[syzbot] [mm?] WARNING in vma_set_pgoff

Hello,

syzbot found the following issue on:

HEAD commit:    4477a78374a5 Add linux-next specific files for 20260814
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=137fc679580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9b32a36dd637b06f
dashboard link: https://syzkaller.appspot.com/bug?extid=f12658786a4153df5113
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=176d5949580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/994c1c8c560e/disk-4477a783.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cd54543d69ae/vmlinux-4477a783.xz
kernel image: https://storage.googleapis.com/syzbot-assets/407cdf8f3fc2/bzImage-4477a783.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

------------[ cut here ]------------
pgoff != vma->vm_start >> 12
WARNING: mm/vma.h:277 at assert_sane_pgoff mm/vma.h:277 [inline], CPU#1: syz.0.17/5809
WARNING: mm/vma.h:277 at vma_set_pgoff+0x246/0x2d0 mm/vma.h:283, CPU#1: syz.0.17/5809
Modules linked in:
CPU: 1 UID: 0 PID: 5809 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:assert_sane_pgoff mm/vma.h:277 [inline]
RIP: 0010:vma_set_pgoff+0x246/0x2d0 mm/vma.h:283
Code: 0b 90 e9 d5 fe ff ff e8 a8 ed a0 ff 4c 89 f7 e8 50 5b 01 ff c6 05 b6 05 3c 0e 01 90 0f 0b 90 e9 fe fe ff ff e8 8b ed a0 ff 90 <0f> 0b 90 eb 9d 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c eb fd ff ff
RSP: 0018:ffffc900035ef748 EFLAGS: 00010293
RAX: ffffffff8226cfa5 RBX: 0000000200000a98 RCX: ffff88802733ddc0
RDX: 0000000000000000 RSI: 0000000200000002 RDI: 0000000200000a98
RBP: 0000000000000007 R08: ffff888076188bc3 R09: 1ffff1100ec31178
R10: dffffc0000000000 R11: ffffed100ec31179 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888076188b40 R15: 0000000200000002
FS:  0000555576422500(0000) GS:ffff888124df8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9f85a70000 CR3: 000000007cdfc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vma_add_pgoff+0x1a8/0x570 mm/vma.h:314
 __split_vma+0x89e/0xa60 mm/vma.c:607
 vms_gather_munmap_vmas+0x322/0x1370 mm/vma.c:1507
 do_vmi_align_munmap+0x2b4/0x4b0 mm/vma.c:1675
 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1732
 __vm_munmap+0x241/0x3e0 mm/vma.c:3390
 __do_sys_munmap mm/mmap.c:1094 [inline]
 __se_sys_munmap mm/mmap.c:1091 [inline]
 __x64_sys_munmap+0x60/0x70 mm/mmap.c:1091
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9f85b9e0d9
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:00007fff50d2f8f8 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 00007f9f85e25fa0 RCX: 00007f9f85b9e0d9
RDX: 0000000000000000 RSI: 0000000000004000 RDI: 0000200000002000
RBP: 00007f9f85c35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9f85e25fac R14: 00007f9f85e25fa0 R15: 00007f9f85e25fa0
 </TASK>


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