linux-kernel - Re: futex(2) man page update help request

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Date:	Thu, 15 May 2014 15:46:51 +0200
From:	"Michael Kerrisk (man-pages)" <mtk.manpages@...il.com>
To:	Darren Hart <dvhart@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, Jakub Jelinek <jakub@...hat.com>
CC:	mtk.manpages@...il.com,
	"linux-man@...r.kernel.org" <linux-man@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Davidlohr Bueso <davidlohr.bueso@...com>,
	Arnd Bergmann <arnd@...db.de>,
	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Linux API <linux-api@...r.kernel.org>,
	Carlos O'Donell <carlos@...hat.com>
Subject: Re: futex(2) man page update help request

On 05/15/2014 07:21 AM, Darren Hart wrote:
> On 5/14/14, 17:18, "H. Peter Anvin" <hpa@...or.com> wrote:
> 
>> On 05/14/2014 09:18 AM, Darren Hart wrote:
>>>
>>> However, unless I'm sorely mistaken, the larger problem is that glibc
>>> removed the futex() call entirely, so these man pages don't describe
>>> something users even have access to anymore. I had to revert to calling
>>> the syscalls directly in the futextest test suite because of this:
>>>
>>>
>>> http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/tree/inc
>>> lu
>>> de/futextest.h#n67
>>>
>>
>> This really comes down to the fact that we should have a libinux which
>> contains the basic system call wrapper machinery for Linux specific
>> things and nothing else.
>>
>> syscall(3) is toxic and breaks randomly on some platforms.
> 
> Peter Z and I have had a good time discussing this in the past.... And
> here it is again. :-)

People have a number of times noted that there are problems
with syscall(), but I'm not knowledgeable on the details.
I'd happily take a patch to the man page (which, for historical
reasons, is actually syscall(2)) that explains the the problems 
(and ideally notes those platforms where there are no problems).

Thanks,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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