Messages in this thread |  | | From | Xin Long <> | Date | Mon, 13 Aug 2018 23:39:43 +0800 | Subject | Re: possible deadlock in flush_work (3) |
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On Mon, Aug 13, 2018 at 8:35 PM, syzbot <syzbot+a8371264572a6872b8a3@syzkaller.appspotmail.com> wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: d6dd6431591b Merge branch 'fixes' of git://git.kernel.org/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=14e800aa400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=152cb8ccd35b1f70 > dashboard link: https://syzkaller.appspot.com/bug?extid=a8371264572a6872b8a3 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+a8371264572a6872b8a3@syzkaller.appspotmail.com > > 8021q: adding VLAN 0 to HW filter on device bond0 > > ====================================================== > WARNING: possible circular locking dependency detected > 4.18.0-rc8+ #185 Not tainted > ------------------------------------------------------ > syz-executor2/6421 is trying to acquire lock: > 00000000209b4e4b ((wq_completion)bond_dev->name){+.+.}, at: start_flush_work > kernel/workqueue.c:2888 [inline] > 00000000209b4e4b ((wq_completion)bond_dev->name){+.+.}, at: > flush_work+0x4b8/0x900 kernel/workqueue.c:2917 > > but task is already holding lock: > 00000000f0f3d47a (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 > net/core/rtnetlink.c:77 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #2 (rtnl_mutex){+.+.}: > __mutex_lock_common kernel/locking/mutex.c:757 [inline] > __mutex_lock+0x176/0x1820 kernel/locking/mutex.c:894 > mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:909 > rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77 > bond_netdev_notify drivers/net/bonding/bond_main.c:1310 [inline] > bond_netdev_notify_work+0x44/0xd0 > drivers/net/bonding/bond_main.c:1320 > process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153 > worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 > kthread+0x345/0x410 kernel/kthread.c:246 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: > process_one_work+0xc0b/0x1ba0 kernel/workqueue.c:2129 > worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 > kthread+0x345/0x410 kernel/kthread.c:246 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > -> #0 ((wq_completion)bond_dev->name){+.+.}: > lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924 > start_flush_work kernel/workqueue.c:2889 [inline] > flush_work+0x4dd/0x900 kernel/workqueue.c:2917 > __cancel_work_timer+0x4bd/0x830 kernel/workqueue.c:2989 > cancel_delayed_work_sync+0x1a/0x20 kernel/workqueue.c:3121 > bond_work_cancel_all drivers/net/bonding/bond_main.c:3318 [inline] > bond_close+0x1b/0x130 drivers/net/bonding/bond_main.c:3381 > __dev_close_many+0x21e/0x380 net/core/dev.c:1476 > __dev_close net/core/dev.c:1488 [inline] > __dev_change_flags+0x38d/0x9c0 net/core/dev.c:6989 > dev_change_flags+0x89/0x150 net/core/dev.c:7060 > dev_ifsioc+0x84f/0xb30 net/core/dev_ioctl.c:237 > dev_ioctl+0x1b5/0xcc0 net/core/dev_ioctl.c:493 > sock_do_ioctl+0x1d3/0x3e0 net/socket.c:993 > sock_ioctl+0x30d/0x680 net/socket.c:1094 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:500 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 > __do_sys_ioctl fs/ioctl.c:708 [inline] > __se_sys_ioctl fs/ioctl.c:706 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > other info that might help us debug this: > > Chain exists of: > (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) > --> rtnl_mutex > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(rtnl_mutex); > lock((work_completion)(&(&nnw->work)->work)); > lock(rtnl_mutex); > lock((wq_completion)bond_dev->name); nnw->work is queuing up into bond->wq, so it seems bond_netdev_notify() should have used rtnl_trylock() instead of rtnl_lock(), as do other delayed_work handlers in bond->wq.
> > *** DEADLOCK *** > > 1 lock held by syz-executor2/6421: > #0: 00000000f0f3d47a (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 > net/core/rtnetlink.c:77 > > stack backtrace: > CPU: 0 PID: 6421 Comm: syz-executor2 Not tainted 4.18.0-rc8+ #185 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 > print_circular_bug.isra.36.cold.57+0x1bd/0x27d > kernel/locking/lockdep.c:1227 > check_prev_add kernel/locking/lockdep.c:1867 [inline] > check_prevs_add kernel/locking/lockdep.c:1980 [inline] > validate_chain kernel/locking/lockdep.c:2421 [inline] > __lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3435 > lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924 > start_flush_work kernel/workqueue.c:2889 [inline] > flush_work+0x4dd/0x900 kernel/workqueue.c:2917 > __cancel_work_timer+0x4bd/0x830 kernel/workqueue.c:2989 > cancel_delayed_work_sync+0x1a/0x20 kernel/workqueue.c:3121 > bond_work_cancel_all drivers/net/bonding/bond_main.c:3318 [inline] > bond_close+0x1b/0x130 drivers/net/bonding/bond_main.c:3381 > __dev_close_many+0x21e/0x380 net/core/dev.c:1476 > __dev_close net/core/dev.c:1488 [inline] > __dev_change_flags+0x38d/0x9c0 net/core/dev.c:6989 > dev_change_flags+0x89/0x150 net/core/dev.c:7060 > dev_ifsioc+0x84f/0xb30 net/core/dev_ioctl.c:237 > dev_ioctl+0x1b5/0xcc0 net/core/dev_ioctl.c:493 > sock_do_ioctl+0x1d3/0x3e0 net/socket.c:993 > kernel msg: ebtables bug: please report to author: Wrong nr of counters > sock_ioctl+0x30d/0x680 net/socket.c:1094 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:500 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 > __do_sys_ioctl fs/ioctl.c:708 [inline] > __se_sys_ioctl fs/ioctl.c:706 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x457089 > Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007fee7b2ccc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007fee7b2cd6d4 RCX: 0000000000457089 > RDX: 0000000020000140 RSI: 0000000000008914 RDI: 0000000000000004 > RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000004d19e0 R14: 00000000004c7454 R15: 0000000000000000 > 8021q: adding VLAN 0 to HW filter on device bond0 > (unnamed net_device) (uninitialized): option miimon: invalid value > (18446744073709551615) > (unnamed net_device) (uninitialized): option miimon: allowed values 0 - > 2147483647 > (unnamed net_device) (uninitialized): option miimon: invalid value > (18446744073709551615) > (unnamed net_device) (uninitialized): option miimon: allowed values 0 - > 2147483647 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > device bond0 left promiscuous mode > IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > 8021q: adding VLAN 0 to HW filter on device bond0 > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot.
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