From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konstantin Khlebnikov Subject: [PATCH v3 4/5] ipvlan: use rcu_deference_bh() in ipvlan_queue_xmit() Date: Tue, 14 Jul 2015 16:35:54 +0300 Message-ID: <20150714133554.22448.46602.stgit@buzz> References: <20150714132941.22448.42175.stgit@buzz> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Jiri Benc To: linux-netdev , Mahesh Bandewar Return-path: Received: from forward-corp1f.mail.yandex.net ([95.108.130.40]:59166 "EHLO forward-corp1f.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752880AbbGNNf5 (ORCPT ); Tue, 14 Jul 2015 09:35:57 -0400 In-Reply-To: <20150714132941.22448.42175.stgit@buzz> Sender: netdev-owner@vger.kernel.org List-ID: From: WANG Cong In tx path rcu_read_lock_bh() is held, so we need rcu_deference_bh(). This fixes the following warning: =============================== [ INFO: suspicious RCU usage. ] 4.1.0-rc1+ #1007 Not tainted ------------------------------- drivers/net/ipvlan/ipvlan.h:106 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 1 lock held by dhclient/1076: #0: (rcu_read_lock_bh){......}, at: [] rcu_lock_acquire+0x0/0x26 stack backtrace: CPU: 2 PID: 1076 Comm: dhclient Not tainted 4.1.0-rc1+ #1007 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 0000000000000001 ffff8800d381bac8 ffffffff81a4154f 000000003c1a3c19 ffff8800d4d0a690 ffff8800d381baf8 ffffffff810b849f ffff880117d41148 ffff880117d40000 ffff880117d40068 0000000000000156 ffff8800d381bb18 Call Trace: [] dump_stack+0x4c/0x65 [] lockdep_rcu_suspicious+0x107/0x110 [] ipvlan_port_get_rcu+0x47/0x4e [] ipvlan_queue_xmit+0x35/0x450 [] ? rcu_read_unlock+0x3e/0x5f [] ? local_clock+0x19/0x22 [] ? __lock_is_held+0x39/0x52 [] ipvlan_start_xmit+0x1b/0x44 [] dev_hard_start_xmit+0x2ae/0x467 [] __dev_queue_xmit+0x50a/0x60c [] dev_queue_xmit_sk+0x13/0x15 [] dev_queue_xmit+0x10/0x12 [] packet_sendmsg+0xb6b/0xbdf [] ? mark_lock+0x2e/0x226 [] ? sched_clock_cpu+0x9e/0xb7 [] sock_sendmsg_nosec+0x12/0x1d [] sock_sendmsg+0x29/0x2e [] sock_write_iter+0x70/0x91 [] __vfs_write+0x7e/0xa7 [] vfs_write+0x92/0xe8 [] SyS_write+0x47/0x7e [] system_call_fastpath+0x12/0x6f Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.") Cc: Mahesh Bandewar Signed-off-by: Cong Wang Acked-by: Mahesh Bandewar Acked-by: Konstantin Khlebnikov --- drivers/net/ipvlan/ipvlan.h | 5 +++++ drivers/net/ipvlan/ipvlan_core.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h index 40f9d7e4a0ea..9542b7bac61a 100644 --- a/drivers/net/ipvlan/ipvlan.h +++ b/drivers/net/ipvlan/ipvlan.h @@ -104,6 +104,11 @@ static inline struct ipvl_port *ipvlan_port_get_rcu(const struct net_device *d) return rcu_dereference(d->rx_handler_data); } +static inline struct ipvl_port *ipvlan_port_get_rcu_bh(const struct net_device *d) +{ + return rcu_dereference_bh(d->rx_handler_data); +} + static inline struct ipvl_port *ipvlan_port_get_rtnl(const struct net_device *d) { return rtnl_dereference(d->rx_handler_data); diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c index 8f8628a0adba..207f62e8de9a 100644 --- a/drivers/net/ipvlan/ipvlan_core.c +++ b/drivers/net/ipvlan/ipvlan_core.c @@ -529,7 +529,7 @@ static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev) int ipvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev) { struct ipvl_dev *ipvlan = netdev_priv(dev); - struct ipvl_port *port = ipvlan_port_get_rcu(ipvlan->phy_dev); + struct ipvl_port *port = ipvlan_port_get_rcu_bh(ipvlan->phy_dev); if (!port) goto out;