INFO: task systemd-shutdow:1 blocked for more than 143 seconds. Not tainted 5.8.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-shutdow D24208 1 0 0x00004000 Call Trace: context_switch kernel/sched/core.c:3430 [inline] __schedule+0x8a1/0x1db0 kernel/sched/core.c:4155 schedule+0xcd/0x2b0 kernel/sched/core.c:4230 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:665 device_shutdown+0x18/0x5b5 drivers/base/core.c:3748 kernel_restart+0x11/0x30 kernel/reboot.c:246 __do_sys_reboot+0x31e/0x3e0 kernel/reboot.c:347 do_syscall_64+0x50/0x90 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f8a3860c8c6 Code: Bad RIP value. RSP: 002b:00007ffd4d47d4e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8a3860c8c6 RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead RBP: 00007ffd4d47d578 R08: 0000000000000028 R09: 0000000000000005 R10: 0000000000000002 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000556dff312150 R15: 00007ffd4d47d868 Showing all locks held in the system: 1 lock held by systemd-shutdow/1: #0: ffffffff870e6528 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a3/0x3e0 kernel/reboot.c:344 1 lock held by khungtaskd/23: #0: ffffffff8710fa20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5779 5 locks held by kworker/1:4/3126: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 5.8.0-rc1-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+0xf6/0x16e lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x190/0x1aa lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xcfe/0xff0 kernel/hung_task.c:295 kthread+0x352/0x460 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.8.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:write_comp_data+0x2e/0x80 kernel/kcov.c:218 Code: 25 40 ef 01 00 65 8b 05 70 7f c2 7e a9 00 01 ff 00 74 10 f6 c4 01 74 5c 41 8b 80 34 13 00 00 85 c0 74 51 41 8b 80 10 13 00 00 <83> f8 03 75 45 49 8b 80 18 13 00 00 45 8b 80 14 13 00 00 4c 8b 08 RSP: 0018:ffffffff87007af8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff813110a2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000006 R08: ffffffff8702f840 R09: fffffbfff12e284d R10: ffffffff89714267 R11: fffffbfff12e284c R12: ffff8881db226e2c R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd4d47cb98 CR3: 00000001d321e000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ktime_get+0x22/0x1c0 kernel/time/timekeeping.c:754 tick_nohz_irq_enter kernel/time/tick-sched.c:1274 [inline] tick_irq_enter+0x78/0x250 kernel/time/tick-sched.c:1295 irq_enter_rcu+0xf3/0x120 kernel/softirq.c:353 sysvec_call_function_single+0x13/0x1b0 arch/x86/kernel/smp.c:243 asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:604 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:49 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline] RIP: 0010:acpi_safe_halt+0x72/0x90 drivers/acpi/processor_idle.c:108 Code: 74 06 5b e9 d0 05 a6 fb e8 cb 05 a6 fb e8 d6 69 ab fb e9 0c 00 00 00 e8 bc 05 a6 fb 0f 00 2d 75 58 6b 00 e8 b0 05 a6 fb fb f4 e8 c8 67 ab fb 5b e9 a2 05 a6 fb 48 89 df e8 8a b4 cf fb eb ab RSP: 0018:ffffffff87007c58 EFLAGS: 00000293 RAX: ffffffff8702f840 RBX: 0000000000000000 RCX: 1ffffffff0fd4d32 RDX: 0000000000000000 RSI: ffffffff85996970 RDI: ffffffff87030078 RBP: ffff8881d8cba064 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881d8cba064 R13: 1ffffffff0e00f95 R14: ffff8881d8cba065 R15: 0000000000000001 acpi_idle_do_entry+0xa9/0xe0 drivers/acpi/processor_idle.c:525 acpi_idle_enter+0x42b/0xac0 drivers/acpi/processor_idle.c:651 cpuidle_enter_state+0xdb/0xc20 drivers/cpuidle/cpuidle.c:234 cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:345 call_cpuidle kernel/sched/idle.c:117 [inline] cpuidle_idle_call kernel/sched/idle.c:207 [inline] do_idle+0x3c2/0x500 kernel/sched/idle.c:269 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:365 start_kernel+0x9fc/0xa39 init/main.c:1043 secondary_startup_64+0xb6/0xc0 arch/x86/kernel/head_64.S:243