INFO: task syz-executor.5:13837 blocked for more than 143 seconds. Not tainted 5.3.0-rc3+ #138 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28160 13837 8751 0x00000004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x755/0x1580 kernel/sched/core.c:3880 schedule+0xa8/0x270 kernel/sched/core.c:3944 rwsem_down_write_slowpath+0x708/0xf60 kernel/locking/rwsem.c:1214 __down_write kernel/locking/rwsem.c:1365 [inline] down_write+0x13c/0x150 kernel/locking/rwsem.c:1501 unregister_netdevice_notifier+0x7e/0x390 net/core/dev.c:1713 raw_release+0x57/0x700 net/can/raw.c:354 __sock_release+0xce/0x280 net/socket.c:590 sock_close+0x1e/0x30 net/socket.c:1268 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x413511 Code: 8c d6 65 00 ba 02 00 00 00 bf 28 38 44 00 ff 15 7d a1 24 00 85 c0 0f 85 37 fe ff ff 31 c9 31 f6 41 b9 b0 20 41 00 41 b8 90 d6 <65> 00 ba 03 00 00 00 bf 31 38 44 00 ff 15 55 a1 24 00 85 c0 0f 85 RSP: 002b:00007ffcb5bbacb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000413511 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 0000000000000001 R08: 00000000f5520e6f R09: 00000000f8103863 R10: 00007ffcb5bbad90 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000760e30 R15: ffffffffffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1057: #0: 00000000628e3df3 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5256 1 lock held by rsyslogd/8609: #0: 000000000c27ef0d (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8699: #0: 0000000028108626 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: 000000001acf0f4c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8700: #0: 000000004ef6fea4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000390f331d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8701: #0: 00000000fc87e487 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000d37c7684 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8702: #0: 0000000003f31ddf (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: 000000000a2ccec7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8703: #0: 00000000c4dc0273 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000619688ec (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8704: #0: 00000000cf34d5bd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000179f1501 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8705: #0: 000000004bd32341 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: 0000000078599f84 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:14/9361: 2 locks held by syz-executor.5/13837: #0: 000000006a3dc00b (&sb->s_type->i_mutex_key#12){+.+.}, at: inode_lock include/linux/fs.h:778 [inline] #0: 000000006a3dc00b (&sb->s_type->i_mutex_key#12){+.+.}, at: __sock_release+0x89/0x280 net/socket.c:589 #1: 000000006d7bde8b (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x7e/0x390 net/core/dev.c:1713 1 lock held by syz-executor.1/13912: #0: 000000006d7bde8b (pernet_ops_rwsem){++++}, at: copy_net_ns+0x26d/0x41f net/core/net_namespace.c:471 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1057 Comm: khungtaskd Not tainted 5.3.0-rc3+ #138 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0x9d0/0xef0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9361 Comm: kworker/u4:14 Not tainted 5.3.0-rc3+ #138 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:match_held_lock+0x10/0x510 kernel/locking/lockdep.c:3938 Code: 80 f4 d2 88 89 45 84 e8 3e 9a 54 00 8b 45 84 e9 67 ff ff ff 66 0f 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 57 <41> 56 41 55 41 54 53 48 89 fb 48 83 c7 10 48 89 fa 48 83 ec 08 48 RSP: 0018:ffff888060657a88 EFLAGS: 00000093 RAX: dffffc0000000000 RBX: ffff88806064c140 RCX: ffff88806064c9d0 RDX: 0000000000000000 RSI: ffffffff88dac2c0 RDI: ffff88806064c9f8 RBP: ffff888060657a90 R08: 1ffffffff14a9141 R09: fffffbfff14a9142 R10: fffffbfff14a9141 R11: ffffffff8a548a0f R12: ffffed100c0c9939 R13: ffff88806064c9f8 R14: ffffffff88dac2c0 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c424d1f000 CR3: 000000008d5ad000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:4233 [inline] lock_is_held_type+0x1b8/0x320 kernel/locking/lockdep.c:4450 lock_is_held include/linux/lockdep.h:365 [inline] ___might_sleep+0x201/0x280 kernel/sched/core.c:6570 get_next_corpse net/netfilter/nf_conntrack_core.c:2015 [inline] nf_ct_iterate_cleanup+0x22a/0x4e0 net/netfilter/nf_conntrack_core.c:2037 nf_conntrack_cleanup_net_list+0x7a/0x240 net/netfilter/nf_conntrack_core.c:2224 nf_conntrack_pernet_exit+0x159/0x1a0 net/netfilter/nf_conntrack_standalone.c:1149 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:175 cleanup_net+0x4e2/0xa70 net/core/net_namespace.c:594 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352