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Date: Tue, 24 Apr 2012 11:12:15 -0400
From: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
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CC: Cyrill Gorcunov <gorcunov@openvz.org>,
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        LKML <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
        Andrew Morton <akpm@osdl.org>, kosaki.motohiro@gmail.com
Subject: Re: Bad error return after find_vma() in PR_SET_MM code
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(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.