--- /dev/null
+From 880a88f318cf1d2a0f4c0a7ff7b07e2062b434a4 Mon Sep 17 00:00:00 2001
+From: David Howells <dhowells@redhat.com>
+Date: Tue, 8 Jul 2025 22:15:04 +0100
+Subject: rxrpc: Fix oops due to non-existence of prealloc backlog struct
+
+From: David Howells <dhowells@redhat.com>
+
+commit 880a88f318cf1d2a0f4c0a7ff7b07e2062b434a4 upstream.
+
+If an AF_RXRPC service socket is opened and bound, but calls are
+preallocated, then rxrpc_alloc_incoming_call() will oops because the
+rxrpc_backlog struct doesn't get allocated until the first preallocation is
+made.
+
+Fix this by returning NULL from rxrpc_alloc_incoming_call() if there is no
+backlog struct. This will cause the incoming call to be aborted.
+
+Reported-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com>
+Suggested-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com>
+Signed-off-by: David Howells <dhowells@redhat.com>
+cc: LePremierHomme <kwqcheii@proton.me>
+cc: Marc Dionne <marc.dionne@auristor.com>
+cc: Willy Tarreau <w@1wt.eu>
+cc: Simon Horman <horms@kernel.org>
+cc: linux-afs@lists.infradead.org
+Link: https://patch.msgid.link/20250708211506.2699012-3-dhowells@redhat.com
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/rxrpc/call_accept.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/net/rxrpc/call_accept.c
++++ b/net/rxrpc/call_accept.c
+@@ -254,6 +254,9 @@ static struct rxrpc_call *rxrpc_alloc_in
+ unsigned short call_tail, conn_tail, peer_tail;
+ unsigned short call_count, conn_count;
+
++ if (!b)
++ return NULL;
++
+ /* #calls >= #conns >= #peers must hold true. */
+ call_head = smp_load_acquire(&b->call_backlog_head);
+ call_tail = b->call_backlog_tail;