BUG: unable to handle kernel NULL pointer dereference at 000000000000001a
PGD 80000001247de067 P4D 80000001247de067 PUD 1247e1067 PMD 0 
Oops: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 8168 Comm: syz-executor3 Not tainted 4.17.0+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__list_add_valid+0x66/0x450 lib/list_debug.c:23
RSP: 0018:ffff88010b46f5d0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000012 RSI: ffff88021fffab48 RDI: ffffea0006407420
RBP: ffff88010b46f638 R08: 000000000010abe0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000012
R13: ffffea0006407420 R14: 000000000000001a R15: ffffffff8b58d000
FS:  0000000002047940(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000001a CR3: 0000000124072000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __list_add include/linux/list.h:60 [inline]
 list_add include/linux/list.h:79 [inline]
 __free_one_page+0x1483/0x1800 mm/page_alloc.c:876
 free_one_page mm/page_alloc.c:1176 [inline]
 __free_pages_ok+0x870/0x1680 mm/page_alloc.c:1260
 __free_pages+0x109/0x240 mm/page_alloc.c:4442
 kmsan_free_page+0x1b6/0x2e0 mm/kmsan/kmsan.c:963
 free_pages_prepare mm/page_alloc.c:996 [inline]
 __free_pages_ok+0x288/0x1680 mm/page_alloc.c:1254
 __free_pages mm/page_alloc.c:4442 [inline]
 free_pages+0x1e7/0x320 mm/page_alloc.c:4452
 _pgd_free arch/x86/mm/pgtable.c:367 [inline]
 pgd_free+0x2b2/0x360 arch/x86/mm/pgtable.c:416
 mm_free_pgd kernel/fork.c:551 [inline]
 __mmdrop+0x139/0x930 kernel/fork.c:599
 mmdrop include/linux/sched/mm.h:49 [inline]
 __mmput+0x550/0x600 kernel/fork.c:972
 mmput+0xab/0xf0 kernel/fork.c:983
 exit_mm+0x6ed/0x7a0 kernel/exit.c:545
 do_exit+0xc12/0x3930 kernel/exit.c:854
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 __do_sys_exit_group+0x21/0x30 kernel/exit.c:981
 __se_sys_exit_group+0x14/0x20 kernel/exit.c:979
 __x64_sys_exit_group+0x4c/0x50 kernel/exit.c:979
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455b29
RSP: 002b:0000000000a3ea98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000030 RCX: 0000000000455b29
RDX: 0000000000000006 RSI: 00000000007304c8 RDI: 0000000000000000
RBP: 0000000000000013 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000a3ea30 R11: 0000000000000246 R12: 0000000000000013
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000001380
Code: 8b 87 90 0c 00 00 48 89 45 c8 49 8b 47 10 41 8b 8f 98 0c 00 00 48 89 4d b8 4d 8d 74 24 08 48 89 45 d0 48 85 c0 0f 85 33 01 00 00 <4d> 8b 2e 4c 89 f7 e8 9f 96 be fd 4c 8b 30 8b 32 4c 89 f0 48 09 
RIP: __list_add_valid+0x66/0x450 lib/list_debug.c:23 RSP: ffff88010b46f5d0
CR2: 000000000000001a
---[ end trace 73609655df3b1e07 ]---