INFO: task syz-executor1:8833 blocked for more than 120 seconds. Not tainted 4.4.107-g610c835 #12 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D ffff8801d5f1fa28 28792 8833 3531 0x00000004 ffff8801d5f1fa28 ffff8801d5f1f9d8 0000000000000246 0000000000000296 0000000041b58ab3 ffffffff83fa7300 ffff8801db21f878 ffff8801db21f8a0 ffff8801db21ef98 ffff8800b7ed97c0 ffff8800b7ac5f00 ffff8801d5f18000 Call Trace: [] schedule+0x9a/0x1c0 kernel/sched/core.c:3351 [] blk_mq_freeze_queue_wait+0x120/0x240 block/blk-mq.c:95 [] blk_freeze_queue block/blk-mq.c:112 [inline] [] blk_mq_freeze_queue+0x1d/0x20 block/blk-mq.c:121 [] __loop_update_dio+0x47b/0x5d0 drivers/block/loop.c:214 [] loop_set_dio drivers/block/loop.c:1334 [inline] [] lo_ioctl+0x13c0/0x19c0 drivers/block/loop.c:1388 [] __blkdev_driver_ioctl block/ioctl.c:288 [inline] [] blkdev_ioctl+0x4ab/0x1990 block/ioctl.c:584 [] block_ioctl+0xde/0x120 fs/block_dev.c:1625 [] vfs_ioctl fs/ioctl.c:43 [inline] [] do_vfs_ioctl+0x7aa/0xee0 fs/ioctl.c:607 [] SYSC_ioctl fs/ioctl.c:622 [inline] [] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613 [] entry_SYSCALL_64_fastpath+0x16/0x76 1 lock held by syz-executor1/8833: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [] lo_ioctl+0x8f/0x19c0 drivers/block/loop.c:1348 Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.107-g610c835 #12 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffffffff84214840 task.stack: ffffffff84200000 RIP: 0010:[] [] __lock_release kernel/locking/lockdep.c:3451 [inline] RIP: 0010:[] [] lock_release+0x5f3/0xc10 kernel/locking/lockdep.c:3611 RSP: 0018:ffffffff84207b20 EFLAGS: 00000806 RAX: dffffc0000000000 RBX: 000000000000003c RCX: 0000000000000000 RDX: 1ffffffff0ade6c0 RSI: ffffffff8583a620 RDI: ffffffff842150a0 RBP: ffffffff84207bd0 R08: 1ffff1003b4113bc R09: 0000000000000001 R10: 0000000000000000 R11: 1ffffffff0840f46 R12: ffffffff8583a620 R13: 0000000000000001 R14: ffffffff842150d8 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbd966c2000 CR3: 00000001d1910000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff84207bc8 0000000000000046 0000000000000000 ffffffff81d65e92 ffffffff00000000 ffffffff842150a8 0000000184207d20 0000000000000046 Call Trace: [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] [] _raw_spin_unlock_irqrestore+0x1f/0x70 kernel/locking/spinlock.c:191 [] debug_object_deactivate+0x26d/0x3c0 lib/debugobjects.c:491 [] debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline] [] debug_deactivate kernel/time/hrtimer.c:461 [inline] [] remove_hrtimer kernel/time/hrtimer.c:949 [inline] [] hrtimer_try_to_cancel+0x189/0x660 kernel/time/hrtimer.c:1057 [] hrtimer_cancel+0x22/0x40 kernel/time/hrtimer.c:1077 [] tick_nohz_restart+0x1e/0x190 kernel/time/tick-sched.c:559 [] tick_nohz_restart_sched_tick kernel/time/tick-sched.c:711 [inline] [] tick_nohz_idle_exit+0x247/0x3d0 kernel/time/tick-sched.c:931 [] cpu_idle_loop kernel/sched/idle.c:267 [inline] [] cpu_startup_entry+0x2e7/0x820 kernel/sched/idle.c:301 [] rest_init+0x189/0x190 init/main.c:409 [] start_kernel+0x6b4/0x6e9 init/main.c:680 [] 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: 85 c0 0f 84 84 00 00 00 41 83 c7 01 44 39 7d d0 0f 87 15 fe ff ff 48 c7 c2 00 36 6f 85 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 48 c7 c0 00 36 6f 85 83 e0 07 83 c0 03 38 d0 7c 08 NMI backtrace for cpu 1 CPU: 1 PID: 485 Comm: khungtaskd Not tainted 4.4.107-g610c835 #12 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d9044740 task.stack: ffff8800bac68000 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:ffff8800bac6fcb8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300 RBP: ffff8800bac6fce0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000003 R14: ffffffff8426abe0 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000018baec0 CR3: 00000001d5773000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8426abe0 ffffffff847e8600 00000000000194a0 0000000000000040 dffffc0000000000 ffff8800bac6fd00 ffffffff810b8e1b ffffffff839f53e0 0000000000000003 ffff8800bac6fd60 ffffffff81d0f4d7 ffffffff81417c73 Call Trace: [] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace+0x4a7/0x550 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+0x3f/0x70 arch/x86/entry/entry_64.S:468 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 3b 09 17 00 4c 89 e7 57 9d 0f 1f