From: liuyacan <liuyacan@corp.netease.com>
Date: Mon, 23 May 2022 04:57:07 +0000 (+0800)
Subject: net/smc: postpone sk_refcnt increment in connect()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8eb0e5a2659cf7793b675173cbdf9f6ea2be458f;p=linux.git

net/smc: postpone sk_refcnt increment in connect()

[ Upstream commit 75c1edf23b95a9c66923d9269d8e86e4dbde151f ]

Same trigger condition as commit 86434744. When setsockopt runs
in parallel to a connect(), and switch the socket into fallback
mode. Then the sk_refcnt is incremented in smc_connect(), but
its state stay in SMC_INIT (NOT SMC_ACTIVE). This cause the
corresponding sk_refcnt decrement in __smc_release() will not be
performed.

Fixes: 86434744fedf ("net/smc: add fallback check to connect()")
Signed-off-by: liuyacan <liuyacan@corp.netease.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index fb801c249d923..2ddd7b34b4ce5 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1283,9 +1283,9 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr,
 	if (rc && rc != -EINPROGRESS)
 		goto out;
 
-	sock_hold(&smc->sk); /* sock put in passive closing */
 	if (smc->use_fallback)
 		goto out;
+	sock_hold(&smc->sk); /* sock put in passive closing */
 	if (flags & O_NONBLOCK) {
 		if (queue_work(smc_hs_wq, &smc->connect_work))
 			smc->connect_nonblock = 1;