xfs_vm_releasepage() causing BUG at free_buffer_head()

[Holger Hoffstätte]

On 07/18/16 20:00, 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));
> 
> This is happening in a long-term mainline kernel 3.18.19.
> 
> Some googling revealed a possibly-related discussion at:
> http://comments.gmane.org/gmane.linux.file-systems/105093
> https://lkml.org/lkml/2016/5/30/1007
> except that in our case I don't see the "WARN_ON_ONCE(delalloc)" triggered.

Since you make it past the WARN_ONs that makes it look like this
very recent report from Friday:

http://oss.sgi.com/pipermail/xfs/2016-July/050199.html

Dave posted a patch in that thread which seems ot work fine and so
far hasn't set anything on fire, at least for me on 4.4.x.

cheers,
Holger