From: Oleg Nesterov <oleg@redhat.com>
To: Aleksa Sarai <cyphar@cyphar.com>
Cc: Christian Brauner <christian@brauner.io>,
jannh@google.com, viro@zeniv.linux.org.uk,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
arnd@arndb.de, akpm@linux-foundation.org, dhowells@redhat.com,
ebiederm@xmission.com, elena.reshetova@intel.com,
keescook@chromium.org, luto@amacapital.net, luto@kernel.org,
tglx@linutronix.de, linux-alpha@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org,
linux-api@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kselftest@vger.kernel.org, joel@joelfernandes.org,
dancol@google.com, serge@hallyn.com,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [PATCH v1 1/2] pid: add pidfd_open()
Date: Thu, 16 May 2019 17:06:12 +0200 [thread overview]
Message-ID: <20190516150611.GC22564@redhat.com> (raw)
In-Reply-To: <20190516145607.j43xyj26k6l5vmbd@yavin>
On 05/17, Aleksa Sarai wrote:
>
> On 2019-05-16, Oleg Nesterov <oleg@redhat.com> wrote:
> > On 05/16, Christian Brauner wrote:
> > >
> > > With the introduction of pidfds through CLONE_PIDFD it is possible to
> > > created pidfds at process creation time.
> >
> > Now I am wondering why do we need CLONE_PIDFD, you can just do
> >
> > pid = fork();
> > pidfd_open(pid);
>
> While the race window would be exceptionally short, there is the
> possibility that the child will die
Yes,
> and their pid will be recycled
> before you do pidfd_open().
No.
Unless the caller's sub-thread does wait() before pidfd_open(), of course.
Or unless you do signal(SIGCHILD, SIG_IGN).
Oleg.
next prev parent reply other threads:[~2019-05-16 15:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-16 13:59 [PATCH v1 1/2] pid: add pidfd_open() Christian Brauner
2019-05-16 13:59 ` [PATCH v1 2/2] tests: add pidfd_open() tests Christian Brauner
2019-05-16 14:27 ` [PATCH v1 1/2] pid: add pidfd_open() Oleg Nesterov
2019-05-16 14:56 ` Aleksa Sarai
2019-05-16 15:06 ` Oleg Nesterov [this message]
2019-05-16 15:12 ` Aleksa Sarai
2019-05-16 15:22 ` Oleg Nesterov
2019-05-16 15:29 ` Christian Brauner
2019-05-16 14:57 ` Christian Brauner
2019-05-16 14:56 ` Geert Uytterhoeven
2019-05-16 14:58 ` Christian Brauner
2019-05-18 9:48 ` Joel Fernandes
2019-05-18 10:04 ` Christian Brauner
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