------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/signal.c:334 task_participate_group_stop+0x21d/0x2d0 kernel/signal.c:334()
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 1 Comm: init Not tainted 4.4.107-g610c835 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 97cc29f8b0898c29 ffff8801da20fa38 ffffffff81d0457d
 ffffffff838429a0 ffff8801da20fb10 ffffffff838485e0 0000000000000009
 000000000000014e ffff8801da20fb00 ffffffff8141774a 0000000041b58ab3
Call Trace:
 [<ffffffff81d0457d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d0457d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8141774a>] panic+0x1aa/0x388 kernel/panic.c:112
 [<ffffffff8112adb5>] warn_slowpath_common+0x125/0x140 kernel/panic.c:455
 [<ffffffff8112b019>] warn_slowpath_null+0x29/0x30 kernel/panic.c:492
 [<ffffffff811509fd>] task_participate_group_stop+0x21d/0x2d0 kernel/signal.c:334
 [<ffffffff8115527b>] do_signal_stop+0x19b/0x7a0 kernel/signal.c:2022
 [<ffffffff81159d48>] get_signal+0x4c8/0x1660 kernel/signal.c:2278
 [<ffffffff8100e7fb>] do_signal+0x8b/0x1d40 arch/x86/kernel/signal.c:712
 [<ffffffff81003602>] exit_to_usermode_loop+0x122/0x170 arch/x86/entry/common.c:247
 [<ffffffff81006545>] prepare_exit_to_usermode arch/x86/entry/common.c:282 [inline]
 [<ffffffff81006545>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:347
 [<ffffffff83773e9e>] int_ret_from_sys_call+0x25/0x9f
Shutting down cpus with NMI
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..