INFO: task syz-executor.4:18154 blocked for more than 143 seconds. Not tainted 5.1.0-rc2+ #38 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28368 18154 7620 0xa0020002 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 vhost_net_stop_vq+0x2d/0x120 drivers/vhost/net.c:1360 vhost_net_stop drivers/vhost/net.c:1374 [inline] vhost_net_release+0x5d/0x260 drivers/vhost/net.c:1406 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x90a/0x2fa0 kernel/exit.c:876 do_group_exit+0x135/0x370 kernel/exit.c:980 __do_sys_exit_group kernel/exit.c:991 [inline] __se_sys_exit_group kernel/exit.c:989 [inline] __ia32_sys_exit_group+0x44/0x50 kernel/exit.c:989 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f54869 Code: Bad RIP value. RSP: 002b:000000000845fb7c EFLAGS: 00000202 ORIG_RAX: 00000000000000fc RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000845fbdc RDX: 0000000000000001 RSI: 000000000814afd8 RDI: 00000000080a8572 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 4 locks held by kworker/u4:1/21: #0: 00000000073e858f ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 00000000073e858f ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000073e858f ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 00000000073e858f ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 00000000073e858f ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 00000000073e858f ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 00000000073e858f ((wq_completion)netns){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2240 #1: 00000000df2f806d (net_cleanup_work){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2244 #2: 000000008e33b123 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0x960 net/core/net_namespace.c:518 #3: 00000000239686b6 (rcu_state.barrier_mutex){+.+.}, at: rcu_barrier+0x30/0x270 kernel/rcu/tree.c:3197 2 locks held by kworker/u4:2/28: #0: 00000000b4c1d3f9 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1168 [inline] #0: 00000000b4c1d3f9 (&rq->lock){-.-.}, at: __schedule+0x1fc/0x1cc0 kernel/sched/core.c:3456 #1: 0000000072f7050d (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}, at: psi_dequeue kernel/sched/stats.h:100 [inline] #1: 0000000072f7050d (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}, at: dequeue_task kernel/sched/core.c:783 [inline] #1: 0000000072f7050d (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}, at: deactivate_task+0x2c4/0x3e0 kernel/sched/core.c:802 1 lock held by khungtaskd/1042: #0: 000000007193dd41 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5061 3 locks held by udevd/3875: 1 lock held by rsyslogd/7478: #0: 0000000011d6bff0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7568: #0: 000000006b32d65a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000002f627ef0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7569: #0: 00000000a96a8e83 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000076f86ee7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7570: #0: 000000006fc4ecf5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000006790127d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7571: #0: 00000000ec84b937 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000006a5ac40e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7572: #0: 000000009e642d39 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000003aefdc4a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7573: #0: 00000000b85de24c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000ec08ef01 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7574: #0: 000000003ae1f724 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000016c8baf8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/9857: #0: 000000007c4928d4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000001f245750 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/14012: #0: 00000000d47a34d9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000add2f65c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.1/4715: #0: 00000000168f7e68 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000e9f41405 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.4/18154: #0: 000000007e92658f (&vq->mutex){+.+.}, at: vhost_net_stop_vq+0x2d/0x120 drivers/vhost/net.c:1360 1 lock held by vhost-18155/18157: 1 lock held by syz-executor.2/20785: #0: 000000008e33b123 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1634 1 lock held by syz-executor.2/20790: #0: 000000008e33b123 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1634 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1042 Comm: khungtaskd Not tainted 5.1.0-rc2+ #38 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:204 [inline] watchdog+0x9b7/0xec0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: