EXT2-fs (loop4): error: fragsize 1048576 != blocksize 1024(not supported yet)
------------[ cut here ]------------
WARNING: CPU: 1 PID: 17 at net/ipv4/af_inet.c:167 inet_sock_destruct+0x598/0x760 net/ipv4/af_inet.c:167
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 17 Comm: ksoftirqd/1 Not tainted 4.9.123-g8dd3fc2 #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d9abfa48 ffffffff81eb9689 ffffffff83c48ac0 00000000ffffffff
 0000000000000000 0000000000000001 00000000000000a7 ffff8801d9abfb08
 ffffffff81423f75 0000000041b58ab3 ffffffff843bb878 ffffffff81423db6
Call Trace:
 [<ffffffff81eb9689>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb9689>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81423f75>] panic+0x1bf/0x3bc kernel/panic.c:179
 [<ffffffff81424261>] __warn.cold.9+0xc1/0x17f kernel/panic.c:542
 [<ffffffff811383bc>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
 [<ffffffff8342c778>] inet_sock_destruct+0x598/0x760 net/ipv4/af_inet.c:167
 [<ffffffff836c5ab9>] l2tp_tunnel_destruct+0x339/0x590 net/l2tp/l2tp_core.c:1329
 [<ffffffff830280f5>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff81289aae>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff81289aae>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff81289aae>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff81289aae>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff81289aae>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff83a08880>] __do_softirq+0x210/0x940 kernel/softirq.c:288
 [<ffffffff8114d320>] run_ksoftirqd+0x30/0x60 kernel/softirq.c:680
 [<ffffffff811aa5a9>] smpboot_thread_fn+0x5c9/0x900 kernel/smpboot.c:163
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01e5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..