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From: Oleg Nesterov <oleg@redhat.com>
To: Thiago Macieira <thiago.macieira@intel.com>
Cc: Josh Triplett <josh@joshtriplett.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Rik van Riel <riel@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v2 5/7] clone4: Add a CLONE_AUTOREAP flag to automatically reap the child process
Date: Fri, 20 Mar 2015 20:09:14 +0100	[thread overview]
Message-ID: <20150320190914.GA28357@redhat.com> (raw)
In-Reply-To: <1766646.jusoNDOCPE@tjmaciei-mobl4>

On 03/20, Thiago Macieira wrote:
>
> On Friday 20 March 2015 19:14:04 Oleg Nesterov wrote:
> > Also. I forgot that the kernel always resets ->exit_signal to SIGCHLD on
> > exec or reparenting. Reparenting is probably fine. But what about exec?
> > Should it keep ->exit_signal == 0 if "autoreap" ? I think it should not, to
> > avoid the strange special case.
>
> Not delivering any signal was the objective of this patch series, so yes
> exit_signal == 0 should survive an exec and even re-exec.

OK, but then perhaps we should never send SIGCHLD (on exit) if "autoreap",
to make the logic simple.

And copy_process() should probably do

	if ((clone_flags & CSIGNAL) && (clone_flags && CLONE_AUTOREAP))
		return -EINVAL;

so that we still can change this behaviour later.

Oleg.


WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Thiago Macieira
	<thiago.macieira-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>,
	Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	"Paul E. McKenney"
	<paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
	"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	Rik van Riel <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	Michael Kerrisk
	<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
Subject: Re: [PATCH v2 5/7] clone4: Add a CLONE_AUTOREAP flag to automatically reap the child process
Date: Fri, 20 Mar 2015 20:09:14 +0100	[thread overview]
Message-ID: <20150320190914.GA28357@redhat.com> (raw)
In-Reply-To: <1766646.jusoNDOCPE@tjmaciei-mobl4>

On 03/20, Thiago Macieira wrote:
>
> On Friday 20 March 2015 19:14:04 Oleg Nesterov wrote:
> > Also. I forgot that the kernel always resets ->exit_signal to SIGCHLD on
> > exec or reparenting. Reparenting is probably fine. But what about exec?
> > Should it keep ->exit_signal == 0 if "autoreap" ? I think it should not, to
> > avoid the strange special case.
>
> Not delivering any signal was the objective of this patch series, so yes
> exit_signal == 0 should survive an exec and even re-exec.

OK, but then perhaps we should never send SIGCHLD (on exit) if "autoreap",
to make the logic simple.

And copy_process() should probably do

	if ((clone_flags & CSIGNAL) && (clone_flags && CLONE_AUTOREAP))
		return -EINVAL;

so that we still can change this behaviour later.

Oleg.

  reply	other threads:[~2015-03-20 19:11 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-15  7:59 [PATCH v2 0/7] CLONE_FD: Task exit notification via file descriptor Josh Triplett
2015-03-15  7:59 ` Josh Triplett
2015-03-15  7:59 ` [PATCH v2 1/7] clone: Support passing tls argument via C rather than pt_regs magic Josh Triplett
2015-03-15  7:59 ` [PATCH v2 2/7] x86: Opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit Josh Triplett
2015-03-15  7:59   ` Josh Triplett
2015-03-15  7:59 ` [PATCH v2 3/7] Introduce a new clone4 syscall with more flag bits and extensible arguments Josh Triplett
2015-03-23 14:11   ` David Drysdale
2015-03-23 14:11     ` David Drysdale
2015-03-23 15:05     ` josh
2015-03-31 14:41       ` David Drysdale
2015-03-15  7:59 ` [PATCH v2 4/7] kernel/fork.c: Pass arguments to _do_fork and copy_process using clone4_args Josh Triplett
2015-03-15  8:00 ` [PATCH v2 5/7] clone4: Add a CLONE_AUTOREAP flag to automatically reap the child process Josh Triplett
2015-03-15 14:52   ` Oleg Nesterov
2015-03-15 14:52     ` Oleg Nesterov
2015-03-15 17:18     ` Josh Triplett
2015-03-15 17:18       ` Josh Triplett
2015-03-15 19:55       ` Oleg Nesterov
2015-03-15 19:55         ` Oleg Nesterov
2015-03-15 23:34         ` Josh Triplett
2015-03-15 23:34           ` Josh Triplett
2015-03-20 18:14           ` Oleg Nesterov
2015-03-20 18:46             ` Thiago Macieira
2015-03-20 19:09               ` Oleg Nesterov [this message]
2015-03-20 19:09                 ` Oleg Nesterov
2015-03-20 21:10                 ` josh
2015-03-15  8:00 ` [PATCH v2 6/7] signal: Factor out a helper function to process task_struct exit_code Josh Triplett
2015-03-15  8:00 ` [PATCH v2 7/7] clone4: Add a CLONE_FD flag to get task exit notification via fd Josh Triplett
2015-03-23 17:38   ` David Drysdale
2015-03-25 14:53     ` Josh Triplett
2015-04-06  8:30   ` Sergey Senozhatsky
2015-04-06  8:30     ` Sergey Senozhatsky
2015-04-06  9:31     ` Josh Triplett
2015-04-06  9:31       ` Josh Triplett
2015-03-15  8:00 ` [PATCH v2 man-pages] clone4.2: New manpage documenting clone4(2) Josh Triplett
2015-03-15  8:04 ` [PATCH v2 0/7] CLONE_FD: Task exit notification via file descriptor Josh Triplett
2015-03-15  8:04   ` Josh Triplett
2015-03-16 21:44 ` Kees Cook
2015-03-16 21:44   ` Kees Cook
2015-03-16 22:14   ` Thiago Macieira
2015-03-16 22:14     ` Thiago Macieira
2015-03-16 22:36     ` Kees Cook
2015-03-16 22:50       ` Thiago Macieira
2015-03-16 22:50         ` Thiago Macieira
2015-03-16 23:26         ` Kees Cook
2015-03-16 23:35       ` josh
2015-03-16 23:29     ` josh
2015-03-16 23:29       ` josh-iaAMLnmF4UmaiuxdJuQwMA
2015-03-17  0:49       ` Thiago Macieira
2015-03-17  0:49         ` Thiago Macieira
2015-03-23 14:12       ` David Drysdale
2015-03-23 15:03         ` josh
2015-03-16 23:25   ` josh
2015-03-16 23:25     ` josh-iaAMLnmF4UmaiuxdJuQwMA
2015-03-31 20:08 ` Jonathan Corbet
2015-03-31 22:02   ` josh
2015-04-01  7:24     ` Jonathan Corbet
2015-04-09  2:19       ` Josh Triplett
2015-04-09  2:19         ` Josh Triplett
2015-05-29  7:43 ` Florian Weimer
2015-05-29  7:43   ` Florian Weimer
2015-05-29 20:27   ` Thiago Macieira
2015-06-15 10:06     ` Florian Weimer
2015-06-15 10:06       ` Florian Weimer

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