FAILED: patch "[PATCH] svcrdma: Reject connection when transport allocation fails" failed to apply to 5.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 0944462247dcb7de7622cdaaadf5f05c52707dab
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090304-champion-prevent-c92a@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0944462247dcb7de7622cdaaadf5f05c52707dab Mon Sep 17 00:00:00 2001
From: Chuck Lever <cel@kernel.org>
Date: Wed, 27 May 2026 11:00:14 -0400
Subject: [PATCH] svcrdma: Reject connection when transport allocation fails

handle_connect_req() returns without action when
svc_rdma_create_xprt() fails to allocate the new transport.
The CM core returns 0 for CONNECT_REQUEST events, so it does
not destroy the new rdma_cm_id. Each allocation failure under
memory pressure leaks one rdma_cm_id, and a remote peer driving
connection attempts can amplify this.

Reject the connection by returning a non-zero status from the
CM event handler, which tells the CM core to destroy the
orphaned cm_id.

Fixes: 377f9b2f4529 ("rdma: SVCRDMA Core Transport Services")
Cc: stable@vger.kernel.org
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260527-rdma-follow-on-v1-4-1b09bd87b6cd@oracle.com
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 63dbf16dbe7f..656b2bd258a9 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -246,12 +246,16 @@ svc_rdma_parse_connect_private(struct svcxprt_rdma *newxprt,
  * structure for the listening endpoint.
  *
  * This function creates a new xprt for the new connection and enqueues it on
- * the accept queue for the listent xprt. When the listen thread is kicked, it
+ * the accept queue for the listen xprt. When the listen thread is kicked, it
  * will call the recvfrom method on the listen xprt which will accept the new
  * connection.
+ *
+ * Return values:
+ *     %0: Do not destroy @new_cma_id
+ *     %1: Destroy @new_cma_id (allocation failure)
  */
-static void handle_connect_req(struct rdma_cm_id *new_cma_id,
-			       struct rdma_conn_param *param)
+static int handle_connect_req(struct rdma_cm_id *new_cma_id,
+			      struct rdma_conn_param *param)
 {
 	struct svcxprt_rdma *listen_xprt = new_cma_id->context;
 	struct svcxprt_rdma *newxprt;
@@ -261,7 +265,7 @@ static void handle_connect_req(struct rdma_cm_id *new_cma_id,
 				       listen_xprt->sc_xprt.xpt_net,
 				       ibdev_to_node(new_cma_id->device));
 	if (!newxprt)
-		return;
+		return 1;
 	newxprt->sc_cm_id = new_cma_id;
 	new_cma_id->context = newxprt;
 	svc_rdma_parse_connect_private(newxprt, param);
@@ -295,6 +299,7 @@ static void handle_connect_req(struct rdma_cm_id *new_cma_id,
 
 	set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
 	svc_xprt_enqueue(&listen_xprt->sc_xprt);
+	return 0;
 }
 
 /**
@@ -318,8 +323,7 @@ static int svc_rdma_listen_handler(struct rdma_cm_id *cma_id,
 
 	switch (event->event) {
 	case RDMA_CM_EVENT_CONNECT_REQUEST:
-		handle_connect_req(cma_id, &event->param.conn);
-		break;
+		return handle_connect_req(cma_id, &event->param.conn);
 	case RDMA_CM_EVENT_ADDR_CHANGE:
 		listen_id = svc_rdma_create_listen_id(cma_rdma->xpt_net,
 						      sap, cma_xprt);