INFO: task syz-executor.3:9306 blocked for more than 143 seconds. Not tainted 5.2.0-rc1+ #5 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D26544 9306 3514 0x00004004 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:1717 bcm_release+0x93/0x5d0 net/can/bcm.c:1525 __sock_release+0x1f4/0x2a0 net/socket.c:607 sock_release net/socket.c:627 [inline] __sys_socketpair+0x542/0x5d0 net/socket.c:1601 __do_sys_socketpair net/socket.c:1634 [inline] __se_sys_socketpair net/socket.c:1631 [inline] __x64_sys_socketpair+0x97/0xf0 net/socket.c:1631 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: Bad RIP value. RSP: 002b:00007f5477c7dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000035 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459279 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d RBP: 000000000075bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 00007f5477c7e6d4 R13: 00000000004c7c91 R14: 00000000004ddfb0 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1041: #0: 00000000fe362dcf (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5149 1 lock held by rsyslogd/8760: #0: 0000000082fb42b2 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8850: #0: 00000000a876d4d6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000db819087 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8851: #0: 00000000127a2f65 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000b206f25f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8852: #0: 000000003a552299 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000002b82fa42 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8853: #0: 0000000069aa9c45 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000010d1a75a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8854: #0: 00000000ebf444a6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000000aa9a01e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8855: #0: 00000000f70eadae (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000045447c69 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8856: #0: 000000001df05563 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000217522f9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by kworker/1:4/8902: #0: 0000000033b973aa ((wq_completion)rcu_gp){+.+.}, at: __write_once_size include/linux/compiler.h:221 [inline] #0: 0000000033b973aa ((wq_completion)rcu_gp){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000033b973aa ((wq_completion)rcu_gp){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000033b973aa ((wq_completion)rcu_gp){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000033b973aa ((wq_completion)rcu_gp){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: 0000000033b973aa ((wq_completion)rcu_gp){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: 0000000033b973aa ((wq_completion)rcu_gp){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2240 #1: 00000000eedf7c8d ((work_completion)(&rew.rew_work)){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2244 3 locks held by kworker/u4:7/9857: #0: 000000005e640b2b (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:10083 [inline] #0: 000000005e640b2b (&rq->lock){-.-.}, at: pick_next_task_fair+0x120e/0x1990 kernel/sched/fair.c:7090 #1: 00000000fe362dcf (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:6087 #2: 0000000068672746 (&base->lock){-.-.}, at: lock_timer_base+0x56/0x1b0 kernel/time/timer.c:932 5 locks held by kworker/u4:8/23815: #0: 000000008b9e96a6 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:221 [inline] #0: 000000008b9e96a6 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000008b9e96a6 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 000000008b9e96a6 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 000000008b9e96a6 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: 000000008b9e96a6 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: 000000008b9e96a6 ((wq_completion)netns){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2240 #1: 000000005f000490 (net_cleanup_work){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2244 #2: 0000000048a4890b (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0x960 net/core/net_namespace.c:520 #3: 0000000099043270 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 #4: 00000000069647b9 (rcu_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:286 [inline] #4: 00000000069647b9 (rcu_state.exp_mutex){+.+.}, at: synchronize_rcu_expedited+0x4ab/0x5b0 kernel/rcu/tree_exp.h:790 1 lock held by syz-executor.3/9306: #0: 0000000048a4890b (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x7e/0x390 net/core/dev.c:1717 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1041 Comm: khungtaskd Not tainted 5.2.0-rc1+ #5 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 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60