[syzbot] [kvm?] WARNING in kvm_gmem_fault_user_mapping

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1f97d9dcf536 Merge tag 'vfio-v6.19-rc8' of https://github...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10b3e322580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f1fac0919970b671
dashboard link: https://syzkaller.appspot.com/bug?extid=33a04338019ac7e43a44
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15e5ebfa580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13eef85a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f898291c4b7b/disk-1f97d9dc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cac48e20323c/vmlinux-1f97d9dc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d2e60d34b7e7/bzImage-1f97d9dc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+33a043...@syzkaller.appspotmail.com

------------[ cut here ]------------
folio_test_large(folio)
WARNING: arch/x86/kvm/../../../virt/kvm/guest_memfd.c:416 at kvm_gmem_fault_user_mapping+0x4b5/0x6e0 virt/kvm/guest_memfd.c:416, CPU#1: syz.3.124/6406
Modules linked in:
CPU: 1 UID: 0 PID: 6406 Comm: syz.3.124 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
RIP: 0010:kvm_gmem_fault_user_mapping+0x4b5/0x6e0 virt/kvm/guest_memfd.c:416
Code: 00 e9 a1 fe ff ff bd 00 04 00 00 eb d9 e8 43 b8 83 00 48 c7 c6 e0 9f 82 8b 48 89 df e8 d4 f8 ce 00 90 0f 0b e8 2c b8 83 00 90 <0f> 0b 90 48 8d 6b 34 48 89 df e8 ec f6 bb 00 be 04 00 00 00 48 89
RSP: 0018:ffffc90004ab7848 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffea00018a0000 RCX: ffffffff81834070
RDX: ffff888028b124c0 RSI: ffffffff81834334 RDI: ffff888028b124c0
RBP: ffffc90004ab79f8 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000040 R11: 0000000000000000 R12: ffffea00018a0000
R13: ffffc90004ab7a08 R14: 0000000000000040 R15: ffffea00018a0008
FS: 00007fb8562ce6c0(0000) GS:ffff8881246db000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f89fb863d58 CR3: 000000006060a000 CR4: 00000000003526f0
Call Trace:
<TASK>
__do_fault+0x10d/0x550 mm/memory.c:5323
do_read_fault mm/memory.c:5758 [inline]
do_fault+0xaf9/0x1990 mm/memory.c:5892
do_pte_missing mm/memory.c:4404 [inline]
handle_pte_fault mm/memory.c:6276 [inline]
__handle_mm_fault+0x1807/0x2b50 mm/memory.c:6414
handle_mm_fault+0x36d/0xa20 mm/memory.c:6583
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0xf9c/0x34d0 mm/gup.c:1428
populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860
__mm_populate+0x107/0x3a0 mm/gup.c:1963
do_mlock+0x3f0/0x7f0 mm/mlock.c:653
__do_sys_mlock mm/mlock.c:661 [inline]
__se_sys_mlock mm/mlock.c:659 [inline]
__x64_sys_mlock+0x59/0x80 mm/mlock.c:659
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb85539aeb9
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:00007fb8562ce028 EFLAGS: 00000246 ORIG_RAX: 0000000000000095
RAX: ffffffffffffffda RBX: 00007fb855615fa0 RCX: 00007fb85539aeb9
RDX: 0000000000000000 RSI: 0000000000800000 RDI: 0000200000000000
RBP: 00007fb855408c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb855616038 R14: 00007fb855615fa0 R15: 00007ffcc1750088
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup