Message-ID: <744134e8-387e-4429-b878-87161a45113f@lucifer.local>
Date: Mon, 24 Nov 2025 09:53:13 +0000
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: syzbot <syzbot+3e03c904429660114599@...kaller.appspotmail.com>
Cc: Liam.Howlett@...cle.com, akpm@...ux-foundation.org, jannh@...gle.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org, pfalcato@...e.de,
        syzkaller-bugs@...glegroups.com, vbabka@...e.cz
Subject: Re: [syzbot] [mm?] WARNING in vma_modify (2)

On Sat, Nov 22, 2025 at 09:30:29PM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:

Hi, thanks for the report!

>
> HEAD commit:    fe4d0dea039f Add linux-next specific files for 20251119

Hm this is quite far behind!

This is a known issue that has already been fixed in linux-next.

It'll all be rebased so no syz command is going to be too useful here I think!

Cheers, Lorenzo

> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1011b212580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=151bfd5098f42253
> dashboard link: https://syzkaller.appspot.com/bug?extid=3e03c904429660114599
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12ed9658580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11b0f884580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/8ba50fe0f8f3/disk-fe4d0dea.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b6fd6a81a075/vmlinux-fe4d0dea.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/78cb38ef15c3/bzImage-fe4d0dea.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3e03c904429660114599@...kaller.appspotmail.com
>
>     7f6714fc0000-7f6715b1dfff: ffff8880734eea00
>     7f6715b1e000-7f6715b8dfff: 0000000000000000
>     7f6715b8e000-7f6715b91fff: ffff8880734ee8c0
>     7f6715b92000-7f6715b93fff: ffff8880734ee780
>     7f6715b94000-7f6715b95fff: ffff8880734ee640
>     7f6715b96000-7ffdfe1f0fff: 0000000000000000
>     7ffdfe1f1000-7ffdfe211fff: ffff8880734ee500
>     7ffdfe212000-ffffffffffffffff: 0000000000000000
> ------------[ cut here ]------------
> WARNING: mm/vma.c:818 at vma_merge_existing_range mm/vma.c:818 [inline], CPU#1: syz.0.17/6004
> WARNING: mm/vma.c:818 at vma_modify+0x1614/0x1a70 mm/vma.c:1611, CPU#1: syz.0.17/6004
> Modules linked in:
> CPU: 1 UID: 0 PID: 6004 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
> RIP: 0010:vma_merge_existing_range mm/vma.c:818 [inline]
> RIP: 0010:vma_modify+0x1614/0x1a70 mm/vma.c:1611
> Code: 0b 90 e9 c4 ec ff ff e8 ea e5 a8 ff 90 0f 0b 90 e9 04 ec ff ff e8 dc e5 a8 ff 4c 89 f7 48 c7 c6 60 e6 96 8b e8 5d 85 f2 ff 90 <0f> 0b 90 e9 6a ec ff ff e8 bf e5 a8 ff e9 59 ed ff ff e8 b5 e5 a8
> RSP: 0018:ffffc90002ee7ae8 EFLAGS: 00010282
> RAX: ffffffff8b5d946d RBX: 0000200000ffe000 RCX: ffff8880326c3d00
> RDX: 0000000000000000 RSI: ffffffffffffffff RDI: ffffffffffffffff
> RBP: ffffc90002ee7c20 R08: ffffc90002ee7667 R09: 1ffff920005dcecc
> R10: dffffc0000000000 R11: fffff520005dcecd R12: 0000200000ffe000
> R13: dffffc0000000000 R14: ffffc90002ee7c00 R15: 1ffff920005dcf84
> FS:  0000555555b5c500(0000) GS:ffff888125b72000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f1609b292d0 CR3: 0000000073528000 CR4: 00000000003526f0
> Call Trace:
>  <TASK>
>  vma_modify_flags+0x1e8/0x230 mm/vma.c:1652
>  mlock_fixup+0x24b/0x3b0 mm/mlock.c:481
>  apply_vma_lock_flags+0x285/0x390 mm/mlock.c:554
>  __do_sys_munlock mm/mlock.c:691 [inline]
>  __se_sys_munlock+0x150/0x270 mm/mlock.c:680
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f6714d8f749
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffdfe210298 EFLAGS: 00000246 ORIG_RAX: 0000000000000096
> RAX: ffffffffffffffda RBX: 00007f6714fe5fa0 RCX: 00007f6714d8f749
> RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000200000ffd000
> RBP: 00007f6714e13f91 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f6714fe5fa0 R14: 00007f6714fe5fa0 R15: 0000000000000002
>  </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 syzkaller@...glegroups.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

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