IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth3: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth2: link becomes ready
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=13578 comm=syz-executor4
INFO: task syz-executor5:13579 blocked for more than 140 seconds.
      Not tainted 4.9.124-g09eb2ba #31
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D28928 13579   3869 0x00000004
 ffff880196eae000 0000000000000000 ffff8801cc559a40 ffff8801d9ae9800
 ffff8801db221c18 ffff8801ab0e7b58 ffffffff839f0afd 0000000000000002
 0000000041b58ab3 ffffffff843bbc94 00ffffff81223870 ffff8801db2224e8
Call Trace:
 [<ffffffff839f20ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff816073d9>] wb_wait_for_completion+0x149/0x1b0 fs/fs-writeback.c:221
 [<ffffffff8160cb69>] sync_inodes_sb+0x1a9/0x8d0 fs/fs-writeback.c:2412
 [<ffffffff8161ec93>] sync_inodes_one_sb+0x43/0x60 fs/sync.c:73
 [<ffffffff81581590>] iterate_supers+0x130/0x260 fs/super.c:593
 [<ffffffff8161f5a2>] sys_sync+0xa2/0x170 fs/sync.c:112
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff83a019d3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/520:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813689dc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813689dc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81428248>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3761:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839ffba2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82125402>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor5/13579:
 #0:  (&type->s_umount_key#48){++++..}, at: [<ffffffff81581541>] iterate_supers+0xe1/0x260 fs/super.c:591
1 lock held by syz-executor5/13611:
 #0:  (&type->s_umount_key#48){++++..}, at: [<ffffffff81581541>] iterate_supers+0xe1/0x260 fs/super.c:591

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

NMI backtrace for cpu 1
CPU: 1 PID: 520 Comm: khungtaskd Not tainted 4.9.124-g09eb2ba #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d976fd08 ffffffff81eb95e9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9fa0 ffff8801d976fd40
 ffffffff81ec4927 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ec4927>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ec48ba>] 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
 [<ffffffff81368f74>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81368f74>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368f74>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368f74>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01b9c>] 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: 5305 Comm: kworker/u4:7 Not tainted 4.9.124-g09eb2ba #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn
c (flush-7:0)
c
task: ffff8801caafb000 task.stack: ffff8801c42e8000
RIP: 0010:[<ffffffff81629e16>] 
c [<ffffffff81629e16>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff81629e16>] 
c [<ffffffff81629e16>] compound_head include/linux/page-flags.h:143 [inline]
RIP: 0010:[<ffffffff81629e16>] 
c [<ffffffff81629e16>] put_page include/linux/mm.h:782 [inline]
RIP: 0010:[<ffffffff81629e16>] 
c [<ffffffff81629e16>] grow_dev_page fs/buffer.c:1044 [inline]
RIP: 0010:[<ffffffff81629e16>] 
c [<ffffffff81629e16>] grow_buffers fs/buffer.c:1078 [inline]
RIP: 0010:[<ffffffff81629e16>] 
c [<ffffffff81629e16>] __getblk_slow fs/buffer.c:1105 [inline]
RIP: 0010:[<ffffffff81629e16>] 
c [<ffffffff81629e16>] __getblk_gfp+0x4b6/0x710 fs/buffer.c:1386
RSP: 0018:ffff8801c42ef6a0  EFLAGS: 00000286
RAX: ffffea000712fba0 RBX: 0000000000000001 RCX: ffffed003885debe
RDX: 1ffffffff08c149a RSI: ffffea000712fb80 RDI: 0000000000000000
RBP: ffff8801c42ef730 R08: ffff8801caafb988 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003955f72c R12: 0000000000000200
R13: ffffea000712fb80 R14: 0000000000000200 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f25f01a1019 CR3: 00000001c11c4000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 00000000200001c0 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff880198c20148
c ffff8801d5d89708
c ffffea000712fb9c
c ffffed003abb12e1
c
 ffff8801d5ede2a0
c ffff8801d5d898c0
c ffffea000712fba0
c 0000000000000000
c
 ffff8801d5d89890
c 00000008caafb940
c 0000000000000001
c 0000000000000000
c
Call Trace:
 [<ffffffff8162d48d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818db771>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818db771>] fat_clusters_flush+0x111/0x380 fs/fat/misc.c:69
 [<ffffffff818d56d2>] fat_write_inode+0xf2/0x170 fs/fat/inode.c:898
 [<ffffffff81606add>] write_inode fs/fs-writeback.c:1180 [inline]
 [<ffffffff81606add>] __writeback_single_inode+0x86d/0x1020 fs/fs-writeback.c:1379
 [<ffffffff81607ddc>] writeback_sb_inodes+0x4ac/0xe70 fs/fs-writeback.c:1584
 [<ffffffff8160889b>] __writeback_inodes_wb+0xfb/0x1e0 fs/fs-writeback.c:1653
 [<ffffffff81609022>] wb_writeback+0x512/0xbd0 fs/fs-writeback.c:1762
 [<ffffffff8161230e>] wb_do_writeback fs/fs-writeback.c:1894 [inline]
 [<ffffffff8161230e>] wb_workfn+0x20e/0xdb0 fs/fs-writeback.c:1930
 [<ffffffff8118f461>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff81190256>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01b9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
c08 
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c48 
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c<48> 
cc1 
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c00 
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c