INFO: task syz-executor3:3872 blocked for more than 120 seconds.
      Not tainted 4.9.97-g2bcbbd5 #11
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D27960  3872   3864 0x00000000
 ffff8801b6686000 ffff8801cfae24c0 ffff8801c5a85500 ffff880197109800
 ffff8801db321b98 ffff88019d2174e8 ffffffff839e375d ffff8801b66868c8
 ffffed0036cd0d18 ffff8801b6686000 00fffc0000000000 ffff8801db322468
Call Trace:
 [<ffffffff839e4d5f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839e56e3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590
 [<ffffffff839e9b66>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839e9b66>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff825c9ad4>] loop_probe+0x74/0x180 drivers/block/loop.c:1886
 [<ffffffff8256ee63>] kobj_lookup+0x223/0x410 drivers/base/map.c:124
 [<ffffffff81e57a19>] get_gendisk+0x39/0x2d0 block/genhd.c:716
 [<ffffffff8162ec81>] __blkdev_get+0x351/0xd60 fs/block_dev.c:1262
 [<ffffffff81631f2a>] blkdev_get+0x2da/0x920 fs/block_dev.c:1416
 [<ffffffff81632785>] blkdev_open+0x1a5/0x250 fs/block_dev.c:1571
 [<ffffffff81567583>] do_dentry_open+0x703/0xc80 fs/open.c:766
 [<ffffffff8156ad6c>] vfs_open+0x11c/0x210 fs/open.c:879
 [<ffffffff815a1ea8>] do_last fs/namei.c:3410 [inline]
 [<ffffffff815a1ea8>] path_openat+0x758/0x3590 fs/namei.c:3534
 [<ffffffff815a8fa7>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff8156b77d>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff8156ba5d>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8156ba5d>] SyS_open+0x2d/0x40 fs/open.c:1085
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4653>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/518:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646ec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646ec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423ce0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3673:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d579c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3769:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f2802>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211c8a2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor3/3872:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c9ad4>] loop_probe+0x74/0x180 drivers/block/loop.c:1886
1 lock held by syz-executor2/8822:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
2 locks held by syz-executor7/8824:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
 #1:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<ffffffff825c98e6>] loop_control_ioctl+0x186/0x300 drivers/block/loop.c:1920
1 lock held by syz-executor7/8862:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
2 locks held by syz-executor7/8866:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162ea3c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c229b>] lo_open+0x1b/0xa0 drivers/block/loop.c:1555
2 locks held by syz-executor0/8826:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825c71fb>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81e531ee>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
1 lock held by syz-executor0/8863:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162ea3c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
1 lock held by syz-executor6/8830:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
1 lock held by syz-executor6/8864:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
1 lock held by syz-executor6/8865:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
2 locks held by syz-executor6/8867:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162ea3c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c229b>] lo_open+0x1b/0xa0 drivers/block/loop.c:1555
2 locks held by blkid/8834:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162ea3c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c229b>] lo_open+0x1b/0xa0 drivers/block/loop.c:1555
1 lock held by syz-executor5/8842:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
1 lock held by syz-executor5/8870:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
1 lock held by syz-executor5/8871:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
1 lock held by syz-executor5/8872:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c97da>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906

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

NMI backtrace for cpu 0
CPU: 0 PID: 518 Comm: khungtaskd Not tainted 4.9.97-g2bcbbd5 #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d938fd08 ffffffff81eb0b69 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b7d60 ffff8801d938fd40
 ffffffff81ebbe97 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb0b69>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb0b69>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebbe97>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebbe2a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7e64>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364c84>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364c84>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364c84>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364c84>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad5d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f481c>] 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 skipped: idling at pc 0xffffffff839f3266