From: Andrei Vagin <avagin@gmail.com>
To: Kees Cook <kees@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Christian Brauner <brauner@kernel.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Kees Cook <keescook@chromium.org>, Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Peter Oskolkov <posk@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Tycho Andersen <tycho@tycho.pizza>,
Will Drewry <wad@chromium.org>,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH 1/5] seccomp: don't use semaphore and wait_queue together
Date: Thu, 20 Oct 2022 21:30:03 -0700 [thread overview]
Message-ID: <Y1IgS3w/M1vnEC8D@gmail.com> (raw)
In-Reply-To: <F4707F74-22D4-402B-8FC6-992AEADDFD33@kernel.org>
On Wed, Oct 19, 2022 at 10:10:44PM -0700, Kees Cook wrote:
> On October 19, 2022 6:10:44 PM PDT, Andrei Vagin <avagin@gmail.com> wrote:
> >Here is no reason to use two different primitives that do similar things.
> >
> >Signed-off-by: Andrei Vagin <avagin@gmail.com>
> >---
> > kernel/seccomp.c | 41 ++++++++++++++++++++++++++++++++++++-----
> > 1 file changed, 36 insertions(+), 5 deletions(-)
>
> The commit log does not justify adding 29 lines to "do similar
> things". :) Can you describe the rationale and benefits here a bit
> more? I assume this to use the the future new wake_up helper?
The main reason is to use new wake_up helpers, but there are a few
other reasons:
* if we use two different ways, we always need to call them both. This
patch fixes seccomp_notify_recv where we forgot to call wake_up_poll
in the error path.
* If we use one primitive, we can control how many waiters are woken up
for each request. Our goal is to wake up just one that will handle a
request. Right now, wake_up_poll may wake up one waiter and
up(&match->notif->request) may wake up one more.
I will update the commit message. Thanks!
>
>
> --
> Kees Cook
next prev parent reply other threads:[~2022-10-21 4:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 1:10 [PATCH 0/5 v2] seccomp: add the synchronous mode for seccomp_unotify Andrei Vagin
2022-10-20 1:10 ` [PATCH 1/5] seccomp: don't use semaphore and wait_queue together Andrei Vagin
2022-10-20 5:10 ` Kees Cook
2022-10-21 4:30 ` Andrei Vagin [this message]
2022-10-20 1:10 ` [PATCH 2/5] sched: add WF_CURRENT_CPU and externise ttwu Andrei Vagin
2022-10-20 4:54 ` Kees Cook
2022-10-21 0:48 ` Andrei Vagin
2022-10-20 1:10 ` [PATCH 3/5] sched: add a few helpers to wake up tasks on the current cpu Andrei Vagin
2022-10-20 14:15 ` Peter Zijlstra
2022-10-21 0:44 ` Andrei Vagin
2022-10-27 6:51 ` Andrei Vagin
2022-10-20 1:10 ` [PATCH 4/5] seccomp: add the synchronous mode for seccomp_unotify Andrei Vagin
2022-10-20 1:10 ` [PATCH 5/5] selftest/seccomp: add a new test for the sync mode of seccomp_user_notify Andrei Vagin
2022-10-20 5:04 ` Kees Cook
2022-10-21 0:53 ` Andrei Vagin
-- strict thread matches above, loose matches on Subject: below --
2022-11-11 7:31 [PATCH 0/5 v3] seccomp: add the synchronous mode for seccomp_unotify Andrei Vagin
2022-11-11 7:31 ` [PATCH 1/5] seccomp: don't use semaphore and wait_queue together Andrei Vagin
2023-01-10 21:30 [PATCH 0/5 v3 RESEND] seccomp: add the synchronous mode for seccomp_unotify Andrei Vagin
2023-01-10 21:30 ` [PATCH 1/5] seccomp: don't use semaphore and wait_queue together Andrei Vagin
2023-01-12 14:58 ` Tycho Andersen
2023-01-13 21:51 ` Andrei Vagin
2023-01-16 9:48 ` Peter Zijlstra
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