INFO: task syz-executor.0:2090 blocked for more than 140 seconds.
      Not tainted 4.9.194+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D24760  2090      1 0x00000004
 0000000000000083 ffff8801d992df00 0000000000000000 ffff8801db621000
 ffffffff83031180 ffff8801db621018 ffff8801a680f988 ffffffff8281af8e
 ffffffff830c3120 ffff8801a680f9a8 00ff8801a680f8d8 ffff8801db6218f0
Call Trace:
 [<000000006c0dc69b>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<00000000afe013e0>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579
 [<00000000a015b1aa>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<00000000a015b1aa>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621
 [<00000000164bbb81>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
 [<000000000a4a588d>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:637
 [<0000000055ef9cab>] loop_clr_fd+0x7dd/0xa60 drivers/block/loop.c:1081
 [<00000000f5e16aad>] lo_ioctl+0x7e9/0x1b10 drivers/block/loop.c:1414
 [<00000000a766a875>] __blkdev_driver_ioctl block/ioctl.c:294 [inline]
 [<00000000a766a875>] blkdev_ioctl+0xe14/0x19e0 block/ioctl.c:590
 [<00000000ce16c6b1>] block_ioctl+0xde/0x120 fs/block_dev.c:1696
 [<00000000f899c7ea>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<00000000f899c7ea>] file_ioctl fs/ioctl.c:493 [inline]
 [<00000000f899c7ea>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677
 [<0000000060fe09a1>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<0000000060fe09a1>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<0000000090cadfc3>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<00000000974bac9d>] 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: [<00000000e61b141c>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<00000000e61b141c>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<00000000efb5d537>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1890:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<00000000053f0889>] __fdget_pos+0xa8/0xd0 fs/file.c:782
2 locks held by getty/2018:
 #0:  (&tty->ldisc_sem){++++++}, at: [<000000001854dbab>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<0000000033283f32>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.0/2090:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<000000005f4ff9c5>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000164bbb81>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
2 locks held by syz-executor.4/22366:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000092f56c8>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000376301ab>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621
2 locks held by syz-executor.2/22385:
 #0:  (loop_index_mutex){+.+.+.}, at: [<000000003872e41c>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
 #1:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<00000000c39e94fc>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987
1 lock held by syz-executor.2/22389:
 #0:  (loop_index_mutex){+.+.+.}, at: [<000000003872e41c>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
2 locks held by blkid/22386:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000092f56c8>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000376301ab>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0
 ffff8801d98d7cc8 ffffffff81b67001 0000000000000001 0000000000000000
 0000000000000001 ffffffff81099d01 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b7229c 0000000000000001 0000000000000000 0000000000000001
Call Trace:
 [<00000000d15ec990>] __dump_stack lib/dump_stack.c:15 [inline]
 [<00000000d15ec990>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<00000000f387bb34>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<0000000097ff2af5>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<00000000ae69280f>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<00000000ecdc3b41>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<00000000ecdc3b41>] check_hung_task kernel/hung_task.c:126 [inline]
 [<00000000ecdc3b41>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<00000000ecdc3b41>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<0000000074ccc938>] kthread+0x278/0x310 kernel/kthread.c:211
 [<00000000a31d6179>] 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 0xffffffff8282a0e1