INFO: task syz-executor.3:18440 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D26256 18440   7037 0x80000002
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_release+0x20/0x1b0 drivers/block/loop.c:1666
 __blkdev_put+0x434/0x7f0 fs/block_dev.c:1791
 blkdev_put+0x88/0x510 fs/block_dev.c:1856
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x7df/0x2c10 kernel/exit.c:874
 do_group_exit+0x111/0x330 kernel/exit.c:977
 get_signal+0x381/0x1cd0 kernel/signal.c:2409
 do_signal+0x86/0x19a0 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x15c/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459279
RSP: 002b:00007efc4b7bccf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000075bfc8 RCX: 0000000000459279
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bfc8
RBP: 000000000075bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bfcc
R13: 00007fff4e23205f R14: 00007efc4b7bd9c0 R15: 000000000075bfcc
INFO: task syz-executor.2:1739 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28392  1739   7036 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_open+0x1d/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x2c7/0x1120 fs/block_dev.c:1472
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:758
 vfs_open+0x105/0x220 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x413161
RSP: 002b:00007f26c6dbd9f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f26c6dbe6d4 RCX: 0000000000413161
RDX: 00007f26c6dbdbaa RSI: 0000000000000002 RDI: 00007f26c6dbdba0
RBP: 0000000000001000 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000005
R13: 0000000000000005 R14: 00007f26c6dbe6d4 R15: 00000000ffffffff
INFO: task syz-executor.5:1744 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D25520  1744   7033 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_release+0x20/0x1b0 drivers/block/loop.c:1666
 __blkdev_put+0x434/0x7f0 fs/block_dev.c:1791
 blkdev_put+0x88/0x510 fs/block_dev.c:1856
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x412f61
RSP: 002b:00007f65707679f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f65707686d4 RCX: 0000000000412f61
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000006
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000000c
R10: 0000000000000064 R11: 0000000000000293 R12: 0000000000000005
R13: 0000000000000000 R14: 0000000000000006 R15: 0000000000000001
INFO: task syz-executor.3:1746 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D29120  1746   7037 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 loop_control_ioctl+0x153/0x2f0 drivers/block/loop.c:1996
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459279
RSP: 002b:00007efc4b7ddc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459279
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007efc4b7de6d4
R13: 00000000004c2936 R14: 00000000004d59a0 R15: 00000000ffffffff
INFO: task syz-executor.0:1751 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D27728  1751  30578 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:614
 loop_set_status+0xc25/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa6/0xf0 drivers/block/loop.c:1301
 lo_ioctl+0x5c1/0x1ce0 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x96b/0x1860 block/ioctl.c:594
 block_ioctl+0xde/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4590e7
RSP: 002b:00007fa7876749f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa7876756d4 RCX: 00000000004590e7
RDX: 00007fa787674ab0 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000004
R13: 0000000000000004 R14: 0000000000000005 R15: 00000000ffffffff
INFO: task blkid:1748 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28512  1748  31160 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 blkdev_put+0x2b/0x510 fs/block_dev.c:1814
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f604efc82b0
RSP: 002b:00007ffd0522c668 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f604efc82b0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000028 R09: 0000000001680000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000007ee030
R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005
INFO: task blkid:1750 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D29040  1750  30672 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_open+0x1d/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0xaad/0x1120 fs/block_dev.c:1537
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:758
 vfs_open+0x105/0x220 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f5c0db74120
RSP: 002b:00007ffe0c11ee78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5c0db74120
RDX: 00007ffe0c11ff40 RSI: 0000000000000000 RDI: 00007ffe0c11ff40
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000b4a030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task syz-executor.1:1762 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D28424  1762  31125 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:758
 vfs_open+0x105/0x220 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x413161
RSP: 002b:00007ff89a9259f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ff89a9266d4 RCX: 0000000000413161
RDX: 00007ff89a925baa RSI: 0000000000000002 RDI: 00007ff89a925ba0
RBP: 0000000000001000 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000005
R13: 0000000000000005 R14: 00007ff89a9266d4 R15: 00000000ffffffff
INFO: task syz-executor.4:1760 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28392  1760   7030 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_open+0x1d/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x2c7/0x1120 fs/block_dev.c:1472
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:758
 vfs_open+0x105/0x220 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x413161
RSP: 002b:00007f01187d89f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f01187d96d4 RCX: 0000000000413161
RDX: 00007f01187d8baa RSI: 0000000000000002 RDI: 00007f01187d8ba0
RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000004
R13: 0000000000000004 R14: 00000000004defb8 R15: 00000000ffffffff
INFO: task blkid:1761 blocked for more than 140 seconds.
