Groups > linux.kernel > #1620852

clear_page, copy_page address align question?

From	Minchan Kim <minchan@kernel.org>
Newsgroups	linux.kernel
Subject	clear_page, copy_page address align question?
Date	2017-04-11 05:10 +0200
Message-ID	<tuUlP-1p3-5@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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Hello,

When I tested zram in ppc64, I got random corruption.
With investigation, it seems clear_page corrupted the memory.
I passed 64K kmalloced(kmalloc(PAGE_SIZE)) address to clear_page
and turned on slub debug so address is not aligned with PAGE_SIZE.
Is it a valid usecase that non-PAGE_SIZE aligned address is
used for clear_page in ppc64?

As well, copy_page have same rule, too?

Anyway, when I changed clear_page to memset, it seems the problem
is gone.

Thanks.

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clear_page, copy_page address align question? Minchan Kim <minchan@kernel.org> - 2017-04-11 05:10 +0200
  Re: clear_page, copy_page address align question? Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-04-11 05:20 +0200
    Re: clear_page, copy_page address align question? Minchan Kim <minchan@kernel.org> - 2017-04-11 05:30 +0200

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