INFO: task syz-executor.0:28269 blocked for more than 143 seconds. Not tainted 5.6.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D26760 28269 9038 0x80004006 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x7c9/0xc50 kernel/sched/core.c:4080 schedule+0x188/0x220 kernel/sched/core.c:4154 rwsem_down_write_slowpath+0x7d0/0xd60 kernel/locking/rwsem.c:1238 hlock_class kernel/locking/lockdep.c:175 [inline] __lock_acquire+0xc21/0x1bc0 kernel/locking/lockdep.c:3951 __down_write kernel/locking/rwsem.c:1392 [inline] down_write+0x125/0x130 kernel/locking/rwsem.c:1535 unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484 inode_lock include/linux/fs.h:792 [inline] __sock_release net/socket.c:604 [inline] sock_close+0x94/0x260 net/socket.c:1283 bcm_release+0x77/0x800 net/can/bcm.c:1474 atomic64_set include/asm-generic/atomic-instrumented.h:854 [inline] atomic_long_set include/asm-generic/atomic-long.h:40 [inline] rwsem_set_owner kernel/locking/rwsem.c:177 [inline] __down_write kernel/locking/rwsem.c:1394 [inline] down_write+0xcd/0x130 kernel/locking/rwsem.c:1535 __sock_release net/socket.c:605 [inline] sock_close+0xd8/0x260 net/socket.c:1283 sock_mmap+0x90/0x90 net/socket.c:1278 __fput+0x2d8/0x730 fs/file_table.c:280 task_work_run+0x176/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x5ef/0x1f80 kernel/exit.c:801 do_group_exit+0x15e/0x2c0 kernel/exit.c:899 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x1f/0x80 kernel/locking/spinlock.c:199 get_signal+0x13cf/0x1d60 kernel/signal.c:2739 alloc_file+0x86/0x4b0 fs/file_table.c:197 do_signal+0x33/0x610 arch/x86/kernel/signal.c:813 rcu_read_unlock_sched include/linux/rcupdate.h:732 [inline] __fd_install+0x251/0x490 fs/file.c:613 exit_to_usermode_loop arch/x86/entry/common.c:160 [inline] prepare_exit_to_usermode+0x32a/0x600 arch/x86/entry/common.c:195 syscall_return_slowpath+0xf9/0x420 arch/x86/entry/common.c:277 entry_SYSCALL_64_after_hwframe+0x49/0xbe Showing all locks held in the system: 1 lock held by khungtaskd/1128: #0: ffffffff890d9ac8 (rcu_read_lock){....}, at: rcu_lock_acquire+0x0/0x30 lib/xarray.c:75 1 lock held by rsyslogd/8910: #0: ffff88809324fba0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:826 2 locks held by getty/9000: #0: ffff8880980d4090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc9000180b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x25d/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/9001: #0: ffff888098aee090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x25d/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/9002: #0: ffff8880a26a3090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x25d/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/9003: #0: ffff88809f9b8090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017db2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x25d/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/9004: #0: ffff8880a26a2090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017bb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x25d/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/9005: #0: ffff88809efaa090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x25d/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/9006: #0: ffff8880a30c5090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc9000172b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x25d/0x1bc0 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:4/20844: #0: ffff8880a9b73d28 ((wq_completion)netns){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff8880a9b73d28 ((wq_completion)netns){+.+.}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2239 #1: ffffc90001667d88 (net_cleanup_work){+.+.}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2241 #2: ffffffff8938ef68 (pernet_ops_rwsem){++++}, at: cleanup_net+0xac/0xb80 net/core/net_namespace.c:551 2 locks held by syz-executor.0/28269: #0: ffff888092043c80 (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:792 [inline] #0: ffff888092043c80 (&sb->s_type->i_mutex_key#11){+.+.}, at: __sock_release net/socket.c:604 [inline] #0: ffff888092043c80 (&sb->s_type->i_mutex_key#11){+.+.}, at: sock_close+0x94/0x260 net/socket.c:1283 #1: ffffffff8938ef68 (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1128 Comm: khungtaskd Not tainted 5.6.0-rc6-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+0x1e9/0x30e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 arch_trigger_cpumask_backtrace+0x10/0x10 arch/x86/kernel/apic/hw_nmi.c:38 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd2a/0xd40 kernel/hung_task.c:289 kthread+0x317/0x340 kernel/kthread.c:255 hungtask_pm_notify+0x50/0x50 kernel/hung_task.c:265 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1234 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 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60