INFO: task syz-executor6:24839 blocked for more than 120 seconds.
      Not tainted 4.9.103-g0cecdf8 #35
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6   D25592 24839   3884 0x00000004
 ffff8801b646c800 ffff8801d6d88540 ffff880188ded500 ffff8801ce160000
 ffff8801db221c18 ffff880181d57240 ffffffff839e711d 0000000000000007
 1ffffffff0886280 0000000000000000 00ffffff81f1af0b ffff8801db2224e8
Call Trace:
 [<ffffffff839e871f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f4b31>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
 [<ffffffff839e68fa>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5180
 [<ffffffff839e9b69>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff839e9b69>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff839e92b3>] __wait_on_bit+0x93/0x120 kernel/sched/wait.c:383
 [<ffffffff81433fd0>] wait_on_page_bit+0x130/0x140 mm/filemap.c:802
 [<ffffffff8143aaf9>] wait_on_page_locked include/linux/pagemap.h:517 [inline]
 [<ffffffff8143aaf9>] wait_on_page_read mm/filemap.c:2379 [inline]
 [<ffffffff8143aaf9>] do_read_cache_page+0x3a9/0x880 mm/filemap.c:2418
 [<ffffffff8143b031>] read_cache_page+0x61/0x80 mm/filemap.c:2500
 [<ffffffff81e62f80>] read_mapping_page include/linux/pagemap.h:373 [inline]
 [<ffffffff81e62f80>] read_pagecache_sector block/partition-generic.c:574 [inline]
 [<ffffffff81e62f80>] read_dev_sector+0xc0/0x2b0 block/partition-generic.c:586
 [<ffffffff81e6b35f>] read_part_sector block/partitions/check.h:37 [inline]
 [<ffffffff81e6b35f>] adfspart_check_ICS+0x11f/0xb60 block/partitions/acorn.c:366
 [<ffffffff81e68bc4>] check_partition+0x344/0x650 block/partitions/check.c:166
 [<ffffffff81e646b8>] rescan_partitions+0x1d8/0x660 block/partition-generic.c:454
 [<ffffffff81e55a84>] __blkdev_reread_part+0x164/0x1f0 block/ioctl.c:170
 [<ffffffff81e55b36>] blkdev_reread_part+0x26/0x40 block/ioctl.c:190
 [<ffffffff825c63fc>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:637
 [<ffffffff825c6e8e>] loop_set_status+0xa7e/0xfe0 drivers/block/loop.c:1171
 [<ffffffff825c788f>] loop_set_status64+0xbf/0x110 drivers/block/loop.c:1280
 [<ffffffff825ca096>] lo_ioctl+0x406/0x1aa0 drivers/block/loop.c:1370
 [<ffffffff81e570a6>] __blkdev_driver_ioctl block/ioctl.c:294 [inline]
 [<ffffffff81e570a6>] blkdev_ioctl+0x7b6/0x1a70 block/ioctl.c:590
 [<ffffffff8163259e>] block_ioctl+0xde/0x120 fs/block_dev.c:1688
 [<ffffffff815b27cc>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b27cc>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b27cc>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b384f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b384f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f8013>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136688c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136688c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425e10>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3681:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d7a4c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3777:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f61c2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211f1d2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor6/24839:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825c9d1b>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81e55b2e>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
1 lock held by syz-executor6/24893:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825c9d1b>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
1 lock held by blkid/24855:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81630cac>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.103-g0cecdf8 #35
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d9127d08 ffffffff81eb34a9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9590 ffff8801d9127d40
 ffffffff81ebe7a7 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb34a9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb34a9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebe7a7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebe73a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9694>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366e24>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366e24>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366e24>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366e24>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119cead>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f81dc>] 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 0xffffffff839f6c26