IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
INFO: task syz-executor0:15392 blocked for more than 120 seconds.
      Not tainted 4.9.110-g00a0bcb #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D30424 15392   9527 0x00000004
 ffff8801a259c800 ffff8801ad3d8000 ffff8801ad3d8000 ffff8801cb879800
 ffff8801db321c18 ffff8801a1027b08 ffffffff839e6ded ffffffff812355f7
 0000000000000000 ffff8801a259d0c0 0000000600000007 ffff8801db3224e8
Call Trace:
 [<ffffffff839e83ef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f3a28>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff839f3a28>] rwsem_down_write_failed+0x598/0x990 kernel/locking/rwsem-xadd.c:555
 [<ffffffff81ee6607>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
 [<ffffffff839f17fc>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff839f17fc>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
 [<ffffffff8156a6e8>] inode_lock include/linux/fs.h:766 [inline]
 [<ffffffff8156a6e8>] do_truncate2+0x128/0x1f0 fs/open.c:61
 [<ffffffff8156b36e>] do_sys_ftruncate.constprop.16+0x3ce/0x4a0 fs/open.c:213
 [<ffffffff8156b52c>] SYSC_ftruncate fs/open.c:223 [inline]
 [<ffffffff8156b52c>] SyS_ftruncate+0x1c/0x30 fs/open.c:221
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f7cd3>] 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: [<ffffffff8136662c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136662c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425cb7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3724:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f5e92>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211e1e2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor0/15392:
 #0:  (sb_writers#10){.+.+.+}, at: [<ffffffff8156b1aa>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#10){.+.+.+}, at: [<ffffffff8156b1aa>] do_sys_ftruncate.constprop.16+0x20a/0x4a0 fs/open.c:208
 #1:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff8156a6e8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff8156a6e8>] do_truncate2+0x128/0x1f0 fs/open.c:61

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

NMI backtrace for cpu 1
CPU: 1 PID: 520 Comm: khungtaskd Not tainted 4.9.110-g00a0bcb #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8507d08 ffffffff81eb2329 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9580 ffff8801d8507d40
 ffffffff81ebd627 0000000000000001 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81eb2329>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb2329>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebd627>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebd5ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9684>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366bc4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366bc4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366bc4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366bc4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f7e9c>] 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: 15391 Comm: syz-executor0 Not tainted 4.9.110-g00a0bcb #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801be779800 task.stack: ffff8801c4730000
RIP: 0010:[<ffffffff8135e978>] 
c [<ffffffff8135e978>] __sanitizer_cov_trace_pc+0x38/0x50 kernel/kcov.c:106
RSP: 0018:ffff8801c47370f8  EFLAGS: 00000046
RAX: 0000000000040000 RBX: 0000000000000009 RCX: ffffc900004b5000
RDX: 0000000000000002 RSI: ffffffff81624206 RDI: ffff8801c5ee7c90
RBP: ffff8801c47370f8 R08: ffff8801be77a188 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff10037cef42c R12: ffff8801c5ee7c78
R13: dffffc0000000000 R14: ffff8801c5ee7c78 R15: 0000000000000008
FS:  00007f5787c32700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4c2e986000 CR3: 00000001c440a000 CR4: 00000000001606f0
DR0: 00000000200001c0 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff8801c4737148
c ffffffff81624206
c 00000200070fddc0
c 0000000000000041
c
 ffff8801cbfaae00
c 0000000000000001
c ffffea00070fdddc
c ffffea00070fddc0
c
 0000000000000200
c dffffc0000000000
c ffff8801c47371e8
c ffffffff816251e9
c
Call Trace:
 [<ffffffff81624206>] lookup_bh_lru fs/buffer.c:1327 [inline]
 [<ffffffff81624206>] __find_get_block+0x66/0x4c0 fs/buffer.c:1356
 [<ffffffff816251e9>] __getblk_slow fs/buffer.c:1101 [inline]
 [<ffffffff816251e9>] __getblk_gfp+0x189/0x710 fs/buffer.c:1386
 [<ffffffff81628b8d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818c3f4b>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818c3f4b>] fat12_ent_bread+0x13b/0x400 fs/fat/fatent.c:75
 [<ffffffff818c63db>] fat_ent_read_block fs/fat/fatent.c:441 [inline]
 [<ffffffff818c63db>] fat_alloc_clusters+0x51b/0xe10 fs/fat/fatent.c:489
 [<ffffffff818d35af>] fat_add_cluster+0x6f/0xe0 fs/fat/inode.c:100
 [<ffffffff818d38ff>] __fat_get_block fs/fat/inode.c:147 [inline]
 [<ffffffff818d38ff>] fat_get_block+0x2df/0x800 fs/fat/inode.c:176
 [<ffffffff81629dd1>] __block_write_begin_int+0x391/0x1040 fs/buffer.c:1987
 [<ffffffff8162ab1f>] __block_write_begin fs/buffer.c:2038 [inline]
 [<ffffffff8162ab1f>] block_write_begin+0x5f/0x180 fs/buffer.c:2097
 [<ffffffff8162b133>] cont_write_begin+0x4f3/0x810 fs/buffer.c:2450
 [<ffffffff818cfa6a>] fat_write_begin+0x9a/0x120 fs/fat/inode.c:222
 [<ffffffff81435c91>] generic_perform_write+0x301/0x510 mm/filemap.c:2740
 [<ffffffff8143d66a>] __generic_file_write_iter+0x29a/0x540 mm/filemap.c:2833
 [<ffffffff8143dbf0>] generic_file_write_iter+0x2e0/0x610 mm/filemap.c:2893
 [<ffffffff8156eb60>] new_sync_write fs/read_write.c:496 [inline]
 [<ffffffff8156eb60>] __vfs_write+0x3e0/0x580 fs/read_write.c:509
 [<ffffffff81572957>] vfs_write+0x187/0x530 fs/read_write.c:557
 [<ffffffff81576789>] SYSC_write fs/read_write.c:604 [inline]
 [<ffffffff81576789>] SyS_write+0xd9/0x1c0 fs/read_write.c:596
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f7cd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c65 
c8b 
c15 
cfc 
c93 
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 
c<48> 
c8b 
c11 
c48 
c83 
cc2 
c01 
c48 
c39 
cd0 
c76 
c07 
c48 
c89 
c34 
cd1 
c48 
c89 
c11 
c5d 
cc3 
c