Re: [PATCH v2 0/6] x86/alternatives: text_poke() fixes

From: Nadav Amit
Date: Thu Sep 06 2018 - 14:38:40 EST


at 11:31 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Thu, Sep 06, 2018 at 11:09:23AM -0700, Andy Lutomirski wrote:
>>> On Sep 6, 2018, at 10:58 AM, Nadav Amit <namit@xxxxxxxxxx> wrote:
>>> It depends what security you want. Some may consider even the short
>>> time-window in which the kernel code is writable from other cores as
>>> insufficient for security.
>>>
>>> In addition, the set removes the need for remote TLB shootdowns that
>>> text_poke() - with this fix - requires.
>>
>> Iâm personally in favor of not needing a global broadcast flush to install kprobes.
>
> That's fine. But at that point its an optimization, not a correctness
> issue.

Note that patch 1/6 is still needed to fix false lockdep shoutouts due to a
recent patch.