From: Linus Torvalds <torvalds@linux-foundation.org>
To: Daniel Colascione <dancol@google.com>
Cc: Jonathan Kowalski <bl0pbl33p@gmail.com>,
Aleksa Sarai <cyphar@cyphar.com>,
Andy Lutomirski <luto@amacapital.net>,
Christian Brauner <christian@brauner.io>,
Jann Horn <jannh@google.com>, Andrew Lutomirski <luto@kernel.org>,
David Howells <dhowells@redhat.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
Linux API <linux-api@vger.kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
Kees Cook <keescook@chromium.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Michael Kerrisk-manpages <mtk.manpages@gmail.com>,
"Dmitry V. Levin" <ldv@altlinux.org>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH v2 0/5] pid: add pidfd_open()
Date: Mon, 1 Apr 2019 10:32:41 -0700 [thread overview]
Message-ID: <CAHk-=wgXsK1X=PUaHNT9V-h+v2maB1bLA0P3XHXBNRa0e299XQ@mail.gmail.com> (raw)
In-Reply-To: <CAKOZuet2QCoW1XMpTAzXS868PhF-gh14czFn4gwE4A=oX=Yr8w@mail.gmail.com>
On Mon, Apr 1, 2019 at 9:45 AM Daniel Colascione <dancol@google.com> wrote:
>
> But doesn't the CSIGNAL approach still require that libraries somehow
> coordinate which non-SIGCHLD signal they use?
Yes. As mentioned, this was seldom used.
In some cases it's ok, eg aio would just specify the signal in
sigev_signo (except it was never fleshed out to have sival_ptr etc
because nobody ever did it, afaik).
> (Signal coordination a separate problem, unfortunately.)
Yeah, in several cases you would just want to signal a handler
directly, not an index into handlers.
Anyway, I'm just saying that the whole "reap children" part is not
necessarily tied to the pidfd thing. And honestly, nobody ever does
anything like that anyway in practice, because of all the other issues
it causes that you'll hit.
Linus
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Daniel Colascione <dancol@google.com>
Cc: Jonathan Kowalski <bl0pbl33p@gmail.com>,
Aleksa Sarai <cyphar@cyphar.com>,
Andy Lutomirski <luto@amacapital.net>,
Christian Brauner <christian@brauner.io>,
Jann Horn <jannh@google.com>, Andrew Lutomirski <luto@kernel.org>,
David Howells <dhowells@redhat.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
Linux API <linux-api@vger.kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
Kees Cook <keescook@chromium.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Michael Kerrisk-manpages <mtk.manpages@gmail.com>,
"Dmitry V. Levin" <ldv@altlinux.org>,
Andrew Morton <akpm@linux-fou>
Subject: Re: [PATCH v2 0/5] pid: add pidfd_open()
Date: Mon, 1 Apr 2019 10:32:41 -0700 [thread overview]
Message-ID: <CAHk-=wgXsK1X=PUaHNT9V-h+v2maB1bLA0P3XHXBNRa0e299XQ@mail.gmail.com> (raw)
In-Reply-To: <CAKOZuet2QCoW1XMpTAzXS868PhF-gh14czFn4gwE4A=oX=Yr8w@mail.gmail.com>
On Mon, Apr 1, 2019 at 9:45 AM Daniel Colascione <dancol@google.com> wrote:
>
> But doesn't the CSIGNAL approach still require that libraries somehow
> coordinate which non-SIGCHLD signal they use?
Yes. As mentioned, this was seldom used.
In some cases it's ok, eg aio would just specify the signal in
sigev_signo (except it was never fleshed out to have sival_ptr etc
because nobody ever did it, afaik).
> (Signal coordination a separate problem, unfortunately.)
Yeah, in several cases you would just want to signal a handler
directly, not an index into handlers.
Anyway, I'm just saying that the whole "reap children" part is not
necessarily tied to the pidfd thing. And honestly, nobody ever does
anything like that anyway in practice, because of all the other issues
it causes that you'll hit.
