From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
David Rientjes <rientjes@google.com>,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH] mm/mempolicy.c: do not put mempolicy before using its nodemask
Date: Wed, 18 Jan 2017 20:04:45 +0300 [thread overview]
Message-ID: <20170118170444.s4z5jqn57fqbnvnf@black.fi.intel.com> (raw)
In-Reply-To: <20170118141124.8345-1-vbabka@suse.cz>
On Wed, Jan 18, 2017 at 03:11:24PM +0100, Vlastimil Babka wrote:
> Since commit be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to
> alloc_pages_vma") alloc_pages_vma() can potentially free a mempolicy by
> mpol_cond_put() before accessing the embedded nodemask by
> __alloc_pages_nodemask(). The commit log says it's so "we can use a single
> exit path within the function" but that's clearly wrong. We can still do that
> when doing mpol_cond_put() after the allocation attempt.
>
> Make sure the mempolicy is not freed prematurely, otherwise
> __alloc_pages_nodemask() can end up using a bogus nodemask, which could lead
> e.g. to premature OOM.
>
> Fixes: be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to alloc_pages_vma")
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: stable@vger.kernel.org
> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
Looks good to me.
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
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next prev parent reply other threads:[~2017-01-18 17:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-18 14:11 Vlastimil Babka
2017-01-18 17:04 ` Kirill A. Shutemov [this message]
2017-01-18 19:03 ` Michal Hocko
2017-01-18 21:34 ` David Rientjes
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