[PATCH 5.4 155/411] net/smc: postpone sk_refcnt increment in connect()

Greg Kroah-Hartman
2022-06-13T11:24:18Z

From: liuyacan <liuyacan@corp.netease.com>

[ 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>
---
net/smc/af_smc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index a5a8cca46bd5..394491692a07 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -877,9 +877,9 @@ 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 (schedule_work(&smc->connect_work))
smc->connect_nonblock = 1;
--
2.35.1