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Subject: Re: [PATCH 1/3] mm/vmalloc: fix size check for
 remap_vmalloc_range_partial()
To:     Roman Penyaev <rpenyaev@suse.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>, Joe Perches <joe@perches.com>,
        "Luis R. Rodriguez" <mcgrof@kernel.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
References: <20190103145954.16942-1-rpenyaev@suse.de>
 <20190103145954.16942-2-rpenyaev@suse.de>
From:   Andrey Ryabinin <aryabinin@virtuozzo.com>
Message-ID: <873d9ee8-9cee-b6f1-ca2c-f4da2d2ddfc0@virtuozzo.com>
Date:   Fri, 11 Jan 2019 22:19:12 +0300
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On 1/3/19 5:59 PM, Roman Penyaev wrote:
> area->size can include adjacent guard page but get_vm_area_size()
> returns actual size of the area.
> 
> This fixes possible kernel crash when userspace tries to map area
> on 1 page bigger: size check passes but the following vmalloc_to_page()
> returns NULL on last guard (non-existing) page.
> 
> Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Cc: Joe Perches <joe@perches.com>
> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Cc: stable@vger.kernel.org
> ---

Fixes: e69e9d4aee71 ("vmalloc: introduce remap_vmalloc_range_partial")
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>