linux-kernel - Re: Bad error return after find_vma() in PR_SET

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Date:	Tue, 24 Apr 2012 19:15:44 +0400
From:	Cyrill Gorcunov <gorcunov@...nvz.org>
To:	KOSAKI Motohiro <kosaki.motohiro@...il.com>
Cc:	mtk.manpages@...il.com, Pavel Emelyanov <xemul@...allels.com>,
	linux-man@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	Tejun Heo <tj@...nel.org>, Andrew Morton <akpm@...l.org>
Subject: Re: Bad error return after find_vma() in PR_SET_MM code

On Tue, Apr 24, 2012 at 11:12:15AM -0400, KOSAKI Motohiro wrote:
> (4/15/12 12:00 AM), Michael Kerrisk (man-pages) wrote:
> >[Bother! Resending with corrected subject line (was "[PATCH 1/2]
> >prctl: Add PR_SET_MM option description")]
> >
> >Cyrill,
> >
> >While reviewing your patch to the prctl() manual page, I noticed the
> >following code in kernel/sys.c::prctl_set_mm():
> >
> >        if (opt != PR_SET_MM_START_BRK&&  opt != PR_SET_MM_BRK) {
> >                /* It must be existing VMA */
> >                if (!vma || vma->vm_start>  addr)
> >                        goto out;
> >        }
> >
> >At this point, the code causes an exit with error set to zero (i.e.,
> >success). This looks unintended to me. Is the code correct? I suspect
> >a return of -EFAULT or -ENOMEM is warranted.
> 
> EFAULT please when detecting invalid vma.

Thanks for reminder, Kosaki! I'll cook a patch asap.

	Cyrill
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