      Not tainted 4.14.125 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28928  1761  30947 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_open+0x1d/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x2c7/0x1120 fs/block_dev.c:1472
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:758
 vfs_open+0x105/0x220 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f7f03c5b120
RSP: 002b:00007ffd41cbbed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7f03c5b120
RDX: 00007ffd41cbcf40 RSI: 0000000000000000 RDI: 00007ffd41cbcf40
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001514030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005

Showing all locks held in the system:
1 lock held by khungtaskd/1008:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff814833c8>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4541
1 lock held by rsyslogd/6861:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff8193e96b>] __fdget_pos+0xab/0xd0 fs/file.c:769
2 locks held by getty/6984:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861a27f3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83105446>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6985:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861a27f3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83105446>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6986:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861a27f3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83105446>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6987:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861a27f3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83105446>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6988:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861a27f3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83105446>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6989:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861a27f3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83105446>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6990:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861a27f3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83105446>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.3/18440:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a34c6>] __blkdev_put+0xa6/0x7f0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8372dd50>] lo_release+0x20/0x1b0 drivers/block/loop.c:1666
2 locks held by syz-executor.2/1739:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a3d55>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8372918d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623
2 locks held by syz-executor.5/1744:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a34c6>] __blkdev_put+0xa6/0x7f0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8372dd50>] lo_release+0x20/0x1b0 drivers/block/loop.c:1666
2 locks held by syz-executor.3/1746:
 #0:  (loop_index_mutex){+.+.}, at: [<ffffffff8372f565>] loop_control_ioctl+0x65/0x2f0 drivers/block/loop.c:1982
 #1:  (&lo->lo_ctl_mutex#2){+.+.}, at: [<ffffffff8372f653>] loop_control_ioctl+0x153/0x2f0 drivers/block/loop.c:1996
2 locks held by syz-executor.0/1751:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff8372f9df>] lo_ioctl+0x8f/0x1ce0 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff82ca41cf>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
1 lock held by blkid/1748:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a4d5b>] blkdev_put+0x2b/0x510 fs/block_dev.c:1814
2 locks held by blkid/1750:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a3d55>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8372918d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623
1 lock held by syz-executor.1/1762:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a3d55>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
2 locks held by syz-executor.4/1760:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a3d55>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8372918d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623
2 locks held by blkid/1761:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a3d55>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8372918d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623
1 lock held by blkid/1766:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a3d55>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1008 Comm: khungtaskd Not tainted 4.14.125 #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x19c lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e7/0xb90 kernel/hung_task.c:274
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6859 Comm: rs:main Q:Reg Not tainted 4.14.125 #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880764fc080 task.stack: ffff888092498000
RIP: 0010:file_check_and_advance_wb_err+0x0/0x380 mm/filemap.c:608
RSP: 0018:ffff88809249fac0 EFLAGS: 00000296
RAX: ffffed1012493f36 RBX: ffff8880763cb9f8 RCX: ffff8880764fc900
RDX: 0000000000000000 RSI: ffffffff8778f1e0 RDI: ffff8880952b7a80
RBP: ffff88809249faf0 R08: ffff8880764fc080 R09: ffff8880764fc948
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880952b7a80
R13: 0000000000000000 R14: 00000000006e4de4 R15: 00000000006e51e3
FS:  00007f619d310700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001ef23a0 CR3: 0000000078ebe000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __generic_file_fsync+0x79/0x1a0 fs/libfs.c:977
 ext4_sync_file+0x755/0x12d0 fs/ext4/fsync.c:120
 vfs_fsync_range+0x10e/0x260 fs/sync.c:196
 generic_write_sync include/linux/fs.h:2675 [inline]
 ext4_file_write_iter+0x68a/0xe90 fs/ext4/file.c:275
 call_write_iter include/linux/fs.h:1777 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x4a7/0x6b0 fs/read_write.c:482
 vfs_write+0x198/0x500 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xfd/0x230 fs/read_write.c:582
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f619ed6e19d
RSP: 002b:00007f619d30ef90 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000400 RCX: 00007f619ed6e19d
RDX: 0000000000000400 RSI: 0000000001ebba90 RDI: 0000000000000005
RBP: 0000000001ebba90 R08: 00007f61940010d0 R09: 00007f619e6ec9e0
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f619d30f410 R14: 00007f61940010d0 R15: 0000000001ebb890
Code: 45 d4 4c 89 4d d8 e8 d0 ed 16 00 8b 4d d0 44 8b 45 d4 4c 8b 4d d8 eb 8e e8 be ed 16 00 e9 33 ff ff ff 66 0f 1f 84 00 00 00 00 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 89 fb 4c 8d bb c0 01