Minchan Kim d72e9a7a93 zram: do not use copy_page with non-page aligned address ... 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. So, this patch changes it to memcpy. Actuaully, we don't need to change zram_bvec_write part because zsmalloc returns page-aligned address in case of PAGE_SIZE class but it's not good to rely on the internal of zsmalloc. Note: When this patch is merged to stable, clear_page should be fixed, too. Unfortunately, recent zram removes it by "same page merge" feature so it's hard to backport this patch to -stable tree. I will handle it when I receive the mail from stable tree maintainer to merge this patch to backport. Fixes: 42e99bd ("zram: optimize memory operations with clear_page()/copy_page()") Link: http://lkml.kernel.org/r/1492042622-12074-2-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2017-04-13 18:24:21 -07:00
..
Kconfig	zram: delete custom lzo/lz4	2016-07-26 16:19:19 -07:00
Makefile	zram: delete custom lzo/lz4	2016-07-26 16:19:19 -07:00
zcomp.c	zram: Convert to hotplug state machine	2016-12-02 00:52:39 +01:00
zcomp.h	zram: Convert to hotplug state machine	2016-12-02 00:52:39 +01:00
zram_drv.c	zram: do not use copy_page with non-page aligned address	2017-04-13 18:24:21 -07:00
zram_drv.h	zram: extend zero pages to same element pages	2017-02-24 17:46:56 -08:00