INFO: task syz-executor.0:19434 blocked for more than 143 seconds.
      Not tainted 5.13.0-rc2-next-20210518-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:27824 pid:19434 ppid: 12370 flags:0x00004006
Call Trace:
 context_switch kernel/sched/core.c:4688 [inline]
 __schedule+0xb38/0x58c0 kernel/sched/core.c:5945
 schedule+0xcf/0x270 kernel/sched/core.c:6024
 rwsem_down_write_slowpath+0x7dc/0x1200 kernel/locking/rwsem.c:1106
 __down_write_common kernel/locking/rwsem.c:1261 [inline]
 __down_write_common kernel/locking/rwsem.c:1258 [inline]
 __down_write kernel/locking/rwsem.c:1270 [inline]
 down_write+0x137/0x150 kernel/locking/rwsem.c:1407
 unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1949
 raw_release+0x58/0x8a0 net/can/raw.c:354
 __sock_release+0xcd/0x280 net/socket.c:599
 sock_close+0x18/0x20 net/socket.c:1258
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbfc/0x2a70 kernel/exit.c:826
 do_group_exit+0x125/0x310 kernel/exit.c:923
 get_signal+0x47f/0x2150 kernel/signal.c:2856
 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x16e/0x280 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301
 do_syscall_64+0x3e/0xb0 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
RSP: 002b:00007f63e4ca8188 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
RAX: fffffffffffffe00 RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007fffb88a554f R14: 00007f63e4ca8300 R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1628:
 #0: ffffffff8c17afe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6333
1 lock held by in:imklog/8163:
 #0: ffff888016c2c5f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
4 locks held by rs:main Q:Reg/8164:
 #0: ffff8880b9c35718 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:460
 #1: ffff8880b9c1f988 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x24c/0x670 kernel/sched/psi.c:872
 #2: ffff888035873660 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline]
 #2: ffff888035873660 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: ext4_buffered_write_iter+0xb6/0x4d0 fs/ext4/file.c:263
 #3: ffff888035873928 (&ei->i_raw_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:359 [inline]
 #3: ffff888035873928 (&ei->i_raw_lock){+.+.}-{2:2}, at: ext4_do_update_inode fs/ext4/inode.c:5033 [inline]
 #3: ffff888035873928 (&ei->i_raw_lock){+.+.}-{2:2}, at: ext4_mark_iloc_dirty+0x213/0x38d0 fs/ext4/inode.c:5724
3 locks held by kworker/u4:6/9905:
 #0: ffff88801247b138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff88801247b138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff88801247b138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff88801247b138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff88801247b138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff88801247b138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x871/0x1600 kernel/workqueue.c:2246
 #1: ffffc900168bfda8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2250
 #2: ffffffff8d897750 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 net/core/net_namespace.c:557
2 locks held by kworker/u4:1/8196:
 #0: ffff8880b9d35718 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:460
 #1: ffff8880b9d1f988 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x24c/0x670 kernel/sched/psi.c:872
2 locks held by syz-executor.0/19434:
 #0: ffff88806ac38c90 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline]
 #0: ffff88806ac38c90 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:598
 #1: ffffffff8d897750 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1949
1 lock held by syz-executor.0/21421:
 #0: ffffffff8d897750 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2f5/0x760 net/core/net_namespace.c:470
1 lock held by syz-executor.4/21423:
 #0: ffffffff8d897750 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2f5/0x760 net/core/net_namespace.c:470
1 lock held by syz-executor.2/21449:
 #0: ffffffff8d897750 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2f5/0x760 net/core/net_namespace.c:470

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

NMI backtrace for cpu 1
CPU: 1 PID: 1628 Comm: khungtaskd Not tainted 5.13.0-rc2-next-20210518-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x13e/0x1d6 lib/dump_stack.c:129
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline]
 watchdog+0xd3b/0xf50 kernel/hung_task.c:339
 kthread+0x3b1/0x4a0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x1c6/0x250 drivers/acpi/processor_idle.c:513