Oops: general protection fault, probably for non-canonical address 0xdffffc0000000084: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000420-0x0000000000000427]
CPU: 1 UID: 0 PID: 47 Comm: khugepaged Not tainted 6.12.0-rc4-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:khugepaged_scan_mm_slot mm/khugepaged.c:2383 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2515 [inline]
RIP: 0010:khugepaged+0xaee/0x15e0 mm/khugepaged.c:2571
Code: 31 ff 41 bc 01 00 00 00 45 31 ed e9 96 fd ff ff e8 57 f6 97 ff 49 8d 7d 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 bf 09 00 00 49 8d 7d 70 49 8b 6d 20 48 b9 00 00
RSP: 0018:ffffc900009f7cd0 EFLAGS: 00010207
RAX: 0000000000000084 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88801ff5a440 RSI: ffffffff81f588a9 RDI: 0000000000000426
RBP: 0000000000001000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000802
R13: 0000000000000406 R14: 0000000020800000 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff88806a700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9cf626d680 CR3: 000000000df7c000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 000000000000000a DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:khugepaged_scan_mm_slot mm/khugepaged.c:2383 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2515 [inline]
RIP: 0010:khugepaged+0xaee/0x15e0 mm/khugepaged.c:2571
Code: 31 ff 41 bc 01 00 00 00 45 31 ed e9 96 fd ff ff e8 57 f6 97 ff 49 8d 7d 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 bf 09 00 00 49 8d 7d 70 49 8b 6d 20 48 b9 00 00
RSP: 0018:ffffc900009f7cd0 EFLAGS: 00010207
RAX: 0000000000000084 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88801ff5a440 RSI: ffffffff81f588a9 RDI: 0000000000000426
RBP: 0000000000001000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000802
R13: 0000000000000406 R14: 0000000020800000 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff88806a600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9cf6441d58 CR3: 000000005db9a000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	31 ff                	xor    %edi,%edi
   2:	41 bc 01 00 00 00    	mov    $0x1,%r12d
   8:	45 31 ed             	xor    %r13d,%r13d
   b:	e9 96 fd ff ff       	jmp    0xfffffda6
  10:	e8 57 f6 97 ff       	call   0xff97f66c
  15:	49 8d 7d 20          	lea    0x20(%r13),%rdi
  19:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  20:	fc ff df
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	0f 85 bf 09 00 00    	jne    0x9f3
  34:	49 8d 7d 70          	lea    0x70(%r13),%rdi
  38:	49 8b 6d 20          	mov    0x20(%r13),%rbp
  3c:	48                   	rex.W
  3d:	b9                   	.byte 0xb9