Re: xfs_io "BUG: lock held when returning to user space!" on suspend

From: David Chinner
Date: Wed Apr 02 2008 - 17:58:03 EST


On Wed, Apr 02, 2008 at 11:58:54AM -0700, Jeremy Fitzhardinge wrote:
> I'm getting this:
>
> ================================================
> [ BUG: lock held when returning to user space! ]
> ------------------------------------------------
> xfs_io/18796 is leaving the kernel with locks still held!
> 1 lock held by xfs_io/18796:
> #0: (&type->s_umount_key#19){----}, at: [<c048c9ac>] get_super+0x42/0x87
>
> when I suspend, possibly during an xfs-freeze. There don't seem to be any
> ill-effects.

Yup, both the sb->s_umount and bdev->bd_mount_sem seaphores are held
across freeze_bdev()/thaw_bdev(), and they are issued via separate
ioctls generally from separate processes. Not great design, but not
a bug....

Cheers,

Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group
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