[PATCH 5.10 20/86] net/smc: Fix sock leak when release after smc_shutdown()

Greg Kroah-Hartman
2022-04-26T08:48:49Z

From: Tony Lu <tonylu@linux.alibaba.com>

[ 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>
---
net/smc/af_smc.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 4f16d406ad8e..1b98f3241150 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2144,8 +2144,10 @@ 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) {
--
2.35.1