BUG: unable to handle kernel NULL pointer dereference at 0000000000000205
PGD 800000013d642067 P4D 800000013d642067 PUD 13d645067 PMD 0 
Oops: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4586 Comm: syz-executor4 Not tainted 4.17.0-rc5+ #102
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: 0000:ffff88013d00f610 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000000001fd RSI: ffff88021fffab48 RDI: ffffea00075aa1e0
RBP: ffff88013d00f678 R08: 0000000000139c58 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 00000000000001fd
R13: ffffea00075aa1e0 R14: 0000000000000205 R15: ffffffff8b58b000
FS:  0000000001042940(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000205 CR3: 000000013d78e000 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+0x87f/0x16c0 mm/page_alloc.c:1260
 __free_pages+0x109/0x240 mm/page_alloc.c:4442
 kmsan_free_page+0x197/0x2e0 mm/kmsan/kmsan.c:955
 free_pages_prepare mm/page_alloc.c:996 [inline]
 __free_pages_ok+0x270/0x16c0 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+0xc2/0xd0 include/linux/sched/mm.h:49
 finish_task_switch+0x103/0x270 kernel/sched/core.c:2726
 context_switch kernel/sched/core.c:2866 [inline]
 __schedule+0x688/0x730 kernel/sched/core.c:3507
 schedule+0x1cc/0x2f0 kernel/sched/core.c:3551
 freezable_schedule include/linux/freezer.h:172 [inline]
 do_nanosleep+0x2c3/0x9b0 kernel/time/hrtimer.c:1689
 hrtimer_nanosleep kernel/time/hrtimer.c:1743 [inline]
 __do_sys_nanosleep kernel/time/hrtimer.c:1775 [inline]
 __se_sys_nanosleep+0x4b3/0x6a0 kernel/time/hrtimer.c:1762
 __x64_sys_nanosleep+0x92/0xc0 kernel/time/hrtimer.c:1762
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x481110
RSP: 002b:0000000000a3ea98 EFLAGS: 00000246 ORIG_RAX: 0000000000000023
RAX: ffffffffffffffda RBX: 0000000000000020 RCX: 0000000000481110
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000a3eaa0
RBP: 000000000001d185 R08: 0000000000000001 R09: 0000000001042940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000f R14: 0000000000000169 R15: 000000000001d15c
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 df a3 bf fd 4c 8b 30 8b 32 4c 89 f0 48 09 
RIP: __list_add_valid+0x66/0x450 lib/list_debug.c:23 RSP: ffff88013d00f610
CR2: 0000000000000205
---[ end trace 8bfb8fc0c1149fe3 ]---