| From foo@baz Mon Apr 9 17:09:24 CEST 2018 |
| From: "J. Bruce Fields" <bfields@redhat.com> |
| Date: Tue, 28 Mar 2017 21:25:08 -0400 |
| Subject: lockd: fix lockd shutdown race |
| |
| From: "J. Bruce Fields" <bfields@redhat.com> |
| |
| |
| [ Upstream commit efda760fe95ea15291853c8fa9235c32d319cd98 ] |
| |
| As reported by David Jeffery: "a signal was sent to lockd while lockd |
| was shutting down from a request to stop nfs. The signal causes lockd |
| to call restart_grace() which puts the lockd_net structure on the grace |
| list. If this signal is received at the wrong time, it will occur after |
| lockd_down_net() has called locks_end_grace() but before |
| lockd_down_net() stops the lockd thread. This leads to lockd putting |
| the lockd_net structure back on the grace list, then exiting without |
| anything removing it from the list." |
| |
| So, perform the final locks_end_grace() from the the lockd thread; this |
| ensures it's serialized with respect to restart_grace(). |
| |
| Reported-by: David Jeffery <djeffery@redhat.com> |
| Signed-off-by: J. Bruce Fields <bfields@redhat.com> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| fs/lockd/svc.c | 6 ++++-- |
| 1 file changed, 4 insertions(+), 2 deletions(-) |
| |
| --- a/fs/lockd/svc.c |
| +++ b/fs/lockd/svc.c |
| @@ -132,6 +132,8 @@ lockd(void *vrqstp) |
| { |
| int err = 0; |
| struct svc_rqst *rqstp = vrqstp; |
| + struct net *net = &init_net; |
| + struct lockd_net *ln = net_generic(net, lockd_net_id); |
| |
| /* try_to_freeze() is called from svc_recv() */ |
| set_freezable(); |
| @@ -176,6 +178,8 @@ lockd(void *vrqstp) |
| if (nlmsvc_ops) |
| nlmsvc_invalidate_all(); |
| nlm_shutdown_hosts(); |
| + cancel_delayed_work_sync(&ln->grace_period_end); |
| + locks_end_grace(&ln->lockd_manager); |
| return 0; |
| } |
| |
| @@ -270,8 +274,6 @@ static void lockd_down_net(struct svc_se |
| if (ln->nlmsvc_users) { |
| if (--ln->nlmsvc_users == 0) { |
| nlm_shutdown_hosts_net(net); |
| - cancel_delayed_work_sync(&ln->grace_period_end); |
| - locks_end_grace(&ln->lockd_manager); |
| svc_shutdown_net(serv, net); |
| dprintk("lockd_down_net: per-net data destroyed; net=%p\n", net); |
| } |
