From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: Yann Droneaud <ydroneaud@opteya.com>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
David Ahern <dsahern@gmail.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Mike Galbraith <efault@gmx.de>,
Stephane Eranian <eranian@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Michael Ellerman <michael@ellerman.id.au>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf tools: enable close-on-exec flag on perf file descriptor
Date: Mon, 6 Jan 2014 17:39:50 +0100 [thread overview]
Message-ID: <20140106163950.GP31570@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140106162754.GE27909@tassilo.jf.intel.com>
On Mon, Jan 06, 2014 at 08:27:54AM -0800, Andi Kleen wrote:
> On Mon, Jan 06, 2014 at 11:51:25AM +0100, Yann Droneaud wrote:
> > In a previous patch [1][2], flag PERF_FLAG_FD_CLOEXEC was
> > added to perf_event_open(2) syscall to allows userspace
> > to enable close-on-exec behavor atomically when creating
> > the file descriptor.
> >
> > This patch makes perf tools use the new flag.
>
> What is that good for? I can see why for a threaded program, but
> "perf" is not threaded.
AFAICT its got nothing to do with threaded or not, but only with exec()
and we do in fact call exec() quite a lot in perf.
It ensures we do not leak open perf FDs into our child processes. Now
I'm not entirely sure how we do the exec these days but I think we were
good about not not leaking them anyway, but more paranoia never really
hurts.
next prev parent reply other threads:[~2014-01-06 16:40 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-05 20:36 [PATCH v5 0/7] Getting rid of get_unused_fd() / enable close-on-exec Yann Droneaud
2014-01-05 20:36 ` Yann Droneaud
2014-01-05 20:36 ` Yann Droneaud
2014-01-05 20:36 ` [PATCHv5 1/7] ia64: use get_unused_fd_flags(0) instead of get_unused_fd() Yann Droneaud
2014-01-05 20:36 ` Yann Droneaud
2014-01-05 20:36 ` [PATCHv5 2/7] ppc/cell: " Yann Droneaud
2014-01-05 20:36 ` Yann Droneaud
2014-01-05 20:36 ` [PATCHv5 3/7] binfmt_misc: " Yann Droneaud
2014-01-05 20:36 ` [PATCHv5 4/7] file: " Yann Droneaud
2014-01-05 20:36 ` [PATCHv5 5/7] fanotify: enable close-on-exec on events' fd when requested in fanotify_init() Yann Droneaud
2014-01-20 17:15 ` Yann Droneaud
2014-01-05 20:36 ` [PATCHv5 6/7] perf: introduce a flag to enable close-on-exec in perf_event_open() Yann Droneaud
2014-01-06 9:29 ` Peter Zijlstra
2014-01-06 10:51 ` [PATCH] perf tools: enable close-on-exec flag on perf file descriptor Yann Droneaud
2014-01-06 11:24 ` Peter Zijlstra
2014-01-06 14:43 ` Arnaldo Carvalho de Melo
2014-01-06 21:01 ` Yann Droneaud
2014-01-06 21:14 ` Arnaldo Carvalho de Melo
2014-01-06 14:22 ` Jiri Olsa
2014-01-06 15:31 ` Yann Droneaud
2014-01-06 16:27 ` Andi Kleen
2014-01-06 16:39 ` Peter Zijlstra [this message]
2014-01-06 16:52 ` Andi Kleen
2014-01-06 17:15 ` Yann Droneaud
2014-01-11 18:07 ` [PATCHv1] " Yann Droneaud
2014-01-13 10:09 ` [PATCHv2] " Yann Droneaud
2014-01-15 18:50 ` Arnaldo Carvalho de Melo
2014-01-26 21:20 ` [PATCHv3] " Yann Droneaud
2014-03-11 8:39 ` [PATCHv4] " Yann Droneaud
2014-06-02 10:56 ` [PATCHv5] " Yann Droneaud
2014-06-02 19:23 ` Jiri Olsa
2014-06-03 8:57 ` Yann Droneaud
2014-06-03 9:23 ` Adrian Hunter
2014-06-03 11:51 ` Jiri Olsa
2014-06-30 20:28 ` [PATCHv6] " Yann Droneaud
2014-07-12 23:28 ` Jiri Olsa
2014-01-12 18:43 ` [tip:perf/core] perf: Introduce a flag to enable close-on-exec in perf_event_open() tip-bot for Yann Droneaud
2014-01-05 20:36 ` [PATCHv5 7/7] file: remove macro get_unused_fd() Yann Droneaud
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