| Message ID | CAHA+R7PAyR_cJ9_9nfUBc0U9o-U=gCV+sN_VYbHwgq-QdoEVzQ@mail.gmail.com |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index d3929a6..eb50b9a 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -77,10 +77,11 @@ static inline void __tunnel_dst_set(struct ip_tunnel_dst *idst, dst = NULL; spin_lock_bh(&idst->lock); - old_dst = rcu_dereference(idst->dst); + old_dst = idst->dst; rcu_assign_pointer(idst->dst, dst); - dst_release(old_dst); spin_unlock_bh(&idst->lock); + synchronize_rcu(); + dst_release(old_dst); }
Hi, Tom I saw: [ 65.609535] [ INFO: suspicious RCU usage. ] [ 65.609537] 3.13.0-rc6+ #139 Not tainted [ 65.609538] ------------------------------- [ 65.609539] net/ipv4/ip_tunnel.c:80 suspicious rcu_dereference_check() usage! [ 65.609540] [ 65.609540] other info that might help us debug this: [ 65.609540] [ 65.609541] [ 65.609541] rcu_scheduler_active = 1, debug_locks = 0 [ 65.609542] 5 locks held by kworker/u8:0/6: [ 65.609553] #0: (%s#4){.+.+.+}, at: [<ffffffff8106d56b>] process_one_work+0x173/0x41e [ 65.609557] #1: (net_cleanup_work){+.+.+.}, at: [<ffffffff8106d56b>] process_one_work+0x173/0x41e [ 65.609563] #2: (net_mutex){+.+.+.}, at: [<ffffffff817816c9>] cleanup_net+0x85/0x18a [ 65.609569] #3: (rtnl_mutex){+.+.+.}, at: [<ffffffff81796058>] rtnl_lock+0x17/0x19 [ 65.609575] #4: (&(&idst->lock)->rlock){+.....}, at: [<ffffffff818820fe>] __tunnel_dst_set+0x30/0x8b [ 65.609575] [ 65.609575] stack backtrace: [ 65.609577] CPU: 1 PID: 6 Comm: kworker/u8:0 Not tainted 3.13.0-rc6+ #139 [ 65.609579] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 65.609582] Workqueue: netns cleanup_net [ 65.609585] 0000000000000000 ffff880118205bb0 ffffffff819894b6 ffff8801181ea550 [ 65.609587] ffff880118205be0 ffffffff81095f34 0000000000000000 ffffe8ffff606df0 [ 65.609589] ffffe8ffff606df8 0000000000000000 ffff880118205c10 ffffffff8188213c [ 65.609590] Call Trace: [ 65.609595] [<ffffffff819894b6>] dump_stack+0x4d/0x66 [ 65.609598] [<ffffffff81095f34>] lockdep_rcu_suspicious+0x107/0x110 [ 65.609600] [<ffffffff8188213c>] __tunnel_dst_set+0x6e/0x8b [ 65.609602] [<ffffffff81882203>] tunnel_dst_reset_all.isra.25+0x40/0x47 [ 65.609605] [<ffffffff81883e28>] ip_tunnel_uninit+0x61/0x64 [ 65.609608] [<ffffffff8178aeb2>] rollback_registered_many+0x188/0x21f [ 65.609610] [<ffffffff8178b02f>] unregister_netdevice_many+0x19/0x63 [ 65.609612] [<ffffffff81883a17>] ip_tunnel_delete_net+0xd1/0xe5 [ 65.609615] [<ffffffff8188bc68>] vti_exit_net+0x2a/0x2c [ 65.609617] [<ffffffff81780f21>] ops_exit_list+0x44/0x55 [ 65.609619] [<ffffffff8178173a>] cleanup_net+0xf6/0x18a [ 65.609621] [<ffffffff8106d612>] process_one_work+0x21a/0x41e [ 65.609623] [<ffffffff8106d56b>] ? process_one_work+0x173/0x41e [ 65.609625] [<ffffffff8106dc1b>] worker_thread+0x149/0x1f5 [ 65.609628] [<ffffffff8106dad2>] ? rescuer_thread+0x28d/0x28d [ 65.609630] [<ffffffff81073f6f>] kthread+0xd2/0xda [ 65.609634] [<ffffffff8107d0ed>] ? finish_task_switch+0x3a/0xbe [ 65.609636] [<ffffffff81073e9d>] ? __kthread_parkme+0x61/0x61 [ 65.609640] [<ffffffff819961ac>] ret_from_fork+0x7c/0xb0 [ 65.609642] [<ffffffff81073e9d>] ? __kthread_parkme+0x61/0x61 I think the patch below could fix it but not sure if we really need synchronize_rcu() here... static inline void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html