INFO: task hung in crda_timeout_work

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 0376d5dce0aa Merge git://git.kernel.org/pub/scm/linux/kern..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=15db162a400000
kernel config: https://syzkaller.appspot.com/x/.config?x=b8f349d23d3c4835
dashboard link: https://syzkaller.appspot.com/bug?extid=8a558e9e5f74380e6e43
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [christia...@ubuntu.com da...@davemloft.net
dsa...@gmail.com f...@strlen.de jakub.k...@netronome.com
jb...@redhat.com ktk...@virtuozzo.com linux-...@vger.kernel.org
lucie...@gmail.com net...@vger.kernel.org nicolas...@6wind.com]

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+8a558e...@syzkaller.appspotmail.com

INFO: task kworker/1:1:24 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/1:1 D21272 24 2 0x80000000
Workqueue: events_power_efficient crda_timeout_work
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
crda_timeout_work+0x1d/0x50 net/wireless/reg.c:511
process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153
worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
kthread+0x35a/0x420 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
INFO: task kworker/u4:3:142 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:3 D13704 142 2 0x80000000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
exp_funnel_lock kernel/rcu/tree_exp.h:320 [inline]
_synchronize_rcu_expedited+0xc68/0xfd0 kernel/rcu/tree_exp.h:667
synchronize_rcu_expedited+0x35/0xb0 kernel/rcu/tree_exp.h:795
synchronize_net+0x3b/0x60 net/core/dev.c:9012
rollback_registered_many+0xd38/0x1240 net/core/dev.c:7983
unregister_netdevice_many+0xfa/0x4c0 net/core/dev.c:9057
ip6_tnl_exit_batch_net+0x54d/0x790 net/ipv6/ip6_tunnel.c:2268
ops_exit_list.isra.7+0x105/0x160 net/core/net_namespace.c:156
cleanup_net+0x555/0xb10 net/core/net_namespace.c:551
process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153
worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
kthread+0x35a/0x420 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
INFO: task syz-executor0:13865 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0 D25400 13865 5348 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
dev_ioctl+0x68b/0xcc0 net/core/dev_ioctl.c:512
sock_ioctl+0x484/0x690 net/socket.c:1008
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f85b522bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f85b522c6d4 RCX: 00000000004572d9
RDX: 0000000020000080 RSI: 00000000000089f0 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d26d0 R14: 00000000004c7bd7 R15: 0000000000000000
INFO: task syz-executor5:13869 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5 D24808 13869 5347 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
sock_do_ioctl+0x2f4/0x420 net/socket.c:963
sock_ioctl+0x313/0x690 net/socket.c:1074
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f6f901a5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6f901a66d4 RCX: 00000000004572d9
RDX: 0000000020000280 RSI: 0000000000008912 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cdd08 R14: 00000000004c43c4 R15: 0000000000000000
INFO: task syz-executor5:13872 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5 D25352 13872 5347 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
sock_do_ioctl+0x2f4/0x420 net/socket.c:963
sock_ioctl+0x313/0x690 net/socket.c:1074
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f6f90184c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6f901856d4 RCX: 00000000004572d9
RDX: 0000000020000280 RSI: 0000000000008912 RDI: 0000000000000005
RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cdd08 R14: 00000000004c43c4 R15: 0000000000000001
INFO: task syz-executor1:13875 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1 D24968 13875 5351 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
sock_do_ioctl+0x2f4/0x420 net/socket.c:963
sock_ioctl+0x313/0x690 net/socket.c:1074
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f39bcb1bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f39bcb1c6d4 RCX: 00000000004572d9
RDX: 0000000020000280 RSI: 0000000000008912 RDI: 0000000000000005
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cdd08 R14: 00000000004c43c4 R15: 0000000000000000
INFO: task syz-executor1:13881 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1 D24616 13881 5351 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
sock_do_ioctl+0x2f4/0x420 net/socket.c:963
sock_ioctl+0x313/0x690 net/socket.c:1074
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f39bcafac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f39bcafb6d4 RCX: 00000000004572d9
RDX: 0000000020000280 RSI: 0000000000008912 RDI: 0000000000000008
RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cdd08 R14: 00000000004c43c4 R15: 0000000000000001
INFO: task syz-executor4:13891 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4 D25400 13891 5350 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
sock_do_ioctl+0x2f4/0x420 net/socket.c:963
sock_ioctl+0x313/0x690 net/socket.c:1074
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f60fb02ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f60fb02f6d4 RCX: 00000000004572d9
RDX: 0000000020000280 RSI: 0000000000008912 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cdd08 R14: 00000000004c43c4 R15: 0000000000000000
INFO: task syz-executor4:13898 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4 D24616 13898 5350 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
sock_do_ioctl+0x2f4/0x420 net/socket.c:963
sock_ioctl+0x313/0x690 net/socket.c:1074
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f60fb00dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f60fb00e6d4 RCX: 00000000004572d9
RDX: 0000000020000280 RSI: 0000000000008912 RDI: 0000000000000005
RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cdd08 R14: 00000000004c43c4 R15: 0000000000000001
INFO: task syz-executor2:13897 blocked for more than 140 seconds.
Not tainted 4.19.0-rc3+ #101
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2 D24792 13897 5349 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2825 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
schedule+0xfe/0x460 kernel/sched/core.c:3517
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbfb/0x1710 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
rtnl_lock net/core/rtnetlink.c:77 [inline]
rtnetlink_rcv_msg+0x40e/0xc20 net/core/rtnetlink.c:4712
netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2454
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4733
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x5a5/0x760 net/netlink/af_netlink.c:1343
netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1908
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: Bad RIP value.
RSP: 002b:00007f9791863c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f97918646d4 RCX: 00000000004572d9
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d4b60 R14: 00000000004c90ab R15: 0000000000000000

