NFSv4/pnfs: Fix a use-after-free bug in open

commit 2135e5d56278ffdb1c2e6d325dc6b87f669b9dac upstream.

If someone cancels the open RPC call, then we must not try to free
either the open slot or the layoutget operation arguments, since they
are likely still in use by the hung RPC call.

Fixes: 6949493884fe ("NFSv4: Don't hold the layoutget locks across multiple RPC calls")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index a93b408e7d3c8b244a99b1a6c1c8006dea333e1c..a808763c52c1942046c2287d9c3f44f0cf907808 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3106,12 +3106,13 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
        }
 
 out:
-       if (opendata->lgp) {
-               nfs4_lgopen_release(opendata->lgp);
-               opendata->lgp = NULL;
-       }
-       if (!opendata->cancelled)
+       if (!opendata->cancelled) {
+               if (opendata->lgp) {
+                       nfs4_lgopen_release(opendata->lgp);
+                       opendata->lgp = NULL;
+               }
                nfs4_sequence_free_slot(&opendata->o_res.seq_res);
+       }
        return ret;
 }