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 fb801c2..2ddd7b3 100644 (file)
--- 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;