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From:   Suren Baghdasaryan <surenb@google.com>
Date:   Wed, 5 Jul 2023 11:14:51 -0700
Message-ID: <CAJuCfpHdw0rMfuYhAEAp_LC3sMUsBDmaKD_NU9hX8z5TH-CBxw@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,
        mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org,
        mgorman@techsingularity.net, dave@stgolabs.net,
        willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org,
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On Wed, Jul 5, 2023 at 11:09=E2=80=AFAM Suren Baghdasaryan <surenb@google.c=
om> wrote:
>
> On Wed, Jul 5, 2023 at 10:24=E2=80=AFAM David Hildenbrand <david@redhat.c=
om> wrote:
> >
> > On 05.07.23 19:22, Suren Baghdasaryan wrote:
> > > On Wed, Jul 5, 2023 at 10:16=E2=80=AFAM David Hildenbrand <david@redh=
at.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 proble=
m 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@go=
ogle.com
> > >>>
> > >>> Reported-by: Jiri Slaby <jirislaby@kernel.org>
> > >>> Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3c=
df51b@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 handlin=
g 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 f=
ixes
> > >> 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-e9c6e3=
cdf51b@kernel.org/

From strace in https://lore.kernel.org/all/f7ad7a42-13c8-a486-d0b7-01d5acf0=
1e13@kernel.org/
looks like clone3() was involved, so this seems quite likely to be the
same issue I think.

> by Holger Hoffst=C3=A4tte:
> 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
> >