Linus
next prev parent reply other threads:[~2019-04-01 17:46 UTC|newest]
Thread overview: 158+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-29 15:54 [PATCH v2 0/5] pid: add pidfd_open() Christian Brauner
2019-03-29 15:54 ` [PATCH v2 1/5] Make anon_inodes unconditional Christian Brauner
2019-03-29 15:54 ` [PATCH v2 2/5] pid: add pidfd_open() Christian Brauner
2019-03-29 23:45 ` Jann Horn
2019-03-29 23:45 ` Jann Horn
2019-03-29 23:55 ` Christian Brauner
2019-03-29 23:55 ` Christian Brauner
2019-03-30 11:53 ` Jürg Billeter
2019-03-30 14:37 ` Christian Brauner
2019-03-30 14:51 ` Jonathan Kowalski
2019-03-30 14:51 ` Jonathan Kowalski
2019-03-29 15:54 ` [PATCH v2 3/5] signal: support pidfd_open() with pidfd_send_signal() Christian Brauner
2019-03-29 15:54 ` [PATCH v2 4/5] signal: PIDFD_SIGNAL_TID threads via pidfds Christian Brauner
2019-03-30 1:06 ` Jann Horn
2019-03-30 1:06 ` Jann Horn
2019-03-30 1:22 ` Christian Brauner
2019-03-30 1:22 ` Christian Brauner
2019-03-30 1:34 ` Christian Brauner
2019-03-30 1:34 ` Christian Brauner
2019-03-30 1:42 ` Christian Brauner
2019-03-30 1:42 ` Christian Brauner
2019-03-29 15:54 ` [PATCH v2 5/5] tests: add pidfd_open() tests Christian Brauner
2019-03-30 16:09 ` [PATCH v2 0/5] pid: add pidfd_open() Linus Torvalds
2019-03-30 16:09 ` Linus Torvalds
2019-03-30 16:11 ` Daniel Colascione
2019-03-30 16:11 ` Daniel Colascione
2019-03-30 16:16 ` Linus Torvalds
2019-03-30 16:16 ` Linus Torvalds
2019-03-30 16:18 ` Linus Torvalds
2019-03-30 16:18 ` Linus Torvalds
2019-03-31 1:07 ` Joel Fernandes
2019-03-31 1:07 ` Joel Fernandes
2019-03-31 2:34 ` Jann Horn
2019-03-31 2:34 ` Jann Horn
2019-03-31 4:08 ` Joel Fernandes
2019-03-31 4:08 ` Joel Fernandes
2019-03-31 4:46 ` Jann Horn
2019-03-31 4:46 ` Jann Horn
2019-03-31 14:52 ` Linus Torvalds
2019-03-31 14:52 ` Linus Torvalds
2019-03-31 15:05 ` Christian Brauner
2019-03-31 15:05 ` Christian Brauner
2019-03-31 15:21 ` Daniel Colascione
2019-03-31 15:21 ` Daniel Colascione
2019-03-31 15:33 ` Jonathan Kowalski
2019-03-31 15:33 ` Jonathan Kowalski
2019-03-30 16:19 ` Christian Brauner
2019-03-30 16:19 ` Christian Brauner
2019-03-30 16:24 ` Linus Torvalds
2019-03-30 16:24 ` Linus Torvalds
2019-03-30 16:34 ` Daniel Colascione
2019-03-30 16:34 ` Daniel Colascione
2019-03-30 16:38 ` Christian Brauner
2019-03-30 16:38 ` Christian Brauner
2019-03-30 17:04 ` Linus Torvalds
2019-03-30 17:04 ` Linus Torvalds
2019-03-30 17:12 ` Christian Brauner
2019-03-30 17:12 ` Christian Brauner
2019-03-30 17:24 ` Linus Torvalds
2019-03-30 17:24 ` Linus Torvalds
2019-03-30 17:37 ` Christian Brauner
2019-03-30 17:37 ` Christian Brauner
2019-03-30 17:50 ` Jonathan Kowalski
2019-03-30 17:50 ` Jonathan Kowalski
2019-03-30 17:52 ` Christian Brauner
2019-03-30 17:52 ` Christian Brauner
2019-03-30 17:59 ` Jonathan Kowalski
2019-03-30 17:59 ` Jonathan Kowalski
2019-03-30 18:02 ` Christian Brauner
2019-03-30 18:02 ` Christian Brauner
2019-03-30 18:00 ` Jann Horn
2019-03-30 18:00 ` Jann Horn
2019-03-31 20:09 ` Andy Lutomirski
