linux-kernel - Re: [Patch 1/2] ia32: use generic sys

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Message-ID: <20090912133014.GA5858@ZenIV.linux.org.uk>
Date:	Sat, 12 Sep 2009 14:30:14 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Amerigo Wang <amwang@...hat.com>, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [Patch 1/2] ia32: use generic sys_pipe()

On Tue, Aug 04, 2009 at 02:24:32PM +0200, Ingo Molnar wrote:

> Please _ALWAYS_ mention the change in behavior in the changelog, 
> just in case someone ends up bisecting it. I only found out when i 
> reviewed the two syscalls out of caution.
> 
> The syscall you remove kept stale fd's around in case of -EFAULT 
> from copy_to_user(). The generic version does an explicit close of 
> those files:
> 
>                         sys_close(fd[0]);
>                         sys_close(fd[1]);
>                         error = -EFAULT;

> The generic version looks like the better choice to me but this 
> difference should be mentioned in the changelog nevertheless, just 
> in case some buggy app runs into this issue.

It's not a matter of QOI, actually - sys32_pipe() is supposed to do what
sys_pipe() would do on i386 host.  So any difference in handling of an
error case is simply wrong.

Whether we want those sys_close() in sys_pipe() or not is a separate
question, but we definitely want the same behaviour when 32bit process is
run natively and when it's run on amd64.  So sys32_pipe() has no business
existing at all.
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