1. 09 May, 2017 35 commits
  2. 03 May, 2017 4 commits
  3. 28 Apr, 2017 1 commit
    • Minchan Kim's avatar
      zram: do not use copy_page with non-page aligned address · b356df1b
      Minchan Kim authored
      commit d72e9a7a upstream.
      
      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: 42e99bd9 ("zram: optimize memory operations with clear_page()/copy_page()")
      Link: http://lkml.kernel.org/r/1492042622-12074-2-git-send-email-minchan@kernel.orgSigned-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      
      b356df1b