net/smc: move sock lock in smc_ioctl()

When an SMC socket is connecting it is decided whether fallback to TCP is needed. To avoid races between connect and ioctl move the sock lock before the use_fallback check. Reported-by: [email protected] Reported-by: [email protected] Fixes: 1992d99 ("net/smc: take sock lock in smc_ioctl()") Signed-off-by: Ursula Braun <[email protected]> Signed-off-by: David S. Miller <[email protected]>
chewitt · Aug 9, 2018 · 7311d66 · 7311d66
1 parent bd58c7e
commit 7311d66
Showing 1 changed file with 7 additions and 3 deletions.
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
@@ -1522,12 +1522,16 @@ static int smc_ioctl(struct socket *sock, unsigned int cmd,
 
 	smc = smc_sk(sock->sk);
 	conn = &smc->conn;
+	lock_sock(&smc->sk);
 	if (smc->use_fallback) {
-		if (!smc->clcsock)
+		if (!smc->clcsock) {
+			release_sock(&smc->sk);
 			return -EBADF;
-		return smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg);
+		}
+		answ = smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg);
+		release_sock(&smc->sk);
+		return answ;
 	}
-	lock_sock(&smc->sk);
 	switch (cmd) {
 	case SIOCINQ: /* same as FIONREAD */
 		if (smc->sk.sk_state == SMC_LISTEN) {