IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
INFO: task syz-executor0:10421 blocked for more than 120 seconds.
      Not tainted 4.9.101-gaef17a5 #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D25432 10421   7778 0x00000004
 ffff8801d3aae000 ffff8801b704af40 ffff8801be395a40 ffff8801b937e000
 ffff8801db221b98 ffff8801cddbfc10 ffffffff839e39bd ffff88018885b388
 0000000000000000 0000000000000000 0000000000000000 ffff8801db222468
Call Trace:
 [<ffffffff839e4fbf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839ef3e4>] rwsem_down_read_failed+0x1e4/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81ee52b8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff839ee312>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff839ee312>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8157a5f1>] iterate_supers+0xe1/0x260 fs/super.c:591
 [<ffffffff81618412>] sys_sync+0xa2/0x170 fs/sync.c:112
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4893>] 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: [<ffffffff8136477c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136477c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423c90>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3769:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f2a62>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211cd32>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor0/10421:
 #0:  (&type->s_umount_key#23){++++.+}, at: [<ffffffff8157a5f1>] iterate_supers+0xe1/0x260 fs/super.c:591
1 lock held by syz-executor0/10497:
 #0:  (&type->s_umount_key#23){++++.+}, at: [<ffffffff8157a5f1>] iterate_supers+0xe1/0x260 fs/super.c:591

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.101-gaef17a5 #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8b87d08 ffffffff81eb1009 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b7da0 ffff8801d8b87d40
 ffffffff81ebc307 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb1009>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb1009>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebc307>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebc29a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7ea4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364d14>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364d14>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364d14>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364d14>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad9d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f4a5c>] 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: 10411 Comm: syz-executor7 Not tainted 4.9.101-gaef17a5 #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d400b000 task.stack: ffff8801d41f8000
RIP: 0010:[<ffffffff81436e0d>] 
c [<ffffffff81436e0d>] find_get_entry+0x38d/0x540 mm/filemap.c:1094
RSP: 0018:ffff8801d41ff760  EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8801d9c17688 RCX: ffffc90010bbb000
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8801d9c17690
RBP: ffff8801d41ff7b8 R08: ffff8801d400b910 R09: 0000000000000001
R10: ffff8801d400b000 R11: 1ffff1003a80171d R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8801d9c17688
FS:  00007f0448bb0700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f172fb15000 CR3: 000000018a712000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff81436a80
c ffffed003a801718
c ffff8801d400b8c8
c 0000000000000001
c
 ffff8801d9c17690
c 0000000000000000
c ffff8801d9c17688
c 0000000000000001
c
 dffffc0000000000
c 0000000000000000
c ffff8801d9c17688
c ffff8801d41ff810
c
Call Trace:
 [<ffffffff81437efb>] pagecache_get_page+0x4b/0x720 mm/filemap.c:1203
 [<ffffffff816215a2>] find_get_page_flags include/linux/pagemap.h:264 [inline]
 [<ffffffff816215a2>] __find_get_block_slow+0xc2/0x330 fs/buffer.c:212
 [<ffffffff81621b4e>] __find_get_block+0x23e/0x4c0 fs/buffer.c:1360
 [<ffffffff81622959>] __getblk_slow fs/buffer.c:1101 [inline]
 [<ffffffff81622959>] __getblk_gfp+0x189/0x710 fs/buffer.c:1386
 [<ffffffff816262fd>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff817d11f0>] sb_bread_unmovable include/linux/buffer_head.h:306 [inline]
 [<ffffffff817d11f0>] ext4_fill_super+0x3e30/0xb260 fs/ext4/super.c:3892
 [<ffffffff81579d67>] mount_bdev+0x2c7/0x390 fs/super.c:1100
 [<ffffffff817a95e4>] ext4_mount+0x34/0x40 fs/ext4/super.c:5558
 [<ffffffff8157baec>] mount_fs+0x28c/0x370 fs/super.c:1206
 [<ffffffff815db091>] vfs_kern_mount.part.29+0xd1/0x3d0 fs/namespace.c:991
 [<ffffffff815e29b9>] vfs_kern_mount fs/namespace.c:973 [inline]
 [<ffffffff815e29b9>] do_new_mount fs/namespace.c:2513 [inline]
 [<ffffffff815e29b9>] do_mount+0x3c9/0x2740 fs/namespace.c:2835
 [<ffffffff815e570e>] SYSC_mount fs/namespace.c:3051 [inline]
 [<ffffffff815e570e>] SyS_mount+0xfe/0x110 fs/namespace.c:3028
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c