Linux-api Archive mirror
 help / color / mirror / Atom feed
From: Andy Lutomirski <luto@amacapital.net>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Tycho Andersen <tycho@tycho.pizza>,
	Christian Brauner <brauner@kernel.org>,
	linux-kernel@vger.kernel.org,  linux-api@vger.kernel.org,
	Tycho Andersen <tandersen@netflix.com>,
	 "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [RFC PATCH] pidfd: implement PIDFD_THREAD flag for pidfd_open()
Date: Wed, 31 Jan 2024 10:11:55 -0800	[thread overview]
Message-ID: <CALCETrUFDkt+K9zG8mczxzAFy9t-6Mx5Cz-Sx+it6a4nt+O0pg@mail.gmail.com> (raw)
In-Reply-To: <20240129112313.GA11635@redhat.com>

On Mon, Jan 29, 2024 at 3:24 AM Oleg Nesterov <oleg@redhat.com> wrote:
>
> On 01/27, Oleg Nesterov wrote:
> >
> > I'll (hopefully) send v2 on top of
> >
> >       pidfd: cleanup the usage of __pidfd_prepare's flags
> >       pidfd: don't do_notify_pidfd() if !thread_group_empty()
> >
> > on Monday
>
> Sorry, I don't have time to finish v2 today, I need to update the comments
> and write the changelog.
>
> But the patch itself is ready, I am sending it for review.
>
> Tycho, Christian, any comments?

Right now, pidfd_send_signal() sends signals to processes, like so:

 * The syscall currently only signals via PIDTYPE_PID which covers
 * kill(<positive-pid>, <signal>. It does not signal threads or process
 * groups.

This patch adds PIDFD_THREAD which, potentially confusingly, doesn't
change this (AFAICS).  So at least that should be documented loudly
and clearly, IMO.  But I actually just bumped in to this limitation in
pidfd_send_signal(), like so:

https://github.com/systemd/systemd/issues/31093

Specifically, systemd can't properly emulate Ctrl-C using pidfd_send_signal().

I don't know whether implementing the other signal types belongs as
part of this patch, but they're at least thematically related.

--Andy

  parent reply	other threads:[~2024-01-31 18:12 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-23 15:34 [PATCH v3 0/3] pidfds for non thread group leaders Tycho Andersen
2024-01-23 15:34 ` [PATCH v3 1/3] pidfd: allow pidfd_open() on non-thread-group leaders Tycho Andersen
2024-01-23 19:56   ` Oleg Nesterov
2024-01-23 21:10     ` Tycho Andersen
2024-01-23 22:22       ` Oleg Nesterov
2024-01-24  1:25         ` Oleg Nesterov
2024-01-25 14:08       ` Oleg Nesterov
2024-01-25 17:17         ` Christian Brauner
2024-01-25 17:51           ` Oleg Nesterov
2024-01-25 18:03             ` Tycho Andersen
2024-01-25 18:25               ` Oleg Nesterov
2024-01-25 18:30                 ` Oleg Nesterov
2024-01-25 18:36                   ` Tycho Andersen
2024-01-26  9:49                     ` Christian Brauner
2024-01-26  9:42             ` Christian Brauner
2024-01-26 14:33               ` Oleg Nesterov
2024-01-26  9:47         ` Christian Brauner
2024-01-26 14:33           ` Oleg Nesterov
2024-01-27 14:26             ` Christian Brauner
2024-01-26 21:50         ` Tycho Andersen
2024-01-27 10:54           ` Oleg Nesterov
2024-01-27 14:33             ` Christian Brauner
2024-01-27 15:55             ` Tycho Andersen
2024-01-27 16:31               ` Oleg Nesterov
2024-01-27 17:20                 ` Tycho Andersen
2024-01-27 19:31                   ` Oleg Nesterov
2024-01-27 20:44                     ` Tycho Andersen
2024-01-27 21:10                       ` Oleg Nesterov
2024-01-29 11:23                         ` [RFC PATCH] pidfd: implement PIDFD_THREAD flag for pidfd_open() Oleg Nesterov
2024-01-29 13:41                           ` Christian Brauner
2024-01-29 14:31                             ` Tycho Andersen
2024-01-29 15:14                               ` Christian Brauner
2024-01-30 11:21                             ` Oleg Nesterov
2024-01-31 18:11                           ` Andy Lutomirski [this message]
2024-01-31 18:48                             ` Oleg Nesterov
2024-01-31 19:14                               ` Oleg Nesterov
2024-01-31 19:24                                 ` Andy Lutomirski
2024-01-31 19:46                                   ` Christian Brauner
2024-01-31 19:50                                     ` Andy Lutomirski
2024-02-01 13:30                                       ` Christian Brauner
2024-02-01 13:39                                         ` Christian Brauner
2024-02-01 19:33                                           ` Andy Lutomirski
2024-01-23 15:34 ` [PATCH v3 2/3] selftests/pidfd: add non-thread-group leader tests Tycho Andersen
2024-01-23 15:34 ` [PATCH v3 3/3] clone: allow CLONE_THREAD | CLONE_PIDFD together Tycho Andersen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CALCETrUFDkt+K9zG8mczxzAFy9t-6Mx5Cz-Sx+it6a4nt+O0pg@mail.gmail.com \
    --to=luto@amacapital.net \
    --cc=brauner@kernel.org \
    --cc=ebiederm@xmission.com \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=oleg@redhat.com \
    --cc=tandersen@netflix.com \
    --cc=tycho@tycho.pizza \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).