INFO: task syz-executor.0:6387 blocked for more than 143 seconds. Not tainted 5.7.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28552 6387 405 0x80004006 Call Trace: context_switch kernel/sched/core.c:3367 [inline] __schedule+0x892/0x1d80 kernel/sched/core.c:4083 locks_remove_posix+0x277/0x4e0 fs/locks.c:2706 __sched_text_start+0x8/0x8 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] prepare_to_wait_event+0x129/0x650 kernel/sched/wait.c:305 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x39/0x40 kernel/locking/spinlock.c:191 schedule+0xcd/0x2b0 kernel/sched/core.c:4158 wdm_flush+0x2ea/0x3c0 drivers/usb/class/cdc-wdm.c:590 wdm_poll+0x280/0x280 include/linux/poll.h:50 finish_wait+0x260/0x260 include/linux/list.h:301 task_work_add+0x97/0x120 kernel/task_work.c:35 wdm_poll+0x280/0x280 include/linux/poll.h:50 filp_close+0xb4/0x170 fs/open.c:1251 close_files fs/file.c:388 [inline] put_files_struct fs/file.c:416 [inline] put_files_struct+0x1d8/0x2e0 fs/file.c:413 exit_files+0x7e/0xa0 fs/file.c:445 do_exit+0xb36/0x2c80 kernel/exit.c:791 find_held_lock+0x2d/0x110 kernel/locking/lockdep.c:4458 mm_update_next_owner+0x7a0/0x7a0 kernel/exit.c:375 lock_downgrade+0x720/0x720 kernel/locking/lockdep.c:4599 do_group_exit+0x125/0x340 kernel/exit.c:894 get_signal+0x480/0x2480 kernel/signal.c:2739 schedule_timeout_idle+0x80/0x80 kernel/time/timer.c:1942 do_signal+0x88/0x1ae0 arch/x86/kernel/signal.c:784 free_object+0x5/0x70 lib/debugobjects.c:429 destroy_hrtimer_on_stack kernel/time/hrtimer.c:453 [inline] hrtimer_nanosleep+0x211/0x3a0 kernel/time/hrtimer.c:1947 nanosleep_copyout+0x100/0x100 kernel/time/hrtimer.c:1861 force_valid_ss arch/x86/kernel/signal.c:73 [inline] restore_sigcontext+0x620/0x620 arch/x86/kernel/signal.c:134 hrtimer_init_sleeper_on_stack+0x90/0x90 kernel/time/hrtimer.c:1833 put_old_itimerspec32+0x1d0/0x1d0 kernel/time/time.c:908 __sched_text_start+0x8/0x8 __do_sys_nanosleep kernel/time/hrtimer.c:1962 [inline] __se_sys_nanosleep kernel/time/hrtimer.c:1953 [inline] __x64_sys_nanosleep+0x1ed/0x260 kernel/time/hrtimer.c:1953 hrtimer_nanosleep+0x3a0/0x3a0 kernel/time/hrtimer.c:1943 exit_to_usermode_loop+0x1a2/0x200 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x4e0/0x5a0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 INFO: task syz-executor.1:6460 blocked for more than 143 seconds. Not tainted 5.7.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28816 6460 399 0x80004006 Call Trace: context_switch kernel/sched/core.c:3367 [inline] __schedule+0x892/0x1d80 kernel/sched/core.c:4083 locks_remove_posix+0x277/0x4e0 fs/locks.c:2706 __sched_text_start+0x8/0x8 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] prepare_to_wait_event+0x129/0x650 kernel/sched/wait.c:305 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x39/0x40 kernel/locking/spinlock.c:191 schedule+0xcd/0x2b0 kernel/sched/core.c:4158 wdm_flush+0x2ea/0x3c0 drivers/usb/class/cdc-wdm.c:590 wdm_poll+0x280/0x280 include/linux/poll.h:50 finish_wait+0x260/0x260 include/linux/list.h:301 task_work_add+0x97/0x120 kernel/task_work.c:35 wdm_poll+0x280/0x280 include/linux/poll.h:50 filp_close+0xb4/0x170 fs/open.c:1251 close_files fs/file.c:388 [inline] put_files_struct fs/file.c:416 [inline] put_files_struct+0x1d8/0x2e0 fs/file.c:413 exit_files+0x7e/0xa0 fs/file.c:445 do_exit+0xb36/0x2c80 kernel/exit.c:791 find_held_lock+0x2d/0x110 kernel/locking/lockdep.c:4458 mm_update_next_owner+0x7a0/0x7a0 kernel/exit.c:375 lock_downgrade+0x720/0x720 kernel/locking/lockdep.c:4599 do_group_exit+0x125/0x340 kernel/exit.c:894 get_signal+0x480/0x2480 kernel/signal.c:2739 find_held_lock+0x2d/0x110 kernel/locking/lockdep.c:4458 __might_fault mm/memory.c:4814 [inline] __might_fault+0x11f/0x1d0 mm/memory.c:4799 do_signal+0x88/0x1ae0 arch/x86/kernel/signal.c:784 __might_fault mm/memory.c:4814 [inline] __might_fault+0x190/0x1d0 mm/memory.c:4799 force_valid_ss