | Subject | Re: [PATCH] xfs: call xfs_idestroy_fork() in xfs_ilock() critical section |
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On 04/22/2015 03:11 PM, Brian Foster wrote: > On Wed, Apr 22, 2015 at 01:33:41PM -0400, Waiman Long wrote: >> The commit f7be2d7f594cbc ("xfs: push down inactive transaction >> mgmt for truncate") refactored the xfs_inactive() function >> in fs/xfs/xfs_inode.c. However, it also moved the call to >> xfs_idestroy_fork() from inside the xfs_ilock() critical section to >> outside. That was causing memory corruption and strange failures like >> deferencing NULL pointers in some circumstances. >> >> This patch moves the xfs_idestroy_fork() call back into an xfs_ilock() >> critical section to avoid memory corruption problem. >> >> Signed-off-by: Waiman Long<Waiman.Long@hp.com> >> --- > Interesting... so from your previous mail we have an inactive/reclaim > racing with an xfs_iflush_fork() of the attr fork, or something of that > nature? Is there a specific reproducer or is it some kind of stress > test? > > Good catch in any case, it looks like a deviation from the previous > code...
I am not sure what kind of races are going on. I was running the AIM7 workload for performance comparison purpose. I hit the error when running the disk workload with xfs filesystem. The smaller the ramdisk that I used, the easier it was to reproduce the error. I think I haven't run it for quite a while so I did not notice any problem or I might have just ignored it in some previous runs.
I did check some other call sites of xfs_idestroy_fork() and they are under xfs_ilock(). So I suppose it is not safe to call it outside of the critical section. This patch did indeed fix the problem that I saw when running the disk workload.
Cheers, Longman
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