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Date: Fri, 14 Apr 2017 14:41:05 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        kernel-team@lge.com, stable@vger.kernel.org
Subject: Re: [PATCH 2/3] zram: do not use copy_page with non-page alinged
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Hello,

On (04/13/17 09:17), Minchan Kim wrote:
> The copy_page is optimized memcpy for page-alinged address.
> If it is used with non-page aligned address, it can corrupt memory which
> means system corruption. With zram, it can happen with
> 
> 1. 64K architecture
> 2. partial IO
> 3. slub debug
> 
> Partial IO need to allocate a page and zram allocates it via kmalloc.
> With slub debug, kmalloc(PAGE_SIZE) doesn't return page-size aligned
> address. And finally, copy_page(mem, cmem) corrupts memory.

which would be the case for many other copy_page() calls in the kernel.
right? if so - should the fix be in copy_page() then?

	-ss