From: Carlos O'Donell <carlos@redhat.com>
To: Florian Weimer <fweimer@redhat.com>,
Carlos O'Donell via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH] manual: Add note to process.texi about MT-process fork (Bug 30159)
Date: Thu, 23 Feb 2023 17:39:34 -0500 [thread overview]
Message-ID: <0f4e83b2-974f-df06-23c5-ef0750488814@redhat.com> (raw)
In-Reply-To: <871qmg2hm6.fsf@oldenburg.str.redhat.com>
On 2/23/23 16:32, Florian Weimer wrote:
> * Carlos O'Donell via Libc-alpha:
>
>> The forked child of an MT-process may only call AS-safe functions.
>> ---
>> manual/process.texi | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/manual/process.texi b/manual/process.texi
>> index 9307379194..dfdf0923b4 100644
>> --- a/manual/process.texi
>> +++ b/manual/process.texi
>> @@ -316,6 +316,12 @@ The child doesn't inherit alarms set by the parent process.
>> The set of pending signals (@pxref{Delivery of Signal}) for the child
>> process is cleared. (The child process inherits its mask of blocked
>> signals and signal actions from the parent process.)
>> +
>> +@item
>> +In the case of a multi-threaded parent, the child process may only
>> +safely call asynchronous-signal-safe functions until the process is
>> +replaced with a call to an @code{exec} family function.
>
> We support calling malloc after fork as an extension. For example,
> calling opendir after fork to find file descriptors in /proc/self/fd is
> fairly common.
We support calling a lot of things in reality, but I didn't want to over commit
with this change to the manual. I like your narrowly worded addition.
> Perhaps add:
>
> As an extension relative to POSIX, @theglibc{} supports calling
> @code{malloc} and other allocation functions after @code{fork}. This
> only applies to the standard @code{malloc}. Whether this extension is
> supported by replacement @code{malloc} implementations depends on the
> replacement. @xref{Replacing malloc}.
v2 posted:
https://patchwork.sourceware.org/project/glibc/patch/20230223223728.423748-1-carlos@redhat.com/
Checked pdf/html/texi builds and the xref and macros look good.
--
Cheers,
Carlos.
prev parent reply other threads:[~2023-02-23 22:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-23 20:49 Carlos O'Donell
2023-02-23 21:32 ` Florian Weimer
2023-02-23 22:39 ` Carlos O'Donell [this message]
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=0f4e83b2-974f-df06-23c5-ef0750488814@redhat.com \
--to=carlos@redhat.com \
--cc=fweimer@redhat.com \
--cc=libc-alpha@sourceware.org \
/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).