Showing all locks held in the system:
3 locks held by kworker/1:0/19:
#0: 000000004bcf8051 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
__write_once_size include/linux/compiler.h:215 [inline]
#0: 000000004bcf8051 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 000000004bcf8051 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
#0: 000000004bcf8051 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
#0: 000000004bcf8051 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
set_work_data kernel/workqueue.c:617 [inline]
#0: 000000004bcf8051 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
#0: 000000004bcf8051 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124
#1: 000000006748439d ((addr_chk_work).work){+.+.}, at:
process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128
#2: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
3 locks held by kworker/1:1/24:
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
__write_once_size include/linux/compiler.h:215 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
set_work_data kernel/workqueue.c:617 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124
#1: 000000008bf9b439 ((crda_timeout).work){+.+.}, at:
process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128
#2: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
4 locks held by kworker/u4:3/142:
#0: 00000000bc14f36b ((wq_completion)"%s""netns"){+.+.}, at:
__write_once_size include/linux/compiler.h:215 [inline]
#0: 00000000bc14f36b ((wq_completion)"%s""netns"){+.+.}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 00000000bc14f36b ((wq_completion)"%s""netns"){+.+.}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:40 [inline]
#0: 00000000bc14f36b ((wq_completion)"%s""netns"){+.+.}, at:
atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
#0: 00000000bc14f36b ((wq_completion)"%s""netns"){+.+.}, at: set_work_data
kernel/workqueue.c:617 [inline]
#0: 00000000bc14f36b ((wq_completion)"%s""netns"){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
#0: 00000000bc14f36b ((wq_completion)"%s""netns"){+.+.}, at:
process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124
#1: 000000001ef2d33e (net_cleanup_work){+.+.}, at:
process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128
#2: 00000000c099855d (pernet_ops_rwsem){++++}, at: cleanup_net+0x13f/0xb10
net/core/net_namespace.c:518
#3: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by khungtaskd/985:
#0: 000000008d0a808d (rcu_read_lock){....}, at:
debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4436
1 lock held by rsyslogd/5214:
#0: 0000000013f4b204 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200
fs/file.c:766
2 locks held by getty/5304:
#0: 0000000095928384 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000099e1c46 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5305:
#0: 000000000175a6a9 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000ab5b3a1a (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5306:
#0: 00000000fd41691c (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000567e7be6 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5307:
#0: 00000000d0e803e9 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000efae0a1f (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5308:
#0: 0000000049ef7b05 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000532ab7c5 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5309:
#0: 00000000837a93a1 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 0000000084459434 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5310:
#0: 0000000092657293 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 000000008944cfb3 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
3 locks held by kworker/1:3/5658:
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
__write_once_size include/linux/compiler.h:215 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
set_work_data kernel/workqueue.c:617 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
#0: 00000000430855cf ((wq_completion)"events_power_efficient"){+.+.}, at:
process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124
#1: 0000000082cd5f0d ((reg_check_chans).work){+.+.}, at:
process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128
#2: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor0/13865:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor5/13869:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor5/13872:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor1/13875:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor1/13881:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor4/13891:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor4/13898:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20
net/core/rtnetlink.c:77
1 lock held by syz-executor2/13897:
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnl_lock
net/core/rtnetlink.c:77 [inline]
#0: 00000000cf0004cd (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x40e/0xc20
net/core/rtnetlink.c:4712

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 985 Comm: khungtaskd Not tainted 4.19.0-rc3+ #101
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+0x1c4/0x2b4 lib/dump_stack.c:113
nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1b3/0x1ed lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:144 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline]
watchdog+0xb3e/0x1050 kernel/hung_task.c:265
kthread+0x35a/0x420 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10
arch/x86/include/asm/irqflags.h:57


---
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Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.