patches/kernel/0020-lockd-lost-rollback-of-set_grace_period-in-lockd_dow.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Vasily Averin <vvs@virtuozzo.com>
   3 Date: Thu, 2 Nov 2017 13:03:42 +0300
   4 Subject: [PATCH] lockd: lost rollback of set_grace_period() in
   5  lockd_down_net()
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 Commit efda760fe95ea ("lockd: fix lockd shutdown race") is incorrect,
  11 it removes lockd_manager and disarm grace_period_end for init_net only.
  12
  13 If nfsd was started from another net namespace lockd_up_net() calls
  14 set_grace_period() that adds lockd_manager into per-netns list
  15 and queues grace_period_end delayed work.
  16
  17 These action should be reverted in lockd_down_net().
  18 Otherwise it can lead to double list_add on after restart nfsd in netns,
  19 and to use-after-free if non-disarmed delayed work will be executed after netns destroy.
  20
  21 Fixes: efda760fe95e ("lockd: fix lockd shutdown race")
  22 Cc: stable@vger.kernel.org
  23 Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
  24 Signed-off-by: J. Bruce Fields <bfields@redhat.com>
  25 (cherry picked from commit 3a2b19d1ee5633f76ae8a88da7bc039a5d1732aa)
  26 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  27 ---
  28  fs/lockd/svc.c | 2 ++
  29  1 file changed, 2 insertions(+)
  30
  31 diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
  32 index 726b6cecf430..fa8f6effcf00 100644
  33 --- a/fs/lockd/svc.c
  34 +++ b/fs/lockd/svc.c
  35 @@ -274,6 +274,8 @@ static void lockd_down_net(struct svc_serv *serv, struct net *net)
  36         if (ln->nlmsvc_users) {
  37                 if (--ln->nlmsvc_users == 0) {
  38                         nlm_shutdown_hosts_net(net);
  39 +                       cancel_delayed_work_sync(&ln->grace_period_end);
  40 +                       locks_end_grace(&ln->lockd_manager);
  41                         svc_shutdown_net(serv, net);
  42                         dprintk("lockd_down_net: per-net data destroyed; net=%p\n", net);
  43                 }