Re: [PATCH v3 2/2] mm: disable CONFIG_PER_VMA_LOCK until its fixed

[Suren Baghdasaryan <surenb@google.com>]

On Wed, Jul 5, 2023 at 11:09 AM Suren Baghdasaryan <surenb@google.com> wrote:
>
> On Wed, Jul 5, 2023 at 10:24 AM David Hildenbrand <david@redhat.com> wrote:
> >
> > On 05.07.23 19:22, Suren Baghdasaryan wrote:
> > > On Wed, Jul 5, 2023 at 10:16 AM David Hildenbrand <david@redhat.com> wrote:
> > >>
> > >> On 05.07.23 19:12, Suren Baghdasaryan wrote:
> > >>> A memory corruption was reported in [1] with bisection pointing to the
> > >>> patch [2] enabling per-VMA locks for x86.
> > >>> Disable per-VMA locks config to prevent this issue while the problem is
> > >>> being investigated. This is expected to be a temporary measure.
> > >>>
> > >>> [1] https://bugzilla.kernel.org/show_bug.cgi?id=217624
> > >>> [2] https://lore.kernel.org/all/20230227173632.3292573-30-surenb@google.com
> > >>>
> > >>> Reported-by: Jiri Slaby <jirislaby@kernel.org>
> > >>> Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/
> > >>> Reported-by: Jacob Young <jacobly.alt@gmail.com>
> > >>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217624
> > >>> Fixes: 0bff0aaea03e ("x86/mm: try VMA lock-based page fault handling first")
> > >>> Cc: stable@vger.kernel.org
> > >>> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> > >>> ---
> > >>>    mm/Kconfig | 3 ++-
> > >>>    1 file changed, 2 insertions(+), 1 deletion(-)
> > >>>
> > >>> diff --git a/mm/Kconfig b/mm/Kconfig
> > >>> index 09130434e30d..0abc6c71dd89 100644
> > >>> --- a/mm/Kconfig
> > >>> +++ b/mm/Kconfig
> > >>> @@ -1224,8 +1224,9 @@ config ARCH_SUPPORTS_PER_VMA_LOCK
> > >>>           def_bool n
> > >>>
> > >>>    config PER_VMA_LOCK
> > >>> -     def_bool y
> > >>> +     bool "Enable per-vma locking during page fault handling."
> > >>>        depends on ARCH_SUPPORTS_PER_VMA_LOCK && MMU && SMP
> > >>> +     depends on BROKEN
> > >>>        help
> > >>>          Allow per-vma locking during page fault handling.
> > >>>
> > >> Do we have any testing results (that don't reveal other issues :) ) for
> > >> patch #1? Not sure if we really want to mark it broken if patch #1 fixes
> > >> the issue.
> > >
> > > I tested the fix using the only reproducer provided in the reports
> > > plus kernel compilation and my fork stress test. All looked good and
> > > stable but I don't know if other reports had the same issue or
> > > something different.
> >
> > Can you point me at the other reports, so I can quickly scan them?
>
> by Jacob Young: https://bugzilla.kernel.org/show_bug.cgi?id=217624
> by Jiri Slaby: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/

From strace in https://lore.kernel.org/all/f7ad7a42-13c8-a486-d0b7-01d5acf01e13@kernel.org/
looks like clone3() was involved, so this seems quite likely to be the
same issue I think.

> by Holger Hoffstätte:
> https://lore.kernel.org/all/b198d649-f4bf-b971-31d0-e8433ec2a34c@applied-asynchrony.com/
> only saying that Firefox started crashing after upgrading to 6.4.1
>
> >
> > --
> > Cheers,
> >
> > David / dhildenb
> >