xfs_vm_releasepage() causing BUG at free_buffer_head()

[Dave Chinner]

On Mon, Jul 18, 2016 at 09:00:41PM +0300, Alex Lyakas wrote:
> Greetings XFS community,
> 
> We have hit the following BUG [1].
> 
> This is in free_buffer_head():
> BUG_ON(!list_empty(&bh->b_assoc_buffers));

XFS doesn't use the bh->b_assoc_buffers field at all, so nothing in
XFS should ever corrupt it. Do you have any extN filesystems active,
or any other filesystems/block devices that use bufferheads than
might have a use after free bug? e.g. a long time ago (circa
~2.6.16, IIRC) we had a bufferhead corruption problem detected in
XFS that was actually caused by a reiserfs use after free.

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com