From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ding Tianhong Subject: [PATCH 2/2] tipc: avoid possible deadlock while remove disc_timeout() Date: Thu, 8 Aug 2013 18:45:19 +0800 Message-ID: <520376BF.7080906@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: Jon Maloy , Allan Stephens , "David S. Miller" , Netdev , Return-path: Received: from szxga02-in.huawei.com ([119.145.14.65]:24217 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757726Ab3HHKph (ORCPT ); Thu, 8 Aug 2013 06:45:37 -0400 Sender: netdev-owner@vger.kernel.org List-ID: We met lockdep warning when enable and disable the bearer for commands such as: tipc-config -netid=1234 -addr=1.1.3 -be=eth:eth0 tipc-config -netid=1234 -addr=1.1.3 -bd=eth:eth0 [ 327.693472] [ 327.693595] ====================================================== [ 327.693994] [ INFO: possible circular locking dependency detected ] [ 327.694519] 3.11.0-rc3-wwd-default #4 Tainted: G O [ 327.694882] ------------------------------------------------------- [ 327.695385] tipc-config/5825 is trying to acquire lock: [ 327.695754] (((timer))#2){+.-...}, at: [] del_timer_sync+0x0/0xd0 [ 327.696018] [ 327.696018] but task is already holding lock: [ 327.696018] (&(&b_ptr->lock)->rlock){+.-...}, at: [] bearer_disable+0xdd/0x120 [tipc] [ 327.696018] [ 327.696018] which lock already depends on the new lock. [ 327.696018] [ 327.696018] [ 327.696018] the existing dependency chain (in reverse order) is: [ 327.696018] [ 327.696018] -> #1 (&(&b_ptr->lock)->rlock){+.-...}: [ 327.696018] [] validate_chain+0x6dd/0x870 [ 327.696018] [] __lock_acquire+0x3db/0x670 [ 327.696018] [] lock_acquire+0x103/0x130 [ 327.696018] [] _raw_spin_lock_bh+0x41/0x80 [ 327.696018] [] disc_timeout+0x18/0xd0 [tipc] [ 327.696018] [] call_timer_fn+0xda/0x1e0 [ 327.696018] [] run_timer_softirq+0x2a7/0x2d0 [ 327.696018] [] __do_softirq+0x16a/0x2e0 [ 327.696018] [] irq_exit+0xd5/0xe0 [ 327.696018] [] smp_apic_timer_interrupt+0x45/0x60 [ 327.696018] [] apic_timer_interrupt+0x6f/0x80 [ 327.696018] [] arch_cpu_idle+0x1e/0x30 [ 327.696018] [] cpu_idle_loop+0x1fd/0x280 [ 327.696018] [] cpu_startup_entry+0x1e/0x20 [ 327.696018] [] start_secondary+0x89/0x90 [ 327.696018] [ 327.696018] -> #0 (((timer))#2){+.-...}: [ 327.696018] [] check_prev_add+0x43e/0x4b0 [ 327.696018] [] validate_chain+0x6dd/0x870 [ 327.696018] [] __lock_acquire+0x3db/0x670 [ 327.696018] [] lock_acquire+0x103/0x130 [ 327.696018] [] del_timer_sync+0x3d/0xd0 [ 327.696018] [] tipc_disc_delete+0x15/0x30 [tipc] [ 327.696018] [] bearer_disable+0xef/0x120 [tipc] [ 327.696018] [] tipc_disable_bearer+0x2f/0x60 [tipc] [ 327.696018] [] tipc_cfg_do_cmd+0x2e2/0x550 [tipc] [ 327.696018] [] handle_cmd+0x49/0xe0 [tipc] [ 327.696018] [] genl_family_rcv_msg+0x268/0x340 [ 327.696018] [] genl_rcv_msg+0x70/0xd0 [ 327.696018] [] netlink_rcv_skb+0x89/0xb0 [ 327.696018] [] genl_rcv+0x27/0x40 [ 327.696018] [] netlink_unicast+0x15e/0x1b0 [ 327.696018] [] netlink_sendmsg+0x22f/0x400 [ 327.696018] [] __sock_sendmsg+0x66/0x80 [ 327.696018] [] sock_aio_write+0x107/0x120 [ 327.696018] [] do_sync_write+0x7d/0xc0 [ 327.696018] [] vfs_write+0x186/0x190 [ 327.696018] [] SyS_write+0x60/0xb0 [ 327.696018] [] system_call_fastpath+0x16/0x1b [ 327.696018] [ 327.696018] other info that might help us debug this: [ 327.696018] [ 327.696018] Possible unsafe locking scenario: [ 327.696018] [ 327.696018] CPU0 CPU1 [ 327.696018] ---- ---- [ 327.696018] lock(&(&b_ptr->lock)->rlock); [ 327.696018] lock(((timer))#2); [ 327.696018] lock(&(&b_ptr->lock)->rlock); [ 327.696018] lock(((timer))#2); [ 327.696018] [ 327.696018] *** DEADLOCK *** [ 327.696018] [ 327.696018] 5 locks held by tipc-config/5825: [ 327.696018] #0: (cb_lock){++++++}, at: [] genl_rcv+0x18/0x40 [ 327.696018] #1: (genl_mutex){+.