possible deadlock in flush_work (3)

From: syzbot
Date: Mon Aug 13 2018 - 08:35:07 EST

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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@xxxxxxxxxxxxxxxxxxxxxxxxx

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);

*** 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

---
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Next message: Alan Cox: "Re: [RFC net-next 00/15] net: A socket API for LoRa"
Previous message: Chao Yu: "Re: [PATCH 2/8] staging: erofs: separate erofs_get_meta_page"
Next in thread: Xin Long: "Re: possible deadlock in flush_work (3)"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]