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From:   Suren Baghdasaryan <surenb@google.com>
Date:   Wed, 5 Jul 2023 11:09:32 -0700
Message-ID: <CAJuCfpGSt-P6NzTDa8HG6tBKac4Y4Rhkiwcz+80x6aTmVCNS1Q@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] mm: disable CONFIG_PER_VMA_LOCK until its fixed
To:     David Hildenbrand <david@redhat.com>
Cc:     akpm@linux-foundation.org, jirislaby@kernel.org,
        jacobly.alt@gmail.com, holger@applied-asynchrony.com,
        hdegoede@redhat.com, michel@lespinasse.org, jglisse@google.com,
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        willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org,
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On Wed, Jul 5, 2023 at 10:24=E2=80=AFAM David Hildenbrand <david@redhat.com=
> wrote:
>
> On 05.07.23 19:22, Suren Baghdasaryan wrote:
> > On Wed, Jul 5, 2023 at 10:16=E2=80=AFAM 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 th=
e
> >>> 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=3D217624
> >>> [2] https://lore.kernel.org/all/20230227173632.3292573-30-surenb@goog=
le.com
> >>>
> >>> Reported-by: Jiri Slaby <jirislaby@kernel.org>
> >>> Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf=
51b@kernel.org/
> >>> Reported-by: Jacob Young <jacobly.alt@gmail.com>
> >>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=3D217624
> >>> 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 :) ) fo=
r
> >> patch #1? Not sure if we really want to mark it broken if patch #1 fix=
es
> >> 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=3D217624
by Jiri Slaby: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cd=
f51b@kernel.org/
by Holger Hoffst=C3=A4tte:
https://lore.kernel.org/all/b198d649-f4bf-b971-31d0-e8433ec2a34c@applied-as=
ynchrony.com/
only saying that Firefox started crashing after upgrading to 6.4.1

>
> --
> Cheers,
>
> David / dhildenb
>