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Date:   Wed, 5 Jul 2023 19:24:49 +0200
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Subject: Re: [PATCH v3 2/2] mm: disable CONFIG_PER_VMA_LOCK until its fixed
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To:     Suren Baghdasaryan <surenb@google.com>
Cc:     akpm@linux-foundation.org, jirislaby@kernel.org,
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From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
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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?

-- 
Cheers,

David / dhildenb