syzbot

IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready
8021q: adding VLAN 0 to HW filter on device bond0
IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
bond0 (unregistering): Released all slaves
INFO: task syz-executor4:23698 blocked for more than 120 seconds.
      Not tainted 4.16.0-rc7+ #368
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D21744 23698   4346 0x80000006
Call Trace:
 context_switch kernel/sched/core.c:2862 [inline]
 __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440
 schedule+0xf5/0x430 kernel/sched/core.c:3499
 io_schedule+0x1c/0x70 kernel/sched/core.c:5115
 wait_on_page_bit_common+0x4b3/0x770 mm/filemap.c:1099
 wait_on_page_bit mm/filemap.c:1132 [inline]
 wait_on_page_writeback include/linux/pagemap.h:546 [inline]
 __filemap_fdatawait_range+0x282/0x430 mm/filemap.c:533
 filemap_fdatawait_range mm/filemap.c:558 [inline]
 filemap_fdatawait include/linux/fs.h:2591 [inline]
 filemap_write_and_wait+0x7a/0xd0 mm/filemap.c:624
 __sync_blockdev fs/block_dev.c:448 [inline]
 sync_blockdev.part.30+0x50/0x70 fs/block_dev.c:457
 sync_blockdev fs/block_dev.c:444 [inline]
 __blkdev_put+0x18b/0x760 fs/block_dev.c:1781
 blkdev_put+0x85/0x4f0 fs/block_dev.c:1850
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1857
 __fput+0x327/0x7e0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x199/0x270 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9bb/0x1ad0 kernel/exit.c:865
 do_group_exit+0x149/0x400 kernel/exit.c:968
 get_signal+0x73a/0x16d0 kernel/signal.c:2469
 do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x454889
RSP: 002b:00007f2c78d12c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000128
RAX: 0000000000004000 RBX: 00007f2c78d136d4 RCX: 0000000000454889
RDX: 0000000000000005 RSI: 0000000020000200 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000484 R14: 00000000006f8d00 R15: 0000000000000000

Showing all locks held in the system:
2 locks held by khungtaskd/869:
 #0:  (rcu_read_lock){....}, at: [<0000000010eaf44c>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0:  (rcu_read_lock){....}, at: [<0000000010eaf44c>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249
 #1:  (tasklist_lock){.+.+}, at: [<0000000077e6302c>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470
1 lock held by rsyslogd/4180:
 #0:  (&f->f_pos_lock){+.+.}, at: [<00000000a77800ba>] __fdget_pos+0x12b/0x190 fs/file.c:765
2 locks held by getty/4271:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000e19e2e29>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000321ffd20>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4272:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000e19e2e29>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000321ffd20>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4273:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000e19e2e29>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000321ffd20>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4274:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000e19e2e29>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000321ffd20>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4275:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000e19e2e29>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000321ffd20>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4276:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000e19e2e29>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000321ffd20>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4277:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000e19e2e29>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000321ffd20>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
3 locks held by kworker/u4:5/6805:
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<00000000f4d5ab7c>] work_static include/linux/workqueue.h:198 [inline]
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<00000000f4d5ab7c>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<00000000f4d5ab7c>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<00000000f4d5ab7c>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084
 #1:  ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<00000000ca26067d>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088
 #2:  (&type->s_umount_key#33){.+.+}, at: [<00000000bbf8d558>] trylock_super+0x20/0x100 fs/super.c:395
1 lock held by syz-executor4/23698:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000eebf3347>] __blkdev_put+0xbc/0x760 fs/block_dev.c:1775
1 lock held by blkid/23747:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<000000006a790609>] __blkdev_get+0x176/0x13b0 fs/block_dev.c:1458
1 lock held by syz-executor4/23908:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<000000006a790609>] __blkdev_get+0x176/0x13b0 fs/block_dev.c:1458

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

NMI backtrace for cpu 0
CPU: 0 PID: 869 Comm: khungtaskd Not tainted 4.16.0-rc7+ #368
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x123/0x180 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:138 [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+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54