From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Torvald Riegel <triegel@redhat.com>
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 12:05:00 -0000 [thread overview]
Message-ID: <56B1ECEF.6060604@linaro.org> (raw)
In-Reply-To: <1454497614.4592.392.camel@localhost.localdomain>
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.
next prev parent reply other threads:[~2016-02-03 12:05 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 v4 2/3] posix: execvpe cleanup 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 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 [this message]
2016-02-03 12:06 ` Torvald Riegel
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56B1ECEF.6060604@linaro.org \
--to=adhemerval.zanella@linaro.org \
--cc=fweimer@redhat.com \
--cc=libc-alpha@sourceware.org \
--cc=triegel@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).