+.+.}, at: [] genl_rcv_msg+0xa6/0xd0 [ 327.696018] #2: (config_mutex){+.+.+.}, at: [] tipc_cfg_do_cmd+0x39/0x550 [tipc] [ 327.696018] #3: (tipc_net_lock){++.-..}, at: [] tipc_disable_bearer+0x18/0x60 [tipc] [ 327.696018] #4: (&(&b_ptr->lock)->rlock){+.-...}, at: [] bearer_disable+0xdd/0x120 [tipc] [ 327.696018] [ 327.696018] stack backtrace: [ 327.696018] CPU: 2 PID: 5825 Comm: tipc-config Tainted: G O 3.11.0-rc3-wwd-default #4 [ 327.696018] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 327.696018] 00000000ffffffff ffff880037fa77a8 ffffffff814d03dd 0000000000000000 [ 327.696018] ffff880037fa7808 ffff880037fa77e8 ffffffff810b1c4f 0000000037fa77e8 [ 327.696018] ffff880037fa7808 ffff880037e4db40 0000000000000000 ffff880037e4e318 [ 327.696018] Call Trace: [ 327.696018] [] dump_stack+0x4d/0xa0 [ 327.696018] [] print_circular_bug+0x10f/0x120 [ 327.696018] [] check_prev_add+0x43e/0x4b0 [ 327.696018] [] validate_chain+0x6dd/0x870 [ 327.696018] [] ? sched_clock_cpu+0xd8/0x110 [ 327.696018] [] __lock_acquire+0x3db/0x670 [ 327.696018] [] lock_acquire+0x103/0x130 [ 327.696018] [] ? try_to_del_timer_sync+0x70/0x70 [ 327.696018] [] del_timer_sync+0x3d/0xd0 [ 327.696018] [] ? try_to_del_timer_sync+0x70/0x70 [ 327.696018] [] tipc_disc_delete+0x15/0x30 [tipc] [ 327.696018] [] bearer_disable+0xef/0x120 [tipc] [ 327.696018] [] tipc_disable_bearer+0x2f/0x60 [tipc] [ 327.696018] [] tipc_cfg_do_cmd+0x2e2/0x550 [tipc] [ 327.696018] [] ? security_capable+0x13/0x20 [ 327.696018] [] handle_cmd+0x49/0xe0 [tipc] [ 327.696018] [] genl_family_rcv_msg+0x268/0x340 [ 327.696018] [] genl_rcv_msg+0x70/0xd0 [ 327.696018] [] ? genl_lock+0x20/0x20 [ 327.696018] [] netlink_rcv_skb+0x89/0xb0 [ 327.696018] [] ? genl_rcv+0x18/0x40 [ 327.696018] [] genl_rcv+0x27/0x40 [ 327.696018] [] netlink_unicast+0x15e/0x1b0 [ 327.696018] [] ? memcpy_fromiovec+0x6c/0x90 [ 327.696018] [] netlink_sendmsg+0x22f/0x400 [ 327.696018] [] __sock_sendmsg+0x66/0x80 [ 327.696018] [] sock_aio_write+0x107/0x120 [ 327.696018] [] ? release_sock+0x8c/0xa0 [ 327.696018] [] do_sync_write+0x7d/0xc0 [ 327.696018] [] ? rw_verify_area+0x54/0x100 [ 327.696018] [] vfs_write+0x186/0x190 [ 327.696018] [] SyS_write+0x60/0xb0 [ 327.696018] [] system_call_fastpath+0x16/0x1b Signed-off-by: Wang Weidong Signed-off-by: Ding Tianhong --- net/tipc/bearer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 7687211..9dc8c84 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -461,22 +461,22 @@ static void bearer_disable(struct tipc_bearer *b_ptr) struct tipc_link *l_ptr; struct tipc_link *temp_l_ptr; struct list_head list; + struct tipc_link_req *temp_req; pr_info("Disabling bearer <%s>\n", b_ptr->name); spin_lock_bh(&b_ptr->lock); b_ptr->blocked = 1; b_ptr->media->disable_bearer(b_ptr); list_replace_init(&b_ptr->links, &list); + temp_req = b_ptr->link_req; spin_unlock_bh(&b_ptr->lock); list_for_each_entry_safe(l_ptr, temp_l_ptr, &list, link_list) { tipc_link_delete(l_ptr); } - spin_lock_bh(&b_ptr->lock); - if (b_ptr->link_req) - tipc_disc_delete(b_ptr->link_req); - spin_unlock_bh(&b_ptr->lock); + if (temp_req) + tipc_disc_delete(temp_req); memset(b_ptr, 0, sizeof(struct tipc_bearer)); } -- 1.8.2.1