[syzbot] [mm?] kernel BUG in hpage_collapse_scan_file (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ca3a02fda4da Add linux-next specific files for 20260123
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10c42452580000
kernel config: https://syzkaller.appspot.com/x/.config?x=10f2b64f8f12b9a4
dashboard link: https://syzkaller.appspot.com/bug?extid=bf6e6a6ca143afea5ca2
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17f7cbfa580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=112d405a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/291ebca63a31/disk-ca3a02fd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b2112a214b54/vmlinux-ca3a02fd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/77d1ae437e07/bzImage-ca3a02fd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bf6e6a...@syzkaller.appspotmail.com

node ffff888148816ec0 offset 0 parent ffff888148817700 shift 0 count 64 values 0 array ffff88807be6b0f0 list ffff888148816ed8 ffff888148816ed8 marks 0 0 0
------------[ cut here ]------------
kernel BUG at ./include/linux/xarray.h:1441!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6017 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
RIP: 0010:XAS_INVALID include/linux/xarray.h:1441 [inline]
RIP: 0010:collapse_file mm/khugepaged.c:2041 [inline]
RIP: 0010:hpage_collapse_scan_file+0x4e0c/0x50e0 mm/khugepaged.c:2387
Code: ff 48 89 df 48 c7 c6 c0 8c bc 8b e8 ee 6c f6 fe 90 0f 0b 48 85 db 0f 84 29 01 00 00 e8 bd 34 91 ff 48 89 df e8 f5 c4 4b 09 90 <0f> 0b e8 ad 34 91 ff 48 89 df 48 c7 c6 c0 8c bc 8b e8 be 6c f6 fe
RSP: 0018:ffffc9000422f120 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888148816ec0 RCX: 6c90c8cc739bf400
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000422f428 R08: ffffc9000422eea7 R09: 1ffff92000845dd4
R10: dffffc0000000000 R11: fffff52000845dd5 R12: 00000003fffffffc
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000555592982500(0000) GS:ffff8881256ef000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30363fff CR3: 0000000031994000 CR4: 00000000003526f0
Call Trace:
<TASK>
madvise_collapse+0x42f/0xb30 mm/khugepaged.c:2817
madvise_vma_behavior+0x10ad/0x43f0 mm/madvise.c:1372
madvise_walk_vmas+0x57a/0xaf0 mm/madvise.c:1721
madvise_do_behavior+0x386/0x540 mm/madvise.c:1937
do_madvise+0x1fa/0x2e0 mm/madvise.c:2030
__do_sys_madvise mm/madvise.c:2039 [inline]
__se_sys_madvise mm/madvise.c:2037 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2037
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f948ad9acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd1ef477c8 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f948b015fa0 RCX: 00007f948ad9acb9
RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000200000000000
RBP: 00007f948ae08bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f948b015fac R14: 00007f948b015fa0 R15: 00007f948b015fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:XAS_INVALID include/linux/xarray.h:1441 [inline]
RIP: 0010:collapse_file mm/khugepaged.c:2041 [inline]
RIP: 0010:hpage_collapse_scan_file+0x4e0c/0x50e0 mm/khugepaged.c:2387
Code: ff 48 89 df 48 c7 c6 c0 8c bc 8b e8 ee 6c f6 fe 90 0f 0b 48 85 db 0f 84 29 01 00 00 e8 bd 34 91 ff 48 89 df e8 f5 c4 4b 09 90 <0f> 0b e8 ad 34 91 ff 48 89 df 48 c7 c6 c0 8c bc 8b e8 be 6c f6 fe
RSP: 0018:ffffc9000422f120 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888148816ec0 RCX: 6c90c8cc739bf400
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000422f428 R08: ffffc9000422eea7 R09: 1ffff92000845dd4
R10: dffffc0000000000 R11: fffff52000845dd5 R12: 00000003fffffffc
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000555592982500(0000) GS:ffff8881256ef000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0001002a0 CR3: 0000000031994000 CR4: 00000000003526f0


---
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