[syzbot] [mm?] general protection fault in khugepaged (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    528dd46d0fc3 Merge tag 'net-6.10-rc8-2' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14f9d0f1980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=38e374b1a3185897
dashboard link: https://syzkaller.appspot.com/bug?extid=33287c327c3bcd4ea552
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/01b3c6d9bec7/disk-528dd46d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7db1f2513396/vmlinux-528dd46d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cfae1c808981/bzImage-528dd46d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+33287c327c3bcd4ea552@xxxxxxxxxxxxxxxxxxxxxxxxx

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 PID: 37 Comm: khugepaged Not tainted 6.10.0-rc7-syzkaller-00254-g528dd46d0fc3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:khugepaged_scan_mm_slot mm/khugepaged.c:2365 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2498 [inline]
RIP: 0010:khugepaged+0x8ec/0x1820 mm/khugepaged.c:2554
Code: e8 39 6d 9d ff 83 44 24 14 01 e9 9b f8 ff ff e8 2a 6d 9d ff 49 8d 7c 24 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 ad 0d 00 00 49 8d 7c 24 70 49 8b 6c 24 20 48 b9
RSP: 0018:ffffc90000ad7ce8 EFLAGS: 00010217
RAX: 0000000000000084 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88801bae9e00 RSI: ffffffff81f1c0f6 RDI: 0000000000000426
RBP: 0000000028100077 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000406
R13: 0000000000000200 R14: 1ffff9200015afaf R15: 0000000000000007
FS:  0000000000000000(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020027000 CR3: 000000006a590000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 kthread+0x2c4/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x48/0x80 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:2365 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2498 [inline]
RIP: 0010:khugepaged+0x8ec/0x1820 mm/khugepaged.c:2554
Code: e8 39 6d 9d ff 83 44 24 14 01 e9 9b f8 ff ff e8 2a 6d 9d ff 49 8d 7c 24 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 ad 0d 00 00 49 8d 7c 24 70 49 8b 6c 24 20 48 b9
RSP: 0018:ffffc90000ad7ce8 EFLAGS: 00010217
RAX: 0000000000000084 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88801bae9e00 RSI: ffffffff81f1c0f6 RDI: 0000000000000426
RBP: 0000000028100077 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000406
R13: 0000000000000200 R14: 1ffff9200015afaf R15: 0000000000000007
FS:  0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2eb1cff8 CR3: 000000001fc08000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	e8 39 6d 9d ff       	call   0xff9d6d3e
   5:	83 44 24 14 01       	addl   $0x1,0x14(%rsp)
   a:	e9 9b f8 ff ff       	jmp    0xfffff8aa
   f:	e8 2a 6d 9d ff       	call   0xff9d6d3e
  14:	49 8d 7c 24 20       	lea    0x20(%r12),%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 ad 0d 00 00    	jne    0xde1
  34:	49 8d 7c 24 70       	lea    0x70(%r12),%rdi
  39:	49 8b 6c 24 20       	mov    0x20(%r12),%rbp
  3e:	48                   	rex.W
  3f:	b9                   	.byte 0xb9


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