Subject: [PATCH net v2 2/3] espintcp: use datagram_poll_queue for socket readiness

From: Ralf Lici <[email-masked]>
Date: Mon, 20 Oct 2025 09:37:30 +0200

espintcp uses a custom queue (ike_queue) to deliver packets to
userspace. The polling logic relies on datagram_poll, which checks
sk_receive_queue, which can lead to false readiness signals when that
queue contains non-userspace packets.

Switch espintcp_poll to use datagram_poll_queue with ike_queue, ensuring
poll only signals readiness when userspace data is actually available.

Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Ralf Lici <[email-masked]>
---
 net/xfrm/espintcp.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/net/xfrm/espintcp.c b/net/xfrm/espintcp.c
index fc7a603b04f1..bf744ac9d5a7 100644
--- a/net/xfrm/espintcp.c
+++ b/net/xfrm/espintcp.c
@@ -555,14 +555,10 @@ static void espintcp_close(struct sock *sk, long timeout)
 static __poll_t espintcp_poll(struct file *file, struct socket *sock,
 			      poll_table *wait)
 {
-	__poll_t mask = datagram_poll(file, sock, wait);
 	struct sock *sk = sock->sk;
 	struct espintcp_ctx *ctx = espintcp_getctx(sk);
 
-	if (!skb_queue_empty(&ctx->ike_queue))
-		mask |= EPOLLIN | EPOLLRDNORM;
-
-	return mask;
+	return datagram_poll_queue(file, sock, wait, &ctx->ike_queue);
 }
 
 static void build_protos(struct proto *espintcp_prot,
-- 
2.51.0