[syzbot] [mm?] kernel BUG in __khugepaged_enter

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1e83ccd5921a sched/mmcid: Don't assume CID is CPU owned on..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1169dae6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=54ae71b284dd0e13
dashboard link: https://syzkaller.appspot.com/bug?extid=6b554d491efbe066b701
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed43f42e3ea1/disk-1e83ccd5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d8af54a32588/vmlinux-1e83ccd5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/34e6a8cc1037/bzImage-1e83ccd5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6b554d...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at mm/khugepaged.c:438!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 16472 Comm: syz.3.2372 Tainted: G U W L XTNJ syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [W]=WARN, [L]=SOFTLOCKUP, [X]=AUX, [T]=RANDSTRUCT, [N]=TEST, [J]=FWCTL
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__khugepaged_enter+0x30a/0x380 mm/khugepaged.c:438
Code: 64 7e 8e e8 a8 dc 66 ff e8 93 e6 8d ff 5b 5d 41 5c 41 5d 41 5e 41 5f e9 04 6c 04 09 e8 7f e6 8d ff 48 89 df e8 17 33 d9 ff 90 <0f> 0b 48 89 ef e8 dc 51 f8 ff e9 3b fd ff ff e8 f2 52 f8 ff e9 e1
RSP: 0018:ffffc9000e98fba8 EFLAGS: 00010292
RAX: 000000000000031f RBX: ffff888079b24980 RCX: 0000000000000000
RDX: 000000000000031f RSI: ffffffff81e5b2c9 RDI: fffff52001d31f1c
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000001 R12: 0000000008100177
R13: ffff88804adf9510 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f06093436c0(0000) GS:ffff8881245b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff341d3f52 CR3: 00000000319b0000 CR4: 00000000003526f0
Call Trace:
<TASK>
khugepaged_enter_vma mm/khugepaged.c:467 [inline]
khugepaged_enter_vma+0x137/0x2c0 mm/khugepaged.c:461
do_huge_pmd_anonymous_page+0x1c8/0x1c00 mm/huge_memory.c:1469
create_huge_pmd mm/memory.c:6102 [inline]
__handle_mm_fault+0x1e96/0x2b50 mm/memory.c:6376
handle_mm_fault+0x36d/0xa20 mm/memory.c:6583
do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x87560
Code: Unable to access opcode bytes at 0x87536.
RSP: 002b:000000000000000e EFLAGS: 00010202
RAX: 0000000000000000 RBX: 00007f0608615fa0 RCX: 00007f060839bf79
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0002000020003b4a
RBP: 00007f06084327e0 R08: 0000000000000103 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0608616038 R14: 00007f0608615fa0 R15: 00007ffee482e7a8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__khugepaged_enter+0x30a/0x380 mm/khugepaged.c:438
Code: 64 7e 8e e8 a8 dc 66 ff e8 93 e6 8d ff 5b 5d 41 5c 41 5d 41 5e 41 5f e9 04 6c 04 09 e8 7f e6 8d ff 48 89 df e8 17 33 d9 ff 90 <0f> 0b 48 89 ef e8 dc 51 f8 ff e9 3b fd ff ff e8 f2 52 f8 ff e9 e1
RSP: 0018:ffffc9000e98fba8 EFLAGS: 00010292
RAX: 000000000000031f RBX: ffff888079b24980 RCX: 0000000000000000
RDX: 000000000000031f RSI: ffffffff81e5b2c9 RDI: fffff52001d31f1c
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000001 R12: 0000000008100177
R13: ffff88804adf9510 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f06093436c0(0000) GS:ffff8881245b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055906703f168 CR3: 00000000319b0000 CR4: 00000000003526f0


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