IPVS: stopping backup sync thread 10284 ...
INFO: task syz-executor0:8501 blocked for more than 140 seconds.
      Not tainted 4.9.119-g9dc978d #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D27016  8501      1 0x00000004
 ffff8801a4fdb000 0000000000000000 ffff8801d75e9f80 ffff8801d9a6b000
 ffff8801db321c18 ffff8801a3aa74c8 ffffffff839ebdcd ffff8801a4fdb8c8
 ffffed00349fb718 ffff8801a4fdb000 00fffc0000000000 ffff8801db3224e8
Call Trace:
 [<ffffffff839ed3cf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839edd53>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff839f21d6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839f21d6>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff818da421>] vfat_lookup+0xd1/0x530 fs/fat/namei_vfat.c:729
 [<ffffffff8159515e>] lookup_slow+0x23e/0x470 fs/namei.c:1668
 [<ffffffff815a16e6>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a3409>] link_path_walk+0x889/0x1200 fs/namei.c:2120
 [<ffffffff815a447d>] path_openat+0x1ad/0x3590 fs/namei.c:3533
 [<ffffffff815abb27>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff8156e2fd>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff8156e5dd>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8156e5dd>] SyS_open+0x2d/0x40 fs/open.c:1085
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] 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: [<ffffffff813667bc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667bc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81426027>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/3673:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d859c>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157307e>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157307e>] vfs_write+0x3ae/0x530 fs/read_write.c:556
2 locks held by getty/3771:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fae72>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821208d2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
2 locks held by syz-executor0/8501:
 #0:  (&sb->s_type->i_mutex_key#18){++++++}, at: [<ffffffff81595061>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#18){++++++}, at: [<ffffffff81595061>] lookup_slow+0x141/0x470 fs/namei.c:1645
 #1:  (&sbi->s_lock){+.+.+.}, at: [<ffffffff818da421>] vfat_lookup+0xd1/0x530 fs/fat/namei_vfat.c:729

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d84f7d08 ffffffff81eb4be9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9bd0 ffff8801d84f7d40
 ffffffff81ebfee7 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4be9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4be9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebfee7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebfe7a>] 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
 [<ffffffff81366d54>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d54>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d54>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d54>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fce9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 19609 Comm: syz-executor0 Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d3eb4800 task.stack: ffff8801a66e0000
RIP: 0010:[<ffffffff8135eb0b>] 
c [<ffffffff8135eb0b>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff8135eb0b>] 
c [<ffffffff8135eb0b>] __sanitizer_cov_trace_pc+0x3b/0x50 kernel/kcov.c:105
RSP: 0018:ffff8801a66e7840  EFLAGS: 00000246
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc9000e709000
RDX: 000000000003ffff RSI: ffffffff81621d21 RDI: ffff88019cf039e0
RBP: ffff8801a66e7840 R08: ffff8801d3eb5160 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003a7d6a27 R12: 0000000000000043
R13: ffff88019cf03b28 R14: ffff8801d61a4ac0 R15: ffff88019cf03930
FS:  00007fbec3201700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001759b10 CR3: 00000001cb818000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Stack:
 ffff8801a66e7890
c ffffffff81621d21
c 0000000008100000
c 0000000000000001
c
 0000000000040800
c 0000000000000003
c 0000000000000200
c ffffea00075756c0
c
 0000000000000200
c dffffc0000000000
c ffff8801a66e7930
c ffffffff81625b39
c
Call Trace:
 [<ffffffff81621d21>] init_page_buffers+0x251/0x350 fs/buffer.c:969
 [<ffffffff81625b39>] grow_dev_page fs/buffer.c:1014 [inline]
 [<ffffffff81625b39>] grow_buffers fs/buffer.c:1078 [inline]
 [<ffffffff81625b39>] __getblk_slow fs/buffer.c:1105 [inline]
 [<ffffffff81625b39>] __getblk_gfp+0x579/0x710 fs/buffer.c:1386
 [<ffffffff816290ed>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818b78e8>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818b78e8>] fat__get_entry+0x4c8/0x8f0 fs/fat/dir.c:100
 [<ffffffff818c095c>] fat_get_entry fs/fat/dir.c:128 [inline]
 [<ffffffff818c095c>] __fat_readdir+0x36c/0x1840 fs/fat/dir.c:589
 [<ffffffff818c1e71>] fat_readdir+0x41/0x50 fs/fat/dir.c:703
 [<ffffffff815b42fc>] iterate_dir+0x1ac/0x600 fs/readdir.c:50
 [<ffffffff815b533c>] SYSC_getdents fs/readdir.c:230 [inline]
 [<ffffffff815b533c>] SyS_getdents+0x13c/0x2a0 fs/readdir.c:211
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c6c 
c92 
ccb 
c7e 
c81 
ce2 
c00 
c01 
c1f 
c00 
c48 
c8b 
c75 
c08 
c75 
c2b 
c8b 
c90 
c80 
c12 
c00 
c00 
c83 
cfa 
c02 
c75 
c20 
c48 
c8b 
c88 
c88 
c12 
c00 
c00 
c8b 
c80 
c84 
c12 
c00 
c00 
c48 
c8b 
c11 
c<48> 
c83 
cc2 
c01 
c48 
c39 
cd0 
c76 
c07 
c48 
c89 
c34 
cd1 
c48 
c89 
c11 
c5d 
cc3 
c0f 
c1f 
c00 
c