[OpenAFS-devel] Linux: inode freed while on LRU (change in d_splice_alias?)

[Michael Laß]

I just saw bug #131967. This looks quite similar to me.

Michael

Am Freitag, den 05.12.2014, 08:36 -0400 schrieb Marc Dionne:
> On Fri, Dec 5, 2014 at 3:20 AM, Michael Laß <lass@mail.upb.de> wrote:
> > Hi,
> >
> > an ArchLinux user reported an issue with OpenAFS on recent Linux kernels
> > to me. When unmounting /afs after using it he gets the following error:
> >
> >> openafs: inode freed while on LRU
> >> ------------[ cut here ]------------
> >> kernel BUG at /var/lib/dkms/openafs/1.6.11pre1/build/src/libafs/MODLOAD-3.17.4-1-ARCH-SP/osi_vfsops.c:291!
> >
> > This happens using OpenAFS 1.6.10 (11549, 11550 applied on top) and
> > 1.6.11pre1.
> >
> > It seems that this issue was introduced after Linux 3.17.2, so I had a
> > look at the changes and found this one here introduced in 3.17.3:
> > https://lkml.org/lkml/2014/11/11/1597
> >
> > If I understand this correctly the kernel now frees the inode reference
> > that's still used in OpenAFS. Is that correct? If not, some further
> > debugging might be necessary and the user will jump into this thread.
> >
> > Greetings,
> > Michael
> 
> Thanks for the pointer, yes that kernel patch would cause a problem,
> as in the case of an error from d_splice_alias we proceed to d_add an
> inode to which we've lost our reference.  What probably needs to
> happen is that we should grab an extra reference before calling
> d_splice_alias, and we should drop it for the non error case, and for
> the error case after checking that d_splice_alias has not already done
> so.  I'll try to come up with a proposed fix.
> 
> Marc