INFO: task syz-executor.5:2109 blocked for more than 140 seconds. Not tainted 4.9.170+ #48 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D24648 2109 1 0x00000004 ffff8801cec62f80 ffff8801a8358580 ffff8801db621000 ffff8801964097c0 ffff8801db621018 ffff8801b2097b28 ffffffff82801a4e ffff8801cec62f80 ffff8801b2097aa0 00ffffff81bb61ac ffff8801db6218f0 1ffff10036412f54 Call Trace: [<000000007efca2e7>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000f5003b9c>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000eb137d69>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000eb137d69>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000d312ab4b>] __lo_release drivers/block/loop.c:1642 [inline] [<00000000d312ab4b>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 [<000000003404bf49>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606 [<0000000003eca1fc>] blkdev_put+0x88/0x560 fs/block_dev.c:1671 [<00000000a8278a73>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678 [<00000000c9bc35a4>] __fput+0x274/0x720 fs/file_table.c:208 [<00000000a133b553>] ____fput+0x16/0x20 fs/file_table.c:244 [<000000002dd16d67>] task_work_run+0x108/0x180 kernel/task_work.c:116 [<000000000a9097e3>] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [<000000000a9097e3>] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:162 [<0000000077a71faf>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] [<0000000077a71faf>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline] [<0000000077a71faf>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290 [<00000000e5dbc3e6>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/24: #0: (rcu_read_lock){......}, at: [<0000000048bad86f>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<0000000048bad86f>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<00000000912e5eaa>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 2 locks held by getty/2022: #0: (&tty->ldisc_sem){++++++}, at: [<00000000dd6860ce>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<000000009a240b13>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.5/2109: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000043112a7d>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<000000003e64e4a9>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<00000000d312ab4b>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<00000000d312ab4b>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by syz-executor.1/2129: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ae1fa6f6>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000033711c5e>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.4/2136: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ae1fa6f6>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000033711c5e>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.2/20782: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<0000000005c6ec5a>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<000000007a9f11e5>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by blkid/20780: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ae1fa6f6>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000033711c5e>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 1 lock held by blkid/20785: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ae1fa6f6>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.170+ #48 ffff8801d98d7cc8 ffffffff81b4fb21 0000000000000000 0000000000000000 0000000000000000 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5adbc 0000000000000000 0000000000000000 0000000000000000 Call Trace: [<00000000a7c62521>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000a7c62521>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000f1fe6ac1>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000e29e4016>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<0000000075933a9a>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<0000000058ce0214>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<0000000058ce0214>] check_hung_task kernel/hung_task.c:126 [inline] [<0000000058ce0214>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<0000000058ce0214>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<00000000197e6964>] kthread+0x278/0x310 kernel/kthread.c:211 [<0000000021d3805d>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.9.170+ #48 task: 0000000038580eef task.stack: 0000000059494327 RIP: 0010:[] c [<00000000f8f516d0>] __lock_acquire+0x8b8/0x4350 kernel/locking/lockdep.c:3371 RSP: 0018:ffff8801db707d30 EFLAGS: 00000083 RAX: 0000000000000001 RBX: ffffffff836201a0 RCX: 1ffff1003b4d670a RDX: 1ffff1003b4d6705 RSI: ffff8801da6b3830 RDI: ffffffff836201b8 RBP: ffff8801db707eb8 R08: 0000000000000001 R09: 00000000000049f1 R10: ffff8801da6b3830 R11: 0000000000000001 R12: dffffc0000000000 R13: ffff8801da6b3830 R14: f6345063bd17a015 R15: ffff8801da6b2f80 FS: 0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000017b6000 CR3: 00000001d7337000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Stack: ffffffff81bb61acc ffff8801db707d78c ffffffff81bb61acc ffff8801d3c6a068c ffff8801d3c6a070c 0000000000000246c ffffffff811d1d33c 0000000000000001c 0000000100000000c ffff8801d3c697c0c 0000000000000001c ffffffff83c742d0c Call Trace: [<000000008cdb8026>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 [<000000000dd028b3>] seqcount_lockdep_reader_access include/linux/seqlock.h:80 [inline] [<000000000dd028b3>] read_seqcount_begin include/linux/seqlock.h:163 [inline] [<000000000dd028b3>] ktime_get kernel/time/timekeeping.c:760 [inline] [<000000000dd028b3>] ktime_get+0x6f/0x1c0 kernel/time/timekeeping.c:750 [<0000000042a1fcdf>] tick_nohz_irq_enter kernel/time/tick-sched.c:1144 [inline] [<0000000042a1fcdf>] tick_irq_enter+0xcc/0x220 kernel/time/tick-sched.c:1165 [<000000002fd39197>] irq_enter+0xb3/0xd0 kernel/softirq.c:349 [<000000007880349a>] smp_reschedule_interrupt+0xa/0x90 arch/x86/kernel/smp.c:267 [<00000000b9fad522>] reschedule_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:671 d [<000000000b25d0e5>] ? native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:56 [<00000000f51957e0>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428 [<000000000e479ee3>] default_idle_call+0x36/0x60 kernel/sched/idle.c:97 [<000000002cc4b92a>] cpuidle_idle_call kernel/sched/idle.c:155 [inline] [<000000002cc4b92a>] cpu_idle_loop kernel/sched/idle.c:248 [inline] [<000000002cc4b92a>] cpu_startup_entry+0x283/0x3a0 kernel/sched/idle.c:303 [<0000000091f9b5d8>] start_secondary+0x31c/0x410 arch/x86/kernel/smpboot.c:251 Code: cc0 c74 c08 c3c c03 c0f c8e c62 c28 c00 c00 c41 c8b c87 ca8 c08 c00 c00 c83 cc0 c01 c83 cf8 c2f c41 c89 c87 ca8 c08 c00 c00 c0f c87 ca2 c17 c00 c00 c3b c05 ca8 cef c61 c02 c<41> cbb c01 c00 c00 c00 c0f c86 c99 c00 c00 c00 c89 c05 c96 cef c61 c02 ce9 c8e c00 c