INFO: task syz-executor.3:13776 blocked for more than 143 seconds. Not tainted 5.11.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.3 state:D stack:27136 pid:13776 ppid: 8448 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 rwsem_down_write_slowpath+0x7e5/0x1200 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+0x132/0x150 kernel/locking/rwsem.c:1407 unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1891 bcm_release+0x94/0x750 net/can/bcm.c:1472 __sock_release+0xcd/0x280 net/socket.c:597 sock_close+0x18/0x20 net/socket.c:1256 __fput+0x283/0x920 fs/file_table.c:280 task_work_run+0xdd/0x190 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xc5c/0x2ae0 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x427/0x20f0 kernel/signal.c:2773 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811 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+0x148/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x465d99 RSP: 002b:00007f44f319b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000004 RBX: 000000000056c0b0 RCX: 0000000000465d99 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d RBP: 00000000004bcf27 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c0b0 R13: 00007ffcbcbf47ef R14: 00007f44f319b300 R15: 0000000000022000 Showing all locks held in the system: 4 locks held by kworker/u4:4/119: 1 lock held by khungtaskd/1658: #0: ffffffff8bd73d20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6259 1 lock held by in:imklog/8135: #0: ffff888017514370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947 3 locks held by kworker/u4:6/10033: 2 locks held by syz-executor.3/13776: #0: ffff888060f3b690 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] #0: ffff888060f3b690 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:596 #1: ffffffff8d4470d0 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1891 1 lock held by syz-executor.3/14056: #0: ffffffff8d4470d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2fa/0x760 net/core/net_namespace.c:470 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1658 Comm: khungtaskd Not tainted 5.11.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 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:209 [inline] watchdog+0xd43/0xfa0 kernel/hung_task.c:294 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 119 Comm: kworker/u4:4 Not tainted 5.11.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline] RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:373 [inline] RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline] RIP: 0010:lock_acquire+0xb8/0x720 kernel/locking/lockdep.c:5413 Code: a8 7e 83 fa 07 0f 87 08 05 00 00 89 d2 be 08 00 00 00 48 89 d0 48 89 14 24 48 c1 f8 06 48 8d 3c c5 c8 d9 a3 8d e8 88 fb 5c 00 <48> 8b 14 24 48 0f a3 15 84 02 4b 0c 0f 82 a0 04 00 00 48 c7 c0 9c RSP: 0018:ffffc900012afa98 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 1ffff92000255f55 RCX: ffffffff8158d738 RDX: fffffbfff1b47b3a RSI: 0000000000000008 RDI: ffffffff8da3d9c8 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8da3d9cf R10: fffffbfff1b47b39 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8ba66c18 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c000617000 CR3: 000000001cbd3000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] nf_conntrack_lock net/netfilter/nf_conntrack_core.c:91 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:2200 [inline] nf_ct_iterate_cleanup+0x183/0x400 net/netfilter/nf_conntrack_core.c:2245 nf_conntrack_cleanup_net_list+0x81/0x250 net/netfilter/nf_conntrack_core.c:2432 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:178 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296