Re: [PATCH v2 1/4] mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

From: Michael Ellerman
Date: Tue Sep 15 2020 - 07:33:05 EST


Nicholas Piggin <npiggin@xxxxxxxxx> writes:
> Excerpts from peterz@xxxxxxxxxxxxx's message of September 14, 2020 8:56 pm:
>> On Mon, Sep 14, 2020 at 02:52:16PM +1000, Nicholas Piggin wrote:
>>> Reading and modifying current->mm and current->active_mm and switching
>>> mm should be done with irqs off, to prevent races seeing an intermediate
>>> state.
...
>>>
>>> Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
>>
>> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
>>
>> I'm thinking we want this selected on x86 as well. Andy?
>
> Thanks for the ack. The plan was to take it through the powerpc tree,
> but if you'd want x86 to select it, maybe a topic branch? Although
> Michael will be away during the next merge window so I don't want to
> get too fancy. Would you mind doing it in a follow up merge after
> powerpc, being that it's (I think) a small change?

Or get akpm to take the series, including the x86 change.

cheers