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

[Suren Baghdasaryan]

On Tue, Jul 8, 2025 at 4:15 PM Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> wrote:
>
> * Suren Baghdasaryan <surenb@xxxxxxxxxx> [250708 18:19]:
> > On Tue, Jul 8, 2025 at 10:52 AM syzbot
> > <syzbot+80011ad33eec39e6ce42@xxxxxxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> > >
> > > ================================================
> > > 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.
>
> The last one was against v5 patches, is this v6?

Oh, good point. Let me check that. Thanks!