[PATCH 5.12 179/363] SUNRPC: Fix null pointer dereference in svc_rqst_free()

[Greg Kroah-Hartman]

From: Yunjian Wang <wangyunjian@xxxxxxxxxx>

[ Upstream commit b9f83ffaa0c096b4c832a43964fe6bff3acffe10 ]

When alloc_pages_node() returns null in svc_rqst_alloc(), the
null rq_scratch_page pointer will be dereferenced when calling
put_page() in svc_rqst_free(). Fix it by adding a null check.

Addresses-Coverity: ("Dereference after null check")
Fixes: 5191955d6fc6 ("SUNRPC: Prepare for xdr_stream-style decoding on the server-side")
Signed-off-by: Yunjian Wang <wangyunjian@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/sunrpc/svc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index d76dc9d95d16..0de918cb3d90 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -846,7 +846,8 @@ void
 svc_rqst_free(struct svc_rqst *rqstp)
 {
 	svc_release_buffer(rqstp);
-	put_page(rqstp->rq_scratch_page);
+	if (rqstp->rq_scratch_page)
+		put_page(rqstp->rq_scratch_page);
 	kfree(rqstp->rq_resp);
 	kfree(rqstp->rq_argp);
 	kfree(rqstp->rq_auth_data);
-- 
2.30.2