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Re: [PATCH 2/3] zram: do not use copy_page with non-page alinged address

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On Fri, Apr 14, 2017 at 02:41:05PM +0900, Sergey Senozhatsky wrote:
> 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?

I thought about it but was not sure it's good idea by several reasons
(but don't want to discuss it in this thread).

Anyway, it's stable stuff so I don't want to make the patch bloat.
If you believe it is right direction and valuable, you could be
a volunteer. :)

Thanks.

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[PATCH 1/3] zram: fix operator precedence to get offset Minchan Kim <minchan@kernel.org> - 2017-04-13 02:20 +0200
  [PATCH 3/3] zsmalloc: expand class bit Minchan Kim <minchan@kernel.org> - 2017-04-13 02:20 +0200
  [PATCH 2/3] zram: do not use copy_page with non-page alinged address Minchan Kim <minchan@kernel.org> - 2017-04-13 02:20 +0200
    Re: [PATCH 2/3] zram: do not use copy_page with non-page alinged  address Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-14 07:50 +0200
      Re: [PATCH 2/3] zram: do not use copy_page with non-page alinged  address Minchan Kim <minchan@kernel.org> - 2017-04-14 17:50 +0200
    Re: [PATCH 2/3] zram: do not use copy_page with non-page alinged  address Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-17 03:50 +0200
  Re: [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-14 07:10 +0200
    Re: [PATCH 1/3] zram: fix operator precedence to get offset Minchan Kim <minchan@kernel.org> - 2017-04-14 17:40 +0200
      Re: [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-17 03:30 +0200
        Re: [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-17 04:00 +0200
          Re: [PATCH 1/3] zram: fix operator precedence to get offset Minchan Kim <minchan@kernel.org> - 2017-04-17 04:20 +0200
            Re: [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-17 13:00 +0200
              Re: [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-17 13:00 +0200
              Re: [PATCH 1/3] zram: fix operator precedence to get offset Minchan Kim <minchan@kernel.org> - 2017-04-18 02:00 +0200
                Re: [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-18 04:00 +0200
                Re: [PATCH 1/3] zram: fix operator precedence to get offset Minchan Kim <minchan@kernel.org> - 2017-04-18 04:50 +0200
  Re: [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-17 03:30 +0200

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