arch/x86/kernel/signal.c:73 [inline] restore_sigcontext+0x620/0x620 arch/x86/kernel/signal.c:134 _copy_to_user+0x126/0x160 lib/usercopy.c:31 __do_sys_futex kernel/futex.c:3869 [inline] __se_sys_futex kernel/futex.c:3837 [inline] __x64_sys_futex+0x380/0x4f0 kernel/futex.c:3837 do_futex+0x1ae0/0x1ae0 include/linux/list.h:70 __do_sys_clock_gettime kernel/time/posix-timers.c:1094 [inline] __se_sys_clock_gettime kernel/time/posix-timers.c:1082 [inline] __x64_sys_clock_gettime+0x165/0x240 kernel/time/posix-timers.c:1082 exit_to_usermode_loop+0x1a2/0x200 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x4e0/0x5a0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: ffffffff87111260 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5754 1 lock held by in:imklog/285: #0: ffff8881c94205f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by agetty/299: #0: ffff8881d4f1a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900009ee2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x220/0x1b30 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.7.0-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+0xef/0x16e lib/dump_stack.c:118 irq_force_complete_move.cold+0x13/0x47 arch/x86/kernel/apic/vector.c:1023 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 lapic_can_unplug_cpu.cold+0x3b/0x3b nmi_trigger_cpumask_backtrace+0x1db/0x207 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa99/0xfd0 kernel/hung_task.c:289 reset_hung_task_detector+0x30/0x30 kernel/hung_task.c:243 kthread+0x326/0x430 kernel/kthread.c:268 kthread_create_on_node+0xf0/0xf0 kernel/kthread.c:405 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.7.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x60 kernel/kcov.c:197 Code: cc 65 48 8b 04 25 40 0f 02 00 48 8b 80 20 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 65 48 8b 04 25 40 0f 02 00 <65> 8b 15 e8 cf c1 7e f7 c2 00 01 1f 00 48 8b 34 24 74 0f 80 e6 01 RSP: 0018:ffff8881da257cc8 EFLAGS: 00000203 RAX: ffff8881da2418c0 RBX: 000000000000752f RCX: ffffffff81302ad0 RDX: 0000000000000002 RSI: ffffffff81302add RDI: 0000000000000005 RBP: 0000000000000020 R08: ffff8881da2418c0 R09: ffffed103b666aec R10: ffff8881db33575b R11: ffffed103b666aeb R12: 0000000000000002 R13: 0000000000000003 R14: dffffc0000000000 R15: ffffffff87009100 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5a98858000 CR3: 00000001c3268000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: _usecs_to_jiffies include/linux/jiffies.h:377 [inline] __usecs_to_jiffies+0x50/0x60 kernel/time/time.c:567 usecs_to_jiffies include/linux/jiffies.h:416 [inline] net_rx_action+0x91/0xef0 net/core/dev.c:6621 __trace_hardirqs_on_caller kernel/locking/lockdep.c:3657 [inline] lockdep_hardirqs_on+0x3c7/0x5d0 kernel/locking/lockdep.c:3702 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x1f/0x30 kernel/locking/spinlock.c:199 finish_lock_switch kernel/sched/core.c:3106 [inline] finish_task_switch+0x11d/0x5d0 kernel/sched/core.c:3206 __write_once_size include/linux/compiler.h:225 [inline] finish_task kernel/sched/core.c:3077 [inline] finish_task_switch+0xef/0x5d0 kernel/sched/core.c:3205 napi_busy_loop+0x9e0/0x9e0 net/core/dev.c:6383 lock_is_held include/linux/lockdep.h:406 [inline] rcu_read_lock_sched_held+0x9c/0xd0 kernel/rcu/update.c:121 rcu_read_lock_bh_held+0xb0/0xb0 kernel/rcu/update.c:333 __do_softirq+0x21e/0x9aa kernel/softirq.c:292 takeover_tasklets+0x770/0x770 kernel/softirq.c:75 run_ksoftirqd kernel/softirq.c:604 [inline] run_ksoftirqd+0x1f/0x40 kernel/softirq.c:596 smpboot_thread_fn+0x3e8/0x870 kernel/smpboot.c:165 __smpboot_create_thread.part.0+0x340/0x340 kernel/smpboot.c:208 __kthread_parkme+0x118/0x1d0 kernel/kthread.c:212 __smpboot_create_thread.part.0+0x340/0x340 kernel/smpboot.c:208 kthread+0x326/0x430 kernel/kthread.c:268 kthread_create_on_node+0xf0/0xf0 kernel/kthread.c:405 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351