INFO: task syz-executor.0:2098 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 ffff8801c7d37648 25088 2098 1 0x00000004 ffff8801c7d37648 ffff8801d4ca0000 195725e67eebee1b ffff8801d4ca0000 0000000000000001 ffff8801d4ca0800 ffff8801db71f180 ffff8801db71f1a8 ffff8801db71e898 ffff8801d24c2f80 ffff8801d4ca0000 ffffed0038fa6001 Call Trace: [] schedule+0x99/0x1d0 kernel/sched/core.c:3355 [] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3388 [] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [] mutex_lock_nested+0x3c2/0xb80 kernel/locking/mutex.c:621 [] lo_open+0x1d/0xb0 drivers/block/loop.c:1633 [] __blkdev_get+0x8b1/0xdf0 fs/block_dev.c:1278 [] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353 [] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_sys_open+0x2f8/0x600 fs/open.c:1038 [] SYSC_open fs/open.c:1056 [inline] [] SyS_open+0x2d/0x40 fs/open.c:1051 [] entry_SYSCALL_64_fastpath+0x1e/0x9a 2 locks held by syz-executor.0/2098: #0: (&bdev->bd_mutex){+.+.+.}, at: [] __blkdev_get+0x10c/0xdf0 fs/block_dev.c:1199 #1: (loop_index_mutex){+.+.+.}, at: [] lo_open+0x1d/0xb0 drivers/block/loop.c:1633 Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #4 task: ffff8801da6f4740 task.stack: ffff8800001d0000 RIP: 0010:[] [] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline] RIP: 0010:[] [] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69 RSP: 0018:ffff8800001d7c88 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300 RBP: ffff8800001d7cb8 R08: 0000000000000018 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001ce1000 CR3: 00000001cf2fb000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34 000000000001b6c0 0000000000000008 ffff8800001d7cd8 ffffffff81092bee 0000000000000008 ffffffff82924260 ffff8800001d7d30 ffffffff81ab8252 Call Trace: [] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae 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.cold+0xd3/0xee kernel/hung_task.c:238 [] kthread+0x273/0x310 kernel/kthread.c:211 [] 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 NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.174+ #4 task: ffff8801da6897c0 task.stack: ffff8801da698000 RIP: 0010:[] [] mark_lock+0xb1/0x1440 kernel/locking/lockdep.c:2907 RSP: 0018:ffff8801da69f988 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff83a8a8b0 RCX: 1ffff1003b4d1415 RDX: 1ffffffff075151c RSI: ffff8801da68a088 RDI: ffffffff83a8a8e0 RBP: ffff8801da69f9d0 R08: 0000000000000000 R09: ffff8801da68a0a8 R10: ffffffff82836880 R11: 0000000000000000 R12: ffff8801da68a088 R13: ffff8801da6897c0 R14: 0000000000001000 R15: 000000000000000c FS: 0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001384000 CR3: 00000000b641b000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: 0000000000000046 ffff8801da68a0a0 1ffffffff0506d10 ffff8801da69f9b0 0000000000000085 ffff8801da6897c0 ffff8801da68a088 0000000000000000 0000000000000000 ffff8801da69fb60 ffffffff811fffff 0000000000000000 Call Trace: [] __lock_acquire+0xa4f/0x4f50 kernel/locking/lockdep.c:3173 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:112 [inline] [] _raw_spin_lock_irqsave+0x50/0x70 kernel/locking/spinlock.c:159 [] lock_hrtimer_base.isra.0+0x75/0x130 kernel/time/hrtimer.c:152 [] hrtimer_start_range_ns+0xc6/0x1450 kernel/time/hrtimer.c:996 [] hrtimer_start_expires include/linux/hrtimer.h:407 [inline] [] tick_nohz_restart+0x182/0x200 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+0x73a/0x810 kernel/sched/idle.c:301 [] start_secondary+0x31d/0x410 arch/x86/kernel/smpboot.c:245 Code: eb b0 01 00 00 48 81 c3 40 c8 a7 83 48 8d 7b 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 a5 0e 00 00 <4c> 85 73 30 0f 84 cb 00 00 00 41 be 01 00 00 00 48 83 c4 20 44