INFO: task syz-executor.3:15445 blocked for more than 143 seconds. Not tainted 5.2.0-rc5+ #41 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28128 15445 8429 0x00000004 Call Trace: context_switch kernel/sched/core.c:2818 [inline] __schedule+0x7cb/0x1560 kernel/sched/core.c:3445 schedule+0xa8/0x260 kernel/sched/core.c:3509 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:601 [inline] rwsem_down_write_failed+0x7a1/0xc60 kernel/locking/rwsem-xadd.c:633 __down_write kernel/locking/rwsem.h:227 [inline] down_write+0x93/0xa0 kernel/locking/rwsem.c:68 unregister_netdevice_notifier+0x7e/0x390 net/core/dev.c:1713 bcm_release+0x93/0x5d0 net/can/bcm.c:1525 __sock_release+0xce/0x2a0 net/socket.c:601 sock_close+0x1b/0x30 net/socket.c:1273 __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:185 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x58e/0x680 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x412fb1 Code: 80 3b 7c 0f 84 c7 02 00 00 c7 85 d0 00 00 00 00 00 00 00 48 8b 05 cf a6 24 00 49 8b 14 24 41 b9 cb 2a 44 00 48 89 ee 48 89 df <48> 85 c0 4c 0f 45 c8 45 31 c0 31 c9 e8 0e 5b 00 00 85 c0 41 89 c7 RSP: 002b:00007fff7b699000 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000412fb1 RDX: 0000000000000000 RSI: 00000000000019f7 RDI: 0000000000000006 RBP: 0000000000000001 R08: 0000000070e739fb R09: ffffffffffffffff R10: 00007fff7b6990e0 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000042a0c R15: 000000000075bf2c Showing all locks held in the system: 3 locks held by kworker/u4:1/21: 1 lock held by khungtaskd/1043: #0: 00000000e43294dc (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5149 1 lock held by rsyslogd/8292: #0: 000000004e2ccca8 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8382: #0: 00000000f03ddbd7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000083b332ae (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8383: #0: 00000000d26d20af (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000936d003b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8384: #0: 0000000054b7a2d2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000002d9f7d50 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8385: #0: 000000003629e0c9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000004867deb7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8386: #0: 000000003c000da7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f3c4105f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8387: #0: 00000000d4261f69 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000be4fad14 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8388: #0: 000000004f9f42d9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d59a7368 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/15445: #0: 00000000efc74e1e (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:778 [inline] #0: 00000000efc74e1e (&sb->s_type->i_mutex_key#11){+.+.}, at: __sock_release+0x89/0x2a0 net/socket.c:600 #1: 000000004ff660dc (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x7e/0x390 net/core/dev.c:1713 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1043 Comm: khungtaskd Not tainted 5.2.0-rc5+ #41 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+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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+0x9b7/0xec0 kernel/hung_task.c:289 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 5.2.0-rc5+ #41 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:match_held_lock+0x229/0x500 kernel/locking/lockdep.c:3884 Code: ff df 4c 89 f2 48 c1 ea 03 80 3c 02 00 0f 85 d6 02 00 00 4e 8b 24 e5 00 7a 4e 8a 49 be 00 00 00 00 00 fc ff df 4d 85 e4 75 40 <31> c0 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 83 c4 08 b8 RSP: 0018:ffff8880a9a4fa60 EFLAGS: 00000046 RAX: 0000000000000003 RBX: ffff8880a9a40e00 RCX: ffff8880a9a40e00 RDX: 0000000000000000 RSI: ffffffff88da3680 RDI: ffff8880a9a40e22 RBP: ffff8880a9a4fa90 R08: ffff8880a9a40580 R09: ffff8880a9a40e70 R10: 0000000000000000 R11: 0000000000000000 R12: ffffed10153481bf R13: ffff8880a9a40e00 R14: ffffffff88da3680 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 000000008a6bd000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:4123 [inline] lock_is_held_type+0x1b8/0x320 kernel/locking/lockdep.c:4341 lock_is_held include/linux/lockdep.h:356 [inline] ___might_sleep+0x1c4/0x280 kernel/sched/core.c:6103 get_next_corpse net/netfilter/nf_conntrack_core.c:2016 [inline] nf_ct_iterate_cleanup+0x22a/0x4e0 net/netfilter/nf_conntrack_core.c:2038 nf_conntrack_cleanup_net_list+0x7a/0x240 net/netfilter/nf_conntrack_core.c:2225 nf_conntrack_pernet_exit+0x159/0x1a0 net/netfilter/nf_conntrack_standalone.c:1151 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:168 cleanup_net+0x4e2/0xa40 net/core/net_namespace.c:575 process_one_work+0x989/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352