Re: [syzbot] [mm?] WARNING: lock held when returning to user space in lock_next_vma

[Suren Baghdasaryan <surenb@google.com>]

On Tue, Jul 8, 2025 at 10:52 AM syzbot
<syzbot+80011ad33eec39e6ce42@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    26ffb3d6f02c Add linux-next specific files for 20250704
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1719df70580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=1e4f88512ae53408
> dashboard link: https://syzkaller.appspot.com/bug?extid=80011ad33eec39e6ce42
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1124abd4580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1099df70580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/fd5569903143/disk-26ffb3d6.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/1b0c9505c543/vmlinux-26ffb3d6.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/9d864c72bed1/bzImage-26ffb3d6.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+80011ad33eec39e6ce42@syzkaller.appspotmail.com
>
> ================================================
> WARNING: lock held when returning to user space!
> 6.16.0-rc4-next-20250704-syzkaller #0 Not tainted
> ------------------------------------------------
> syz.0.22/6068 is leaving the kernel with locks still held!
> 1 lock held by syz.0.22/6068:
>  #0: ffff8880792a3588 (vm_lock){++++}-{0:0}, at: lock_next_vma+0x146/0xdc0 mm/mmap_lock.c:220

Hmm. I must be missing an unlock_vma() somewhere but I don't see it
yet. Will try the reproducer.

>
>
> ---
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