INFO: task syz-executor.3:12373 blocked for more than 143 seconds. Not tainted 5.9.0-rc8-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.3 state:D stack:28280 pid:12373 ppid: 11656 flags:0x80004006 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xec9/0x2280 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x137/0x150 kernel/locking/rwsem.c:1532 unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1862 raw_release+0x58/0x890 net/can/raw.c:354 __sock_release+0xcd/0x280 net/socket.c:596 sock_close+0x18/0x20 net/socket.c:1277 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0xb7d/0x29f0 kernel/exit.c:806 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45de59 Code: Bad RIP value. RSP: 002b:00007f8f76c61c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000003 RBX: 0000000000034300 RCX: 000000000045de59 RDX: 0000000000000001 RSI: 0000000000000003 RDI: 000000000000001d RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffe6b79bc2f R14: 00007f8f76c629c0 R15: 000000000118bf2c Showing all locks held in the system: 3 locks held by kworker/u4:3/44: 1 lock held by khungtaskd/1176: #0: ffffffff8a068480 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5852 1 lock held by in:imklog/6703: #0: ffff8880a17d0630 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 2 locks held by syz-executor.3/12373: #0: ffff888085a68750 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:779 [inline] #0: ffff888085a68750 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:595 #1: ffffffff8b16a190 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1862 1 lock held by syz-executor.3/12871: #0: ffffffff8b16a190 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2ac/0x5e0 net/core/net_namespace.c:479 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1176 Comm: khungtaskd Not tainted 5.9.0-rc8-syzkaller #0 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+0x198/0x1fd lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 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+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 44 Comm: kworker/u4:3 Not tainted 5.9.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:arch_local_irq_restore+0x2e/0x50 arch/x86/include/asm/paravirt.h:770 Code: 6c fc 89 53 48 89 fb 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 18 48 83 3d 21 5f a1 08 00 74 0c 48 89 df 57 9d <0f> 1f 44 00 00 5b c3 0f 0b 48 c7 c7 28 6c fc 89 e8 9d 45 5d 00 eb RSP: 0000:ffffc90000f37a50 EFLAGS: 00000286 RAX: 1ffffffff13f8d85 RBX: 0000000000000286 RCX: ffffffff815c208f RDX: dffffc0000000000 RSI: ffffffff8a0683c0 RDI: 0000000000000286 RBP: ffff8880a9186580 R08: 0000000000000000 R09: ffffffff8b5cdd0f R10: fffffbfff16b9ba1 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880a9186e88 R14: ffff8880a9186f00 R15: 0000000000000286 FS: 0000000000000000(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f96060fc000 CR3: 0000000009e8d000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held_type+0xbb/0xf0 kernel/locking/lockdep.c:5070 lock_is_held include/linux/lockdep.h:267 [inline] rcu_read_lock_sched_held+0x3a/0xb0 kernel/rcu/update.c:136 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x6a1/0x8f0 kernel/locking/lockdep.c:5040 __raw_spin_unlock include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:394 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:2220 [inline] nf_ct_iterate_cleanup+0x88/0x330 net/netfilter/nf_conntrack_core.c:2244 nf_conntrack_cleanup_net_list+0x81/0x250 net/netfilter/nf_conntrack_core.c:2431 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:604 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294