From: Torvald Riegel <triegel@redhat.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>, libc-alpha@sourceware.org
Subject: Re: [PATCH v2 3/3] posix: New Linux posix_spawn{p} implementation
Date: Wed, 03 Feb 2016 12:06:00 -0000 [thread overview]
Message-ID: <1454501204.4592.393.camel@localhost.localdomain> (raw)
In-Reply-To: <56B1ECEF.6060604@linaro.org>
On Wed, 2016-02-03 at 10:05 -0200, Adhemerval Zanella wrote:
>
> On 03-02-2016 09:06, Torvald Riegel wrote:
> > On Tue, 2016-02-02 at 11:31 -0200, Adhemerval Zanella wrote:
> >>
> >> On 02-02-2016 11:05, Florian Weimer wrote:
> >>> On 02/01/2016 05:21 PM, Adhemerval Zanella wrote:
> >>>
> >>>> + new_pid = CLONE (__spawni_child, STACK (stack, stack_size),
> >>>> + CLONE_VM | CLONE_VFORK | SIGCHLD, &args);
> >>>
> >>> Does this set up new per-thread variables? Otherwise, errno in the
> >>> parent and child will be same and the code still has races.
> >>>
> >>> Florian
> >>>
> >>
> >> Could you elaborate? In my understanding there is no requirement of
> >> using CLONE_SETTLS to avoid races: CLONE_VFORK will suspend the
> >> calling process and even with child using the same TLS namespace as
> >> the parent there will be no concurrent access between them.
> >
> > Whatever you agree on eventually, it sounds as if this should be
> > documented as part of the concurrency notes for this function.
> >
>
> I think it is worth to comment internally on the function implementation
> about the CLONE_VFORK synchronization, but since it is transparent
> to user (the function will either spawn a new process or fails and it can
> be either through a syscall, {v}fork/exec or any other mechanism),
> I do not see why expose these implementation details explicit.
I meant the internal documentation; IOW, comments in the code.
next prev parent reply other threads:[~2016-02-03 12:06 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-01 16:21 [PATCH 0/3] posix: Execute file function fixes Adhemerval Zanella
2016-02-01 16:21 ` [PATCH v2 1/3] posix: Remove dynamic memory allocation from execl{e,p} Adhemerval Zanella
2016-02-01 16:52 ` Joseph Myers
2016-02-01 17:18 ` Adhemerval Zanella
2016-02-01 17:54 ` Joseph Myers
2016-02-01 18:09 ` Adhemerval Zanella
2016-02-02 11:24 ` Florian Weimer
2016-02-02 12:46 ` Szabolcs Nagy
2016-02-02 12:47 ` Adhemerval Zanella
2016-02-02 16:33 ` Rich Felker
2016-02-07 21:28 ` Rasmus Villemoes
2016-02-09 11:36 ` Richard Henderson
2016-02-09 13:30 ` Szabolcs Nagy
2016-02-10 16:36 ` Adhemerval Zanella
2016-02-01 16:21 ` [PATCH v4 2/3] posix: execvpe cleanup Adhemerval Zanella
2016-02-01 16:21 ` [PATCH v2 3/3] posix: New Linux posix_spawn{p} implementation Adhemerval Zanella
2016-02-02 13:06 ` Florian Weimer
2016-02-02 13:31 ` Adhemerval Zanella
2016-02-03 11:07 ` Torvald Riegel
2016-02-03 12:05 ` Adhemerval Zanella
2016-02-03 12:06 ` Torvald Riegel [this message]
2016-02-03 12:14 ` Adhemerval Zanella
2016-08-31 21:13 ` Rasmus Villemoes
2016-08-31 22:08 ` Joseph Myers
2016-09-01 9:28 ` Rasmus Villemoes
2016-09-14 13:13 ` Adhemerval Zanella
2016-09-14 18:58 ` Rasmus Villemoes
2016-09-14 19:59 ` Adhemerval Zanella
2016-09-20 20:25 ` Florian Weimer
2016-09-20 20:54 ` Rasmus Villemoes
2016-09-20 21:01 ` [PATCH] linux: spawni.c: simplify error reporting to parent Rasmus Villemoes
2016-09-22 20:54 ` Adhemerval Zanella
2016-09-23 5:21 ` Florian Weimer
2016-09-23 19:09 ` Rasmus Villemoes
2016-09-23 19:28 ` Adhemerval Zanella
2016-09-23 20:37 ` Florian Weimer
2016-09-27 20:26 ` Rasmus Villemoes
2016-09-27 21:14 ` Adhemerval Zanella
2016-09-28 14:14 ` Rich Felker
2016-09-28 15:03 ` Andreas Schwab
2016-09-28 15:22 ` Rich Felker
2016-09-28 18:13 ` Adhemerval Zanella
2016-10-06 12:52 ` Florian Weimer
2016-09-06 20:43 ` [PATCH v2 3/3] posix: New Linux posix_spawn{p} implementation Rasmus Villemoes
2016-09-14 19:37 ` Adhemerval Zanella
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