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 a9bac27b79cbea9391ac710bb658aa37c1878268..f9f76594b866b2af919946aa50384683eed53412 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2920,12 +2920,13 @@ 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;
 }