From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Tue, 2 Aug 2022 15:48:50 -0400
Subject: [PATCH] NFSv4/pnfs: Fix a use-after-free bug in open
Git-commit: 2135e5d56278ffdb1c2e6d325dc6b87f669b9dac
Patch-mainline: v6.0
References: git-fixes

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>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/nfs4proc.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3116,12 +3116,13 @@ static int _nfs4_open_and_get_state(stru
 	}
 
 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;
 }