From: Myungho Jung <mhjungk@gmail.com>
To: Ursula Braun <ubraun@linux.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>,
linux-s390@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v3] net/smc: fix TCP fallback socket release
Date: Tue, 18 Dec 2018 09:02:25 -0800 [thread overview]
Message-ID: <20181218170221.GA21835@myunghoj-Precision-5530> (raw)
clcsock can be released while kernel_accept() references it in TCP
listen worker. Also, clcsock needs to wake up before released if TCP
fallback is used and the clcsock is blocked by accept. Add a lock to
safely release clcsock and call kernel_sock_shutdown() to wake up
clcsock from accept in smc_release().
Reported-by: syzbot+0bf2e01269f1274b4b03@syzkaller.appspotmail.com
Reported-by: syzbot+e3132895630f957306bc@syzkaller.appspotmail.com
Signed-off-by: Myungho Jung <mhjungk@gmail.com>
---
net/smc/af_smc.c | 14 ++++++++++++--
net/smc/smc.h | 4 ++++
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 5fbaf1901571..82cb0e5634bc 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -147,8 +147,14 @@ static int smc_release(struct socket *sock)
sk->sk_shutdown |= SHUTDOWN_MASK;
}
if (smc->clcsock) {
+ if (smc->use_fallback && sk->sk_state == SMC_LISTEN) {
+ /* wake up clcsock accept */
+ rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
+ }
+ mutex_lock(&smc->clcsock_release_lock);
sock_release(smc->clcsock);
smc->clcsock = NULL;
+ mutex_unlock(&smc->clcsock_release_lock);
}
if (smc->use_fallback) {
if (sk->sk_state != SMC_LISTEN && sk->sk_state != SMC_INIT)
@@ -205,6 +211,7 @@ static struct sock *smc_sock_alloc(struct net *net, struct socket *sock,
spin_lock_init(&smc->conn.send_lock);
sk->sk_prot->hash(sk);
sk_refcnt_debug_inc(sk);
+ mutex_init(&smc->clcsock_release_lock);
return sk;
}
@@ -821,7 +828,7 @@ static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_smc)
struct socket *new_clcsock = NULL;
struct sock *lsk = &lsmc->sk;
struct sock *new_sk;
- int rc;
+ int rc = -EINVAL;
release_sock(lsk);
new_sk = smc_sock_alloc(sock_net(lsk), NULL, lsk->sk_protocol);
@@ -834,7 +841,10 @@ static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_smc)
}
*new_smc = smc_sk(new_sk);
- rc = kernel_accept(lsmc->clcsock, &new_clcsock, 0);
+ mutex_lock(&lsmc->clcsock_release_lock);
+ if (lsmc->clcsock)
+ rc = kernel_accept(lsmc->clcsock, &new_clcsock, 0);
+ mutex_unlock(&lsmc->clcsock_release_lock);
lock_sock(lsk);
if (rc < 0)
lsk->sk_err = -rc;
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 08786ace6010..5721416d0605 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -219,6 +219,10 @@ struct smc_sock { /* smc sock container */
* started, waiting for unsent
* data to be sent
*/
+ struct mutex clcsock_release_lock;
+ /* protects clcsock of a listen
+ * socket
+ * */
};
static inline struct smc_sock *smc_sk(const struct sock *sk)
--
2.17.1
next reply other threads:[~2018-12-18 17:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 17:02 Myungho Jung [this message]
2018-12-19 6:03 ` [PATCH v3] net/smc: fix TCP fallback socket release David Miller
2019-01-04 6:54 Myungho Jung
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