BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0
PGD 80000000a848f067 P4D 80000000a848f067 PUD a848c067 PMD 0 
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 25682 Comm: syz-executor1 Not tainted 4.18.0-rc5+ #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:slab_equal_or_root mm/slab.h:228 [inline]
RIP: 0010:cache_from_obj mm/slab.h:374 [inline]
RIP: 0010:kmem_cache_free+0x319/0x2c30 mm/slub.c:2989
Code: 48 f7 d0 48 21 c8 0f 84 6e 01 00 00 49 39 dc 0f 84 7f 01 00 00 44 89 7d 80 49 8d 9c 24 d0 00 00 00 4d 85 f6 0f 85 c6 11 00 00 <4c> 8b 2b 48 89 df e8 3c 81 03 00 48 8b 00 48 0b 45 a0 74 16 4c 89 
RSP: 0018:ffff8800bacdf698 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000000d0 RCX: 0000000000000000
RDX: ffffffff8ba11000 RSI: 0000000000000001 RDI: ffffea0006000018
RBP: ffff8800bacdf7f0 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000002 R11: ffffffff82079a10 R12: 0000000000000000
R13: 000077ff80000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f18b90b0700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000d0 CR3: 00000000a85ae000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 proc_reg_open+0x3b0/0x860 fs/proc/inode.c:378
 do_dentry_open+0xccc/0x1440 fs/open.c:794
 vfs_open+0x1b6/0x2f0 fs/open.c:908
 do_last fs/namei.c:3399 [inline]
 path_openat+0x49c0/0x69c0 fs/namei.c:3540
 do_filp_open+0x2c1/0x740 fs/namei.c:3574
 do_sys_open+0x643/0x990 fs/open.c:1101
 __do_sys_open fs/open.c:1119 [inline]
 __se_sys_open fs/open.c:1114 [inline]
 __x64_sys_open+0xf2/0x130 fs/open.c:1114
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x40fd11
Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 b4 17 00 00 c3 48 83 ec 08 e8 8a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 d3 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01 
RSP: 002b:00007f18b90afbb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f18b90b06d4 RCX: 000000000040fd11
RDX: 00007f18b90afbe7 RSI: 0000000000000002 RDI: 00007f18b90afbd0
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000017
R10: 000000000000000c R11: 0000000000000293 R12: 00000000ffffffff
R13: 00000000004c262f R14: 00000000004d4170 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
CR2: 00000000000000d0
---[ end trace 6bef9a6fce908b39 ]---
RIP: 0010:slab_equal_or_root mm/slab.h:228 [inline]
RIP: 0010:cache_from_obj mm/slab.h:374 [inline]
RIP: 0010:kmem_cache_free+0x319/0x2c30 mm/slub.c:2989
Code: 48 f7 d0 48 21 c8 0f 84 6e 01 00 00 49 39 dc 0f 84 7f 01 00 00 44 89 7d 80 49 8d 9c 24 d0 00 00 00 4d 85 f6 0f 85 c6 11 00 00 <4c> 8b 2b 48 89 df e8 3c 81 03 00 48 8b 00 48 0b 45 a0 74 16 4c 89 
RSP: 0018:ffff8800bacdf698 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000000d0 RCX: 0000000000000000
RDX: ffffffff8ba11000 RSI: 0000000000000001 RDI: ffffea0006000018
RBP: ffff8800bacdf7f0 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000002 R11: ffffffff82079a10 R12: 0000000000000000
R13: 000077ff80000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f18b90b0700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000d0 CR3: 00000000a85ae000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600