Buffer I/O error on dev loop0, logical block 0, async page read
INFO: task syz-executor7:25067 blocked for more than 120 seconds.
      Not tainted 4.14.0-rc5-next-20171018+ #8
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D22640 25067   3305 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2798 [inline]
 __schedule+0x8eb/0x2060 kernel/sched/core.c:3374
 schedule+0xf5/0x430 kernel/sched/core.c:3433
 io_schedule+0x1c/0x70 kernel/sched/core.c:5041
 wait_on_page_bit_common+0x4b3/0x770 mm/filemap.c:1100
 wait_on_page_bit mm/filemap.c:1133 [inline]
 wait_on_page_locked include/linux/pagemap.h:533 [inline]
 __lock_page_or_retry+0x3f7/0x4f0 mm/filemap.c:1310
 lock_page_or_retry include/linux/pagemap.h:513 [inline]
 filemap_fault+0xcfa/0x1d30 mm/filemap.c:2532
 __do_fault+0xeb/0x30f mm/memory.c:3196
 do_read_fault mm/memory.c:3606 [inline]
 do_fault mm/memory.c:3706 [inline]
 handle_pte_fault mm/memory.c:3936 [inline]
 __handle_mm_fault+0x1b9b/0x39c0 mm/memory.c:4060
 handle_mm_fault+0x334/0x8d0 mm/memory.c:4097
 faultin_page mm/gup.c:502 [inline]
 __get_user_pages+0x50c/0x15f0 mm/gup.c:699
 populate_vma_page_range+0x20e/0x2f0 mm/gup.c:1152
 __mm_populate+0x23a/0x450 mm/gup.c:1202
 mm_populate include/linux/mm.h:2208 [inline]
 vm_mmap_pgoff+0x241/0x280 mm/util.c:338
 SYSC_mmap_pgoff mm/mmap.c:1518 [inline]
 SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1476
 SYSC_mmap arch/x86/kernel/sys_x86_64.c:99 [inline]
 SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:90
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x447c89
RSP: 002b:00007ff26291cbd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ff26291d6cc RCX: 0000000000447c89
RDX: 0000000000000001 RSI: 0000000000002000 RDI: 0000000020000000
RBP: 0000000000000082 R08: 0000000000000017 R09: 0000000000000000
R10: 0000000000002011 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff26291d9c0 R15: 00007ff26291d700

Showing all locks held in the system:
2 locks held by khungtaskd/637:
 #0:  (rcu_read_lock){....}, at: [<ffffffff816fb525>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0:  (rcu_read_lock){....}, at: [<ffffffff816fb525>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249
 #1:  (tasklist_lock){.+.+}, at: [<ffffffff8154b243>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4541
1 lock held by rsyslogd/2879:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff81b3b4ab>] __fdget_pos+0x12b/0x190 fs/file.c:767
2 locks held by getty/2962:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff84e54287>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff827fbe0f>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2133
2 locks held by getty/2963:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff84e54287>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff827fbe0f>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2133
2 locks held by getty/2964:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff84e54287>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff827fbe0f>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2133
2 locks held by getty/2965:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff84e54287>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff827fbe0f>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2133
2 locks held by getty/2966:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff84e54287>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff827fbe0f>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2133
2 locks held by getty/2967:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff84e54287>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff827fbe0f>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2133
2 locks held by getty/13940:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff84e54287>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff827fbe0f>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2133

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

NMI backtrace for cpu 3
CPU: 3 PID: 637 Comm: khungtaskd Not tainted 4.14.0-rc5-next-20171018+ #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 nmi_cpu_backtrace+0x20e/0x240 lib/nmi_backtrace.c:102
 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:61
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 trigger_all_cpu_backtrace include/linux/nmi.h:137 [inline]
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x90c/0xd60 kernel/hung_task.c:249
 kthread+0x38b/0x470 kernel/kthread.c:242
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
Sending NMI from CPU 3 to CPUs 0-2:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff84e54ea6
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff84e54ea6
NMI backtrace for cpu 2 skipped: idling at pc 0xffffffff84e54ea6