2019-03-31 20:09 ` Andy Lutomirski
2019-03-31 21:03 ` Linus Torvalds
2019-03-31 21:03 ` Linus Torvalds
2019-03-31 21:10 ` Christian Brauner
2019-03-31 21:10 ` Christian Brauner
2019-03-31 21:17 ` Linus Torvalds
2019-03-31 21:17 ` Linus Torvalds
2019-03-31 22:03 ` Christian Brauner
2019-03-31 22:03 ` Christian Brauner
2019-03-31 22:16 ` Linus Torvalds
2019-03-31 22:16 ` Linus Torvalds
2019-03-31 22:33 ` Christian Brauner
2019-03-31 22:33 ` Christian Brauner
2019-04-01 0:52 ` Jann Horn
2019-04-01 0:52 ` Jann Horn
2019-04-01 8:47 ` Yann Droneaud
2019-04-01 8:47 ` Yann Droneaud
2019-04-01 10:03 ` Jonathan Kowalski
2019-04-01 10:03 ` Jonathan Kowalski
2019-03-31 23:40 ` Linus Torvalds
2019-03-31 23:40 ` Linus Torvalds
2019-04-01 0:09 ` Al Viro
2019-04-01 0:09 ` Al Viro
2019-04-01 0:18 ` Linus Torvalds
2019-04-01 0:18 ` Linus Torvalds
2019-04-01 0:21 ` Christian Brauner
2019-04-01 0:21 ` Christian Brauner
2019-04-01 6:37 ` Al Viro
2019-04-01 6:37 ` Al Viro
2019-04-01 6:41 ` Al Viro
2019-04-01 6:41 ` Al Viro
2019-03-31 22:03 ` Jonathan Kowalski
2019-03-31 22:03 ` Jonathan Kowalski
2019-04-01 2:13 ` Andy Lutomirski
2019-04-01 2:13 ` Andy Lutomirski
2019-04-01 11:40 ` Aleksa Sarai
2019-04-01 11:40 ` Aleksa Sarai
2019-04-01 15:36 ` Linus Torvalds
2019-04-01 15:36 ` Linus Torvalds
2019-04-01 15:47 ` Christian Brauner
2019-04-01 15:47 ` Christian Brauner
2019-04-01 15:55 ` Daniel Colascione
2019-04-01 15:55 ` Daniel Colascione
2019-04-01 16:01 ` Linus Torvalds
2019-04-01 16:01 ` Linus Torvalds
2019-04-01 16:13 ` Daniel Colascione
2019-04-01 16:13 ` Daniel Colascione
2019-04-01 19:42 ` Christian Brauner
2019-04-01 19:42 ` Christian Brauner
2019-04-01 21:30 ` Linus Torvalds
2019-04-01 21:30 ` Linus Torvalds
2019-04-01 21:58 ` Jonathan Kowalski
2019-04-01 21:58 ` Jonathan Kowalski
2019-04-01 22:13 ` Linus Torvalds
2019-04-01 22:13 ` Linus Torvalds
2019-04-01 22:34 ` Daniel Colascione
2019-04-01 22:34 ` Daniel Colascione
2019-04-01 16:07 ` Jonathan Kowalski
2019-04-01 16:07 ` Jonathan Kowalski
2019-04-01 16:15 ` Linus Torvalds
2019-04-01 16:15 ` Linus Torvalds
2019-04-01 16:27 ` Jonathan Kowalski
2019-04-01 16:27 ` Jonathan Kowalski
2019-04-01 16:21 ` Daniel Colascione
2019-04-01 16:21 ` Daniel Colascione
2019-04-01 16:29 ` Linus Torvalds
2019-04-01 16:29 ` Linus Torvalds
2019-04-01 16:45 ` Daniel Colascione
2019-04-01 16:45 ` Daniel Colascione
2019-04-01 17:00 ` David Laight
2019-04-01 17:00 ` David Laight
2019-04-01 17:32 ` Linus Torvalds [this message]
2019-04-01 17:32 ` Linus Torvalds
2019-04-02 11:03 ` Florian Weimer
2019-04-02 11:03 ` Florian Weimer
2019-04-01 16:10 ` Andy Lutomirski
2019-04-01 16:10 ` Andy Lutomirski
2019-04-01 12:04 ` Christian Brauner
2019-04-01 12:04 ` Christian Brauner
2019-04-01 13:43 ` Jann Horn
2019-04-01 13:43 ` Jann Horn
2019-03-31 21:19 ` Christian Brauner
2019-03-31 21:19 ` Christian Brauner
2019-03-30 16:37 ` Christian Brauner
2019-03-30 16:37 ` Christian Brauner
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