INFO: task syz-executor.1:11075 blocked for more than 140 seconds.
      Not tainted 4.9.202+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D25544 11075      1 0x10000004
 0000000000000083 ffff8801d1e217c0 ffff8801d11b7900 ffff8801db71ffc0
 ffff8801d10217c0 ffff8801db71ffd8 ffff8801a3dc7688 ffffffff8280a1de
 ffff8801d1e217c0 ffffffff841f6b00 00ff8801a3dc75e8 ffff8801db7208b0
Call Trace:
 [<00000000e4039e7f>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<00000000006fd43e>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579
 [<0000000031d34f30>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<0000000031d34f30>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621
 [<000000007259377c>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
 [<00000000e88f9262>] __blkdev_get+0x268/0xeb0 fs/block_dev.c:1287
 [<00000000dd66da17>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424
 [<000000005863fdba>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579
 [<0000000091926a19>] do_dentry_open+0x422/0xd20 fs/open.c:791
 [<000000000f073d72>] vfs_open+0x105/0x230 fs/open.c:904
 [<0000000059fc8ca7>] do_last fs/namei.c:3457 [inline]
 [<0000000059fc8ca7>] path_openat+0xbf5/0x2f60 fs/namei.c:3581
 [<000000002544a1be>] do_filp_open+0x1a1/0x280 fs/namei.c:3615
 [<000000004a51ef4d>] do_sys_open+0x2f0/0x610 fs/open.c:1097
 [<000000002d725812>] SYSC_open fs/open.c:1115 [inline]
 [<000000002d725812>] SyS_open+0x2d/0x40 fs/open.c:1110
 [<00000000a2487fc8>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<0000000017974343>] 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: [<00000000c1c67e0a>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<00000000c1c67e0a>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.?..}, at: [<00000000e837abdc>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339
2 locks held by getty/2026:
 #0:  (&tty->ldisc_sem){++++++}, at: [<00000000f4f78403>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<000000002cf97ed6>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.1/11075:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d034383b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<000000007259377c>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
1 lock held by syz-executor.2/11549:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d034383b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
2 locks held by syz-executor.3/13933:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d034383b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<000000007259377c>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
2 locks held by syz-executor.4/15680:
 #0:  (loop_index_mutex){+.+.+.}, at: [<00000000cb854ed2>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1974
 #1:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<000000006196e153>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1988
2 locks held by syz-executor.0/15657:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<0000000014cbf667>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<000000008aa9dad4>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
2 locks held by blkid/15675:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d034383b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<000000007259377c>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
2 locks held by blkid/15682:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d034383b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<000000007259377c>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.202+ #0
 ffff8801d98d7cc8 ffffffff81b55d2b 0000000000000001 0000000000000000
 0000000000000001 ffffffff8109a001 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b60fcc 0000000000000001 0000000000000000 0000000000000001
Call Trace:
 [<000000008d6c4d1c>] __dump_stack lib/dump_stack.c:15 [inline]
 [<000000008d6c4d1c>] dump_stack+0xcb/0x130 lib/dump_stack.c:56
 [<00000000131ab4eb>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<000000005e1c4099>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<0000000058f82690>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<000000007e9ff9c2>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<000000007e9ff9c2>] check_hung_task kernel/hung_task.c:126 [inline]
 [<000000007e9ff9c2>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<000000007e9ff9c2>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<00000000ae591d2e>] kthread+0x278/0x310 kernel/kthread.c:211
 [<000000008e6f1b31>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff82819331