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Message-Id: <1431456403-20070-1-git-send-email-xiyou.wangcong@gmail.com>
Date: Tue, 12 May 2015 11:46:43 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: Cong Wang <xiyou.wangcong@...il.com>,
Mahesh Bandewar <maheshb@...gle.com>
Subject: [Patch net] ipvlan: use rcu_deference_bh() in ipvlan_queue_xmit()
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: [<ffffffff817e8d84>] 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:
[<ffffffff81a4154f>] dump_stack+0x4c/0x65
[<ffffffff810b849f>] lockdep_rcu_suspicious+0x107/0x110
[<ffffffff8165a522>] ipvlan_port_get_rcu+0x47/0x4e
[<ffffffff8165ad14>] ipvlan_queue_xmit+0x35/0x450
[<ffffffff817ea45d>] ? rcu_read_unlock+0x3e/0x5f
[<ffffffff810a20bf>] ? local_clock+0x19/0x22
[<ffffffff810b4781>] ? __lock_is_held+0x39/0x52
[<ffffffff8165b64c>] ipvlan_start_xmit+0x1b/0x44
[<ffffffff817edf7f>] dev_hard_start_xmit+0x2ae/0x467
[<ffffffff817ee642>] __dev_queue_xmit+0x50a/0x60c
[<ffffffff817ee7a7>] dev_queue_xmit_sk+0x13/0x15
[<ffffffff81997596>] dev_queue_xmit+0x10/0x12
[<ffffffff8199b41c>] packet_sendmsg+0xb6b/0xbdf
[<ffffffff810b5ea7>] ? mark_lock+0x2e/0x226
[<ffffffff810a1fcc>] ? sched_clock_cpu+0x9e/0xb7
[<ffffffff817d56f9>] sock_sendmsg_nosec+0x12/0x1d
[<ffffffff817d7257>] sock_sendmsg+0x29/0x2e
[<ffffffff817d72cc>] sock_write_iter+0x70/0x91
[<ffffffff81199563>] __vfs_write+0x7e/0xa7
[<ffffffff811996bc>] vfs_write+0x92/0xe8
[<ffffffff811997d7>] SyS_write+0x47/0x7e
[<ffffffff81a4d517>] system_call_fastpath+0x12/0x6f
Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Cc: Mahesh Bandewar <maheshb@...gle.com>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
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 54549a6..0799442 100644
--- a/drivers/net/ipvlan/ipvlan.h
+++ b/drivers/net/ipvlan/ipvlan.h
@@ -102,6 +102,11 @@ 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 c30b5c3..b349dad 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -507,7 +507,7 @@ 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;
--
1.8.3.1
--
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