linux-kernel - Re: [RFC][PATCH] exec: Freeze the other threads during a multi-threaded exec

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Date:   Tue, 28 Jul 2020 19:41:09 +1000
From:   Aleksa Sarai <cyphar@...har.com>
To:     "Eric W. Biederman" <ebiederm@...ssion.com>
Cc:     linux-kernel@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Kees Cook <keescook@...omium.org>, Pavel Machek <pavel@....cz>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        linux-fsdevel@...r.kernel.org, Oleg Nesterov <oleg@...hat.com>,
        linux-pm@...r.kernel.org
Subject: Re: [RFC][PATCH] exec: Freeze the other threads during a
 multi-threaded exec

On 2020-07-27, Eric W. Biederman <ebiederm@...ssion.com> wrote:
> To the best of my knowledge processes with more than one thread
> calling exec are not common, and as all of the threads will be killed
> by exec there does not appear to be any useful work a thread can
> reliably do during exec.

Every Go program which calls exec (this includes runc, Docker, LXD,
Kubernetes, et al) fills the niche of "multi-threaded program that calls
exec" -- all Go programs are multi-threaded and there's no way of
disabling this. This will most likely cause pretty bad performance
regression for basically all container workloads.

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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