------------[ cut here ]------------
WARNING: CPU: 1 PID: 4050 at kernel/kthread.c:87 free_kthread_struct+0xa2/0xe0 kernel/kthread.c:87
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4050 Comm: modprobe Not tainted 4.14.0-rc2-mm1+ #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 panic+0x1e4/0x41c kernel/panic.c:181
 __warn+0x1c4/0x1e0 kernel/panic.c:542
 report_bug+0x211/0x2d0 lib/bug.c:183
 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178
 do_trap_no_signal arch/x86/kernel/traps.c:212 [inline]
 do_trap+0x260/0x390 arch/x86/kernel/traps.c:261
 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311
 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
RIP: 0010:free_kthread_struct+0xa2/0xe0 kernel/kthread.c:87
RSP: 0018:ffff8801db307768 EFLAGS: 00010206
RAX: 0000000080000100 RBX: ffff8801c2afeac0 RCX: 1ffff1003b660ee1
RDX: ffff8801c0c16300 RSI: 0000000000000000 RDI: ffff8801c2afec48
RBP: ffff8801db307770 R08: 0000000000000000 R09: 1ffff1003b660ed4
R10: ffff8801c0c16300 R11: 0000000000000003 R12: 1ffff1003b660ef0
R13: 1ffff1003b660ef4 R14: 0000000000000000 R15: ffff8801db3077e0
 free_task+0x134/0x1a0 kernel/fork.c:386
 __put_task_struct+0x229/0x3b0 kernel/fork.c:667
 put_task_struct include/linux/sched/task.h:95 [inline]
 delayed_put_task_struct+0xca/0x3d0 kernel/exit.c:180
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2758 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:3012 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2979 [inline]
 rcu_process_callbacks+0xd74/0x17d0 kernel/rcu/tree.c:2996
 __do_softirq+0x29d/0xbb2 kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364 [inline]
 irq_exit+0x1d3/0x210 kernel/softirq.c:405
 exiting_irq arch/x86/include/asm/apic.h:540 [inline]
 smp_apic_timer_interrupt+0x16b/0x700 arch/x86/kernel/apic/apic.c:1041
 apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:770
 </IRQ>
RIP: 0010:filemap_fault+0x19e/0x1d30 mm/filemap.c:2385
RSP: 0018:ffff8801c15eed58 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff11
RAX: ffff8801c0c52798 RBX: ffff8801c1286630 RCX: 0000000000000000
RDX: ffff8801c0c52798 RSI: ffffffff8130cf2d RDI: ffff8801c12866d0
RBP: ffff8801c15ef218 R08: ffff8801c15eeaf8 R09: ffff8801c15eeaf0
R10: ffff8801c15eea68 R11: 1ffff10038182ef3 R12: ffff8801c15ef490
R13: ffff8801c15ef490 R14: ffff8801c15ef1f0 R15: ffff8801c15ef490
 ext4_filemap_fault+0x85/0xb0 fs/ext4/inode.c:6104
 __do_fault+0xeb/0x30f mm/memory.c:3190
 do_cow_fault mm/memory.c:3629 [inline]
 do_fault mm/memory.c:3702 [inline]
 handle_pte_fault mm/memory.c:3930 [inline]
 __handle_mm_fault+0x1617/0x39c0 mm/memory.c:4054
 handle_mm_fault+0x334/0x8d0 mm/memory.c:4091
 __do_page_fault+0x5bd/0xd60 arch/x86/mm/fault.c:1444
 do_page_fault+0xee/0x720 arch/x86/mm/fault.c:1520
 page_fault+0x22/0x30 arch/x86/entry/entry_64.S:1066
RIP: 0010:__clear_user+0x42/0x70 arch/x86/lib/usercopy_64.c:23
RSP: 0018:ffff8801c15ef910 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000000174 RCX: 0000000000000174
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00005556d229e460
RBP: ffff8801c15ef920 R08: ffff8801c15ef250 R09: 1ffff100382bdef6
R10: ffff8801c0c16300 R11: 0000000000000000 R12: 00005556d229e460
R13: 00007ffffffff000 R14: 00005556d229f000 R15: ffff8801c82c1440
 clear_user+0x79/0xa0 arch/x86/lib/usercopy_64.c:53
 padzero fs/binfmt_elf.c:129 [inline]
 load_elf_binary+0x1e53/0x4d80 fs/binfmt_elf.c:1058
 search_binary_handler+0x142/0x6b0 fs/exec.c:1634
 exec_binprm fs/exec.c:1676 [inline]
 do_execveat_common.isra.31+0x1703/0x21c0 fs/exec.c:1798
 do_execve+0x31/0x40 fs/exec.c:1842
 call_usermodehelper_exec_async+0x457/0x8f0 kernel/umh.c:100
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled