SUNRPC: Fix validity issues with rpc_pipefs sb->s_fs_info
rpc_kill_sb() must defer calling put_net() until after the notifier
has been called, since most (all?) of the notifier callbacks assume
that sb->s_fs_info points to a valid net namespace. It also must not
call put_net() if the call to rpc_fill_super was unsuccessful.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=48421
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org [>= v3.4]
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 80f5dd2..e659def 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -1152,14 +1152,19 @@
struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
mutex_lock(&sn->pipefs_sb_lock);
+ if (sn->pipefs_sb != sb) {
+ mutex_unlock(&sn->pipefs_sb_lock);
+ goto out;
+ }
sn->pipefs_sb = NULL;
mutex_unlock(&sn->pipefs_sb_lock);
- put_net(net);
dprintk("RPC: sending pipefs UMOUNT notification for net %p%s\n",
net, NET_NAME(net));
blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
RPC_PIPEFS_UMOUNT,
sb);
+ put_net(net);
+out:
kill_litter_super(sb);
}