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From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Kuniyuki Iwashima , Kuniyuki Iwashima , netdev@vger.kernel.org, "D. Wythe" , Dust Li , Sidraya Jayagond , Wenjia Zhang , Mahanta Jambigi , Tony Lu , Wen Gu , Ursula Braun Content-Type: text/plain; charset="UTF-8" smc_vlan_by_tcpsk() fetches sk_dst_get(sk)->dev before RTNL and passes it to netdev_walk_all_lower_dev(), which is illegal. Also, smc_vlan_by_tcpsk_walk() does not require RTNL at all. Let's use __sk_dst_get(), dst_dev_rcu(), and netdev_walk_all_lower_dev_rcu(). Note that the returned value of smc_vlan_by_tcpsk() is not used in the caller. Fixes: 0cfdd8f92cac ("smc: connection and link group creation") Signed-off-by: Kuniyuki Iwashima --- Cc: "D. Wythe" Cc: Dust Li Cc: Sidraya Jayagond Cc: Wenjia Zhang Cc: Mahanta Jambigi Cc: Tony Lu Cc: Wen Gu Cc: Ursula Braun --- net/smc/smc_core.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 262746e304dd..2a559a98541c 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1883,35 +1883,32 @@ static int smc_vlan_by_tcpsk_walk(struct net_device *lower_dev, /* Determine vlan of internal TCP socket. */ int smc_vlan_by_tcpsk(struct socket *clcsock, struct smc_init_info *ini) { - struct dst_entry *dst = sk_dst_get(clcsock->sk); struct netdev_nested_priv priv; struct net_device *ndev; + struct dst_entry *dst; int rc = 0; ini->vlan_id = 0; - if (!dst) { - rc = -ENOTCONN; - goto out; - } - if (!dst->dev) { + + rcu_read_lock(); + + dst = __sk_dst_get(clcsock->sk); + ndev = dst ? dst_dev_rcu(dst) : NULL; + if (!ndev) { rc = -ENODEV; - goto out_rel; + goto out; } - ndev = dst->dev; if (is_vlan_dev(ndev)) { ini->vlan_id = vlan_dev_vlan_id(ndev); - goto out_rel; + goto out; } priv.data = (void *)&ini->vlan_id; - rtnl_lock(); - netdev_walk_all_lower_dev(ndev, smc_vlan_by_tcpsk_walk, &priv); - rtnl_unlock(); - -out_rel: - dst_release(dst); + netdev_walk_all_lower_dev_rcu(ndev, smc_vlan_by_tcpsk_walk, &priv); out: + rcu_read_unlock(); + return rc; } -- 2.51.0.384.g4c02a37b29-goog