On Thu, Jun 5, 2008 at 1:35 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > On Thu, 5 Jun 2008 00:33:54 +0100 > "Daniel J Blueman" <daniel.blueman@xxxxxxxxx> wrote: > >> Having experienced 'mount.nfs4: internal error' when mounting nfsv4 in >> the past, I have a minimal test-case I sometimes run: >> >> $ while :; do mount -t nfs4 filer:/store /store; umount /store; done >> >> After ~100 iterations, I saw the 'mount.nfs4: internal error', >> followed by symptoms of memory corruption [1], a locking issue with >> the reporting [2] and another (related?) memory-corruption issue >> (off-by-1?) [3]. A little analysis shows memory being overwritten by >> (likely) a poison value, which gets complicated if it's not >> use-after-free... >> >> Anyone dare confirm this issue? NFSv4 server is x86-64 Ubuntu 8.04 >> 2.6.24-18, client U8.04 2.6.26-rc4; batteries included [4]. >> >> I'm happy to decode addresses, test patches etc. >> >> Daniel >> > > Looks like it fell down while trying to take down the kthread during a > failed mount attempt. I have to wonder if I might have introduced a > race when I changed nfs4 callback thread to kthread API. I think we may > need the BKL around the last 2 statements in the main callback thread > function. If you can easily reproduce this, could you test the > following patch and let me know if it helps? > > Note that this patch is entirely untested, so test it someplace > non-critical ;-). > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > > diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c > index c1e7c83..a3e83f9 100644 > --- a/fs/nfs/callback.c > +++ b/fs/nfs/callback.c > @@ -90,9 +90,9 @@ nfs_callback_svc(void *vrqstp) > preverr = err; > svc_process(rqstp); > } > - unlock_kernel(); > nfs_callback_info.task = NULL; > svc_exit_thread(rqstp); > + unlock_kernel(); > return 0; > } This doesn't resolve the issue, alas. I'll hunker down to the bisection in the next few days. Thanks, Daniel -- Daniel J Blueman -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
