TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
IPVS: Creating netns size=2536 id=45
INFO: task syz-executor0:11891 blocked for more than 140 seconds.
      Not tainted 4.9.122-g54068d6 #26
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D27512 11891      1 0x00000004
 ffff8801b91c6000 0000000000000000 ffff8801ca7b9f80 ffffffff84629800
 ffff8801db221c18 ffff8801a8e8f4c8 ffffffff839efdcd ffff8801b91c68c8
 ffffed0037238d18 ffff8801b91c6000 00fffc0000000000 ffff8801db2224e8
Call Trace:
 [<ffffffff839f13cf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839f1d53>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff839f61d6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839f61d6>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff818de3f1>] vfat_lookup+0xd1/0x530 fs/fat/namei_vfat.c:729
 [<ffffffff8159889e>] lookup_slow+0x23e/0x470 fs/namei.c:1668
 [<ffffffff815a4e26>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a6b49>] link_path_walk+0x889/0x1200 fs/namei.c:2120
 [<ffffffff815a7bbd>] path_openat+0x1ad/0x3590 fs/namei.c:3533
 [<ffffffff815af267>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff81571a3d>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff81571d1d>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff81571d1d>] SyS_open+0x2d/0x40 fs/open.c:1085
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff83a00cd3>] 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: [<ffffffff81368a5c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81368a5c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff814282c8>] 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: [<ffffffff815dbb4c>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff815767be>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff815767be>] vfs_write+0x3ae/0x530 fs/read_write.c:556
2 locks held by getty/3771:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fee72>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82124562>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
2 locks held by syz-executor0/11891:
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815987a1>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815987a1>] lookup_slow+0x141/0x470 fs/namei.c:1645
 #1:  (&sbi->s_lock){+.+.+.}, at: [<ffffffff818de3f1>] vfat_lookup+0xd1/0x530 fs/fat/namei_vfat.c:729
1 lock held by syz-executor0/17842:
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815987a1>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815987a1>] lookup_slow+0x141/0x470 fs/namei.c:1645

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.122-g54068d6 #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d861fd08 ffffffff81eb8829 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9fa0 ffff8801d861fd40
 ffffffff81ec3b67 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb8829>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb8829>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ec3b67>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ec3afa>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810ba0a4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81368ff4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81368ff4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368ff4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368ff4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119f38d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a00e9c>] 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
CPU: 1 PID: 17800 Comm: syz-executor0 Not tainted 4.9.122-g54068d6 #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019a27c800 task.stack: ffff8801d9018000
RIP: 0010:[<ffffffff81f202bc>] 
c [<ffffffff81f202bc>] check_preemption_disabled+0x4c/0x170 lib/smp_processor_id.c:52
RSP: 0018:ffff8801d901f000  EFLAGS: 00000046
RAX: 0000000080000000 RBX: 0000000000000001 RCX: ffffc9000409d000
RDX: 0000000000040000 RSI: ffffffff81f2028c RDI: ffffffff83e2e820
RBP: ffff8801d901f030 R08: ffff88019a27d138 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003344fa22 R12: ffffffff83e2e820
R13: ffffffff83ccebe0 R14: ffff880195407690 R15: 0000000000000005
FS:  00007ff8458e4700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001263000 CR3: 00000001b9ac8000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffffffff843bd759
c ffffffff83ccebe0
c ffff880195407690
c dffffc0000000000
c
 ffff880195407690
c 0000000000000005
c ffff8801d901f048
c ffffffff81f2041c
c
 0000000000000005
c ffff8801d901f098
c ffffffff81627e75
c 0000020006ec8680
c
Call Trace:
 [<ffffffff81f2041c>] __this_cpu_preempt_check+0x1c/0x20 lib/smp_processor_id.c:62
 [<ffffffff81627e75>] lookup_bh_lru fs/buffer.c:1327 [inline]
 [<ffffffff81627e75>] __find_get_block+0x75/0x4c0 fs/buffer.c:1356
 [<ffffffff81628e49>] __getblk_slow fs/buffer.c:1101 [inline]
 [<ffffffff81628e49>] __getblk_gfp+0x189/0x710 fs/buffer.c:1386
 [<ffffffff8162c7ed>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818bb8b8>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818bb8b8>] fat__get_entry+0x4c8/0x8f0 fs/fat/dir.c:100
 [<ffffffff818c36b7>] fat_get_entry fs/fat/dir.c:128 [inline]
 [<ffffffff818c36b7>] fat_search_long+0x277/0x1180 fs/fat/dir.c:477
 [<ffffffff818ddc24>] vfat_find+0x134/0x180 fs/fat/namei_vfat.c:708
 [<ffffffff818de401>] vfat_lookup+0xe1/0x530 fs/fat/namei_vfat.c:731
 [<ffffffff8159889e>] lookup_slow+0x23e/0x470 fs/namei.c:1668
 [<ffffffff815a4e26>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a6b49>] link_path_walk+0x889/0x1200 fs/namei.c:2120
 [<ffffffff815a7bbd>] path_openat+0x1ad/0x3590 fs/namei.c:3533
 [<ffffffff815af267>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff81571a3d>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff81571d60>] SYSC_openat fs/open.c:1099 [inline]
 [<ffffffff81571d60>] SyS_openat+0x30/0x40 fs/open.c:1093
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff83a00cd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c0f 
c7e 
c65 
c8b 
c05 
cb6 
c7a 
c0f 
c7e 
ca9 
cff 
cff 
cff 
c7f 
c74 
c1b 
ce8 
cca 
c0a 
c44 
cff 
ce8 
cc5 
c0a 
c44 
cff 
c89 
cd8 
c48 
c83 
cc4 
c08 
c5b 
c41 
c5c 
c41 
c5d 
c41 
c5e 
c41 
c5f 
c5d 
cc3 
c<e8> 
caf 
c0a 
c44 
cff 
c9c 
c58 
c0f 
c1f 
c44 
c00 
c00 
cf6 
cc4 
c02 
c74 
cd9 
ce8 
c9e 
c0a 
c44 
c