IPVS: stopping master sync thread 26373 ...
IPVS: stopping backup sync thread 26372 ...
INFO: task syz-executor7:26387 blocked for more than 140 seconds.
      Not tainted 4.9.112-g9e79039 #7
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D29048 26387  11990 0x00000004
 ffff8801a7b5e000 0000000000000000 ffff8801d47a64c0 ffff8801ba929800
 ffff8801db321c18 ffff8801d801fc10 ffffffff839e907d ffffffff81235667
 0000000000000000 ffff8801a7b5e8c0 0000000600000007 ffff8801db3224e8
Call Trace:
 [<ffffffff839ea67f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f4aa4>] rwsem_down_read_failed+0x1e4/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81ee74f8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff839f39d2>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff839f39d2>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8157cdb1>] iterate_supers+0xe1/0x260 fs/super.c:591
 [<ffffffff8161adf2>] sys_sync+0xa2/0x170 fs/sync.c:112
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] 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: [<ffffffff8136675c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136675c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425de7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/3679:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d818c>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff81572cce>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff81572cce>] vfs_write+0x3ae/0x530 fs/read_write.c:556
1 lock held by rsyslogd/3681:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d818c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3777:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f8122>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211edc2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor7/26387:
 #0:  (&type->s_umount_key#41){++++..}, at: [<ffffffff8157cdb1>] iterate_supers+0xe1/0x260 fs/super.c:591
1 lock held by syz-executor1/26395:
 #0:  (&type->s_umount_key#40/1){+.+.+.}, at: [<ffffffff8157b9f2>] alloc_super fs/super.c:241 [inline]
 #0:  (&type->s_umount_key#40/1){+.+.+.}, at: [<ffffffff8157b9f2>] sget_userns+0x552/0xba0 fs/super.c:503
1 lock held by syz-executor1/26420:
 #0:  (&type->s_umount_key#40/1){+.+.+.}, at: [<ffffffff8157b9f2>] alloc_super fs/super.c:241 [inline]
 #0:  (&type->s_umount_key#40/1){+.+.+.}, at: [<ffffffff8157b9f2>] sget_userns+0x552/0xba0 fs/super.c:503

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.112-g9e79039 #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d86d7d08 ffffffff81eb3249 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d86d7d40
 ffffffff81ebe547 0000000000000000 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81eb3249>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3249>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebe547>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebe4da>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366cf4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366cf4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366cf4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366cf4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0bd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fa11c>] 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 0xffffffff839f8b86