2009-10-14 21:58:37

by Trond Myklebust

[permalink] [raw]
Subject: Re: [pnfs] [PATCH 1/1] nfs41: resolve some race conditions with queued SEQUENCE operations when unmounting

On Wed, 2009-10-14 at 17:53 -0400, Trond Myklebust wrote:
> On Wed, 2009-10-14 at 14:50 -0700, Alexandros Batsakis wrote:
> > a) nfs41_sequence_done() called after destroy_session() that leads to
> > a NULL pointer dereference
> > b) a BADSESSION reply to a sequence operation triggers a
> > reset_session() at the same time with destroy_session() (called by
> > umount) that leads to another NULL pointer dereference.
>
> This would mean that nfs41_sequence_done is being called _after_ the
> nfs_client (and hence the session) has been destroyed. That sounds like
> the real bug that needs to be fixed.

Correction: it means that nfs41_sequence_done is being called after the
superblock that "owns" those rpc calls has been destroyed. (Which is a
bug... :-))

Cheers
Trond