INFO: task syz-executor2:6125 blocked for more than 120 seconds. Not tainted 4.4.115-g55a366596 #14 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D ffff8801c51c78c8 29240 6125 3852 0x00000002 ffff8801c51c78c8 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffff8801c51c7800 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8 ffff8801d8e44800 ffff8800ab101800 0000000000000000 Call Trace: [] schedule+0x7a/0x1b0 kernel/sched/core.c:3353 [] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3386 [] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [] mutex_lock_nested+0x306/0x850 kernel/locking/mutex.c:621 [] odev_release+0x4a/0x70 sound/core/seq/oss/seq_oss.c:151 [] __fput+0x233/0x6d0 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x104/0x180 kernel/task_work.c:115 [] exit_task_work include/linux/task_work.h:21 [inline] [] do_exit+0x82a/0x2a10 kernel/exit.c:755 [] do_group_exit+0x108/0x320 kernel/exit.c:885 [] get_signal+0x4f2/0x1550 kernel/signal.c:2317 [] do_signal+0x8b/0x1d40 arch/x86/kernel/signal.c:712 [] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:247 [] prepare_exit_to_usermode arch/x86/entry/common.c:282 [inline] [] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:347 [] int_ret_from_sys_call+0x25/0xa3 INFO: lockdep is turned off. Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.115-g55a366596 #14 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffffffff84217840 task.stack: ffffffff84200000 RIP: 0010:[] [] native_apic_mem_write+0xc/0x10 arch/x86/include/asm/apic.h:94 RSP: 0018:ffffffff84207c38 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff8426f3a0 RCX: 0000000000000020 RDX: 1ffffffff084de91 RSI: 00000000000634f8 RDI: 0000000000000380 RBP: ffffffff84207c38 R08: ffff88021fffd018 R09: 0000000000000006 R10: ffffed0043fffa01 R11: 0000000000000000 R12: 00000000000634f8 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f38c475f000 CR3: 00000001c6ee4000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff84207c58 ffffffff810b084a 0000000000000000 ffff8801db217fc0 ffffffff84207c98 ffffffff812cfe0a 0000003823df3800 ffff8801db217fc0 0000000000000001 0000003823df3800 ffff8801db2196b8 0000000000000000 Call Trace: [] apic_write arch/x86/include/asm/apic.h:392 [inline] [] lapic_next_event+0x5a/0x90 arch/x86/kernel/apic/apic.c:458 [] clockevents_program_event+0x28a/0x350 kernel/time/clockevents.c:339 [] tick_program_event+0xa8/0x110 kernel/time/tick-oneshot.c:47 [] hrtimer_reprogram kernel/time/hrtimer.c:663 [inline] [] hrtimer_start_range_ns+0x1040/0x1450 kernel/time/hrtimer.c:1024 [] hrtimer_start_expires include/linux/hrtimer.h:407 [inline] [] tick_nohz_restart+0x137/0x190 kernel/time/tick-sched.c:566 [] tick_nohz_restart_sched_tick kernel/time/tick-sched.c:726 [inline] [] tick_nohz_idle_exit+0x247/0x3d0 kernel/time/tick-sched.c:946 [] cpu_idle_loop kernel/sched/idle.c:267 [inline] [] cpu_startup_entry+0x2a5/0x8f0 kernel/sched/idle.c:301 [] rest_init+0x189/0x190 init/main.c:410 [] start_kernel+0x6b9/0x6ee init/main.c:682 [] x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:196 [] x86_64_start_kernel+0x140/0x163 arch/x86/kernel/head64.c:185 Code: a0 06 00 66 90 66 2e 0f 1f 84 00 00 00 00 00 55 be 01 00 00 00 48 89 e5 e8 f2 d1 1b 00 5d c3 55 89 ff 48 89 e5 89 b7 00 b0 5f ff <5d> c3 66 90 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 53 89 fb NMI backtrace for cpu 1 CPU: 1 PID: 485 Comm: khungtaskd Not tainted 4.4.115-g55a366596 #14 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d9336000 task.stack: ffff8800bad10000 RIP: 0010:[] [] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline] RIP: 0010:[] [] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline] RIP: 0010:[] [] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline] RIP: 0010:[] [] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69 RSP: 0018:ffff8800bad17cb8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: ffffffff8126a2f2 RDX: 0000000000000c00 RSI: 0000000000000002 RDI: ffffffffff5fb300 RBP: ffff8800bad17ce0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: fffffbfff0ad7e2c R12: 0000000000000246 R13: 0000000000000003 R14: ffffffff8426f3a0 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c421609010 CR3: 00000001c6ee4000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8426f3a0 ffffffff847ef7c0 fffffbfff08fd9ac dffffc0000000000 ffff8801db31bca0 ffff8800bad17d00 ffffffff810b99eb ffffffff839f6200 0000000000000003 ffff8800bad17d60 ffffffff81d0ecf4 0000000000000001 Call Trace: [] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85 [] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 [] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6fa/0xae0 kernel/hung_task.c:238 [] kthread+0x268/0x300 kernel/kthread.c:211 [] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:506 Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 7b 2f 17 00 4c 89 e7 57 9d 0f 1f