INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=1144, c=1143, q=65) All QSes seen, last rcu_preempt kthread activity 10502 (4294994573-4294984071), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor271 R running task 27976 8228 7974 0x00000000 Call Trace: sched_show_task.cold+0x333/0x39a kernel/sched/core.c:5168 print_other_cpu_stall kernel/rcu/tree.c:1501 [inline] check_cpu_stall kernel/rcu/tree.c:1616 [inline] __rcu_pending kernel/rcu/tree.c:3390 [inline] rcu_pending kernel/rcu/tree.c:3452 [inline] rcu_check_callbacks.cold+0xd29/0xd8d kernel/rcu/tree.c:2792 update_process_times+0x29/0x60 kernel/time/timer.c:1591 tick_sched_handle+0x7d/0x150 kernel/time/tick-sched.c:165 tick_sched_timer+0x92/0x200 kernel/time/tick-sched.c:1223 __run_hrtimer kernel/time/hrtimer.c:1223 [inline] __hrtimer_run_queues+0x30b/0xc80 kernel/time/hrtimer.c:1287 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1079 [inline] smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1104 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793 RIP: 0010:__mutex_unlock_slowpath+0x261/0x770 kernel/locking/mutex.c:1013 RSP: 0018:ffff8880aaa57928 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10 RAX: ffff88809df1c240 RBX: 0000000000000000 RCX: fffffbfff17d93a8 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000286 RBP: ffffffff89472920 R08: ffff88809df1c240 R09: dffffc0000000000 R10: 0000000000000000 R11: ffff88809df1c240 R12: ffffffff8bec9d40 R13: 1ffff1101554af29 R14: ffff8880aaa57968 R15: 0000000000000003 tty_open_by_driver drivers/tty/tty_io.c:1958 [inline] tty_open+0x3d5/0x8b0 drivers/tty/tty_io.c:2021 chrdev_open+0x23c/0x6d0 fs/char_dev.c:423 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f0578eadaf9 RSP: 002b:00007f0578e5f318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f0578f353e8 RCX: 00007f0578eadaf9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f0578f353e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f R13: 00007fffc41d99af R14: 00007f0578e5f400 R15: 0000000000022000 rcu_preempt kthread starved for 10502 jiffies! g1144 c1143 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0 rcu_preempt R running task 30008 8 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x4af/0xe90 kernel/time/timer.c:1747 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 INFO: rcu_sched detected stalls on CPUs/tasks: (detected by 0, t=10539 jiffies, g=297, c=296, q=5) All QSes seen, last rcu_sched kthread activity 10539 (4294994611-4294984072), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor271 R running task 27976 8228 7974 0x00000000 Call Trace: sched_show_task.cold+0x333/0x39a kernel/sched/core.c:5168 print_other_cpu_stall kernel/rcu/tree.c:1501 [inline] check_cpu_stall kernel/rcu/tree.c:1616 [inline] __rcu_pending kernel/rcu/tree.c:3390 [inline] rcu_pending kernel/rcu/tree.c:3452 [inline] rcu_check_callbacks.cold+0xd29/0xd8d kernel/rcu/tree.c:2792 update_process_times+0x29/0x60 kernel/time/timer.c:1591 tick_sched_handle+0x7d/0x150 kernel/time/tick-sched.c:165 tick_sched_timer+0x92/0x200 kernel/time/tick-sched.c:1223 __run_hrtimer kernel/time/hrtimer.c:1223 [inline] __hrtimer_run_queues+0x30b/0xc80 kernel/time/hrtimer.c:1287 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1079 [inline] smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1104 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793 RIP: 0010:__mutex_unlock_slowpath+0x261/0x770 kernel/locking/mutex.c:1013 RSP: 0018:ffff8880aaa57928 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10 RAX: ffff88809df1c240 RBX: 0000000000000000 RCX: fffffbfff17d93a8 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000286 RBP: ffffffff89472920 R08: ffff88809df1c240 R09: dffffc0000000000 R10: 0000000000000000 R11: ffff88809df1c240 R12: ffffffff8bec9d40 R13: 1ffff1101554af29 R14: ffff8880aaa57968 R15: 0000000000000003 tty_open_by_driver drivers/tty/tty_io.c:1958 [inline] tty_open+0x3d5/0x8b0 drivers/tty/tty_io.c:2021 chrdev_open+0x23c/0x6d0 fs/char_dev.c:423 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f0578eadaf9 RSP: 002b:00007f0578e5f318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f0578f353e8 RCX: 00007f0578eadaf9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f0578f353e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f R13: 00007fffc41d99af R14: 00007f0578e5f400 R15: 0000000000022000 rcu_sched kthread starved for 10539 jiffies! g297 c296 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 rcu_sched R running task 30008 9 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x4af/0xe90 kernel/time/timer.c:1747 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404