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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 021533194476 Kconfig: Disable -Wstringop-overflow for GCC ..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14acf5b0180000
kernel config: https://syzkaller.appspot.com/x/.config?x=b60b985eda147877
dashboard link: https://syzkaller.appspot.com/bug?extid=45f744a1e9371de016b0
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3d076fc4bbcb/disk-02153319.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/90a9389ef418/vmlinux-02153319.xz
kernel image: https://storage.googleapis.com/syzbot-assets/72fe9fbafdc0/bzImage-02153319.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+45f744...@syzkaller.appspotmail.com

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: 36 Comm: khugepaged Not tainted 6.8.0-rc2-syzkaller-00199-g021533194476 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:khugepaged_scan_mm_slot mm/khugepaged.c:2375 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2508 [inline]
RIP: 0010:khugepaged+0x5bf/0x1620 mm/khugepaged.c:2564
Code: 00 89 de e8 e3 02 a0 ff 85 db 0f 84 68 0d 00 00 e8 f6 07 a0 ff 49 8d 7e 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 21 0f 00 00 49 8d 7e 78 49 8b 6e 20 48 b9 00 00
RSP: 0018:ffffc90000acfcf8 EFLAGS: 00010217
RAX: 0000000000000084 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffff88801b6c8000 RSI: ffffffff81ec61ca RDI: 0000000000000426
RBP: 0000000020000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: 0000000020400000
R13: 0000000000000003 R14: 0000000000000406 R15: 1ffff92000159faf
FS: 0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcb49ad56c6 CR3: 000000004c8d0000 CR4: 0000000000350ef0
Call Trace:
<TASK>
kthread+0x2c9/0x3b0 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:khugepaged_scan_mm_slot mm/khugepaged.c:2375 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2508 [inline]
RIP: 0010:khugepaged+0x5bf/0x1620 mm/khugepaged.c:2564
Code: 00 89 de e8 e3 02 a0 ff 85 db 0f 84 68 0d 00 00 e8 f6 07 a0 ff 49 8d 7e 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 21 0f 00 00 49 8d 7e 78 49 8b 6e 20 48 b9 00 00
RSP: 0018:ffffc90000acfcf8 EFLAGS: 00010217
RAX: 0000000000000084 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffff88801b6c8000 RSI: ffffffff81ec61ca RDI: 0000000000000426
RBP: 0000000020000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: 0000000020400000
R13: 0000000000000003 R14: 0000000000000406 R15: 1ffff92000159faf
FS: 0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a414b4440 CR3: 000000002d3ae000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
0: 00 89 de e8 e3 02 add %cl,0x2e3e8de(%rcx)
6: a0 ff 85 db 0f 84 68 movabs 0xd68840fdb85ff,%al
d: 0d 00
f: 00 e8 add %ch,%al
11: f6 07 a0 testb $0xa0,(%rdi)
14: ff 49 8d decl -0x73(%rcx)
17: 7e 20 jle 0x39
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 21 0f 00 00 jne 0xf55
34: 49 8d 7e 78 lea 0x78(%r14),%rdi
38: 49 8b 6e 20 mov 0x20(%r14),%rbp
3c: 48 rex.W
3d: b9 .byte 0xb9


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