INFO: task syz-executor.0:2131 blocked for more than 140 seconds.
Not tainted 4.4.174+ #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0 D ffff8800a76279d8 25088 2131 1 0x00000004
ffff8800a76279d8 ffff8800b8f0df00 9f0700bb79963d43 ffff8800b8f0df00
0000000000000001 ffff8800b8f0e700 ffff8801db61f180 ffff8801db61f1a8
ffff8801db61e898 ffff8801d6830000 ffff8800b8f0df00 ffffed0014ec4001
Call Trace:
[<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
[<ffffffff8270a333>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3388
[<ffffffff8270c492>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
[<ffffffff8270c492>] mutex_lock_nested+0x3c2/0xb80 kernel/locking/mutex.c:621
[<ffffffff81a7920f>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
[<ffffffff81d3ed4c>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:649
[<ffffffff81d42101>] loop_clr_fd+0x7f1/0xa70 drivers/block/loop.c:1093
[<ffffffff81d46ca6>] lo_ioctl+0x7b6/0x1a70 drivers/block/loop.c:1426
[<ffffffff81a7ae89>] __blkdev_driver_ioctl block/ioctl.c:288 [inline]
[<ffffffff81a7ae89>] blkdev_ioctl+0xed9/0x1940 block/ioctl.c:584
[<ffffffff8155036e>] block_ioctl+0xde/0x120 fs/block_dev.c:1625
[<ffffffff814d23f7>] vfs_ioctl fs/ioctl.c:43 [inline]
[<ffffffff814d23f7>] file_ioctl fs/ioctl.c:470 [inline]
[<ffffffff814d23f7>] do_vfs_ioctl+0x6e7/0xfa0 fs/ioctl.c:605
[<ffffffff814d2d3f>] SYSC_ioctl fs/ioctl.c:622 [inline]
[<ffffffff814d2d3f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
[<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
2 locks held by syz-executor.0/2131:
#0: (loop_ctl_mutex/1){+.+.+.}, at: [<ffffffff81d46575>] lo_ioctl+0x85/0x1a70 drivers/block/loop.c:1416
#1: (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81a7920f>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.174+ #4
task: ffffffff82e151c0 task.stack: ffffffff82e00000
RIP: 0010:[<ffffffff810a1dc2>] [<ffffffff810a1dc2>] native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:53
RSP: 0018:ffffffff82e07db0 EFLAGS: 00000246
RAX: 0000000000000007 RBX: ffffffff8319bf68 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff82e15a84
RBP: ffffffff82e07de0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff82e08000 R14: dffffc0000000000 R15: ffffffff82e00000
FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6e060b2000 CR3: 00000000b90f5000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Stack:
ffffffff81020b16 ffffffff82e00000 0000000000000000 ffffffff82e08000
dffffc0000000000 ffffffff82e00000 ffffffff82e07df0 ffffffff81022d50
ffffffff82e07e08 ffffffff811eb4c8 0000000000000000 ffffffff82e07ed0
Call Trace:
[<ffffffff81022d50>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:423
[<ffffffff811eb4c8>] default_idle_call+0x48/0x70 kernel/sched/idle.c:93
[<ffffffff811ebca1>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
[<ffffffff811ebca1>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
[<ffffffff811ebca1>] cpu_startup_entry+0x6d1/0x810 kernel/sched/idle.c:301
[<ffffffff827055f9>] rest_init+0x190/0x199 init/main.c:410
[<ffffffff831d58a0>] start_kernel+0x64a/0x67e init/main.c:682
[<ffffffff831d430a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
[<ffffffff831d4443>] x86_64_start_kernel+0x137/0x15a arch/x86/kernel/head64.c:185
Code: 2e 0f 1f 84 00 00 00 00 00 fa c3 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 fb c3 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 fb f4 <c3> 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 0f 1f 40 00 66
NMI backtrace for cpu 1
CPU: 1 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #4
task: ffff8801da6f2f80 task.stack: ffff8801d9ed8000
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801d9edfc88 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8801d9edfcb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe5b74d1000 CR3: 00000000b90f5000 CR4: 00000000001606b0
Stack:
0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
000000000001b6c0 0000000000000008 ffff8801d9edfcd8 ffffffff81092bee
0000000000000008 ffffffff82924260 ffff8801d9edfd30 ffffffff81ab8252
Call Trace:
[<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33
[<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae lib/nmi_backtrace.c:85
[<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
[<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
[<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff813b4762>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
[<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
[<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
[<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1