1. 19 Jan, 2017 38 commits
  2. 15 Jan, 2017 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.4.43 · d9ea51a9
      Greg Kroah-Hartman authored
      d9ea51a9
    • Oliver O'Halloran's avatar
      mm/init: fix zone boundary creation · e21901d7
      Oliver O'Halloran authored
      commit 90cae1fe upstream.
      
      As a part of memory initialisation the architecture passes an array to
      free_area_init_nodes() which specifies the max PFN of each memory zone.
      This array is not necessarily monotonic (due to unused zones) so this
      array is parsed to build monotonic lists of the min and max PFN for each
      zone.  ZONE_MOVABLE is special cased here as its limits are managed by
      the mm subsystem rather than the architecture.  Unfortunately, this
      special casing is broken when ZONE_MOVABLE is the not the last zone in
      the zone list.  The core of the issue is:
      
      	if (i == ZONE_MOVABLE)
      		continue;
      	arch_zone_lowest_possible_pfn[i] =
      		arch_zone_highest_possible_pfn[i-1];
      
      As ZONE_MOVABLE is skipped the lowest_possible_pfn of the next zone will
      be set to zero.  This patch fixes this bug by adