net/smc: Fix sock leak when release after smc_shutdown()

[ Upstream commit 1a74e99323746353bba11562a2f2d0aa8102f402 ]

Since commit e5d5aadcf3cd ("net/smc: fix sk_refcnt underflow on linkdown
and fallback"), for a fallback connection, __smc_release() does not call
sock_put() if its state is already SMC_CLOSED.

When calling smc_shutdown() after falling back, its state is set to
SMC_CLOSED but does not call sock_put(), so this patch calls it.

Reported-and-tested-by: syzbot+6e29a053eb165bd50de5@syzkaller.appspotmail.com
Fixes: e5d5aadcf3cd ("net/smc: fix sk_refcnt underflow on linkdown and fallback")
Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.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 fa8897497dcc9e6c9d28ad8be950dbf2ab57f891..499058248bdb850c17676e6abbaf05acc3567e1b 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2332,8 +2332,10 @@ static int smc_shutdown(struct socket *sock, int how)
        if (smc->use_fallback) {
                rc = kernel_sock_shutdown(smc->clcsock, how);
                sk->sk_shutdown = smc->clcsock->sk->sk_shutdown;
-               if (sk->sk_shutdown == SHUTDOWN_MASK)
+               if (sk->sk_shutdown == SHUTDOWN_MASK) {
                        sk->sk_state = SMC_CLOSED;
+                       sock_put(sk);
+               }
                goto out;
        }
        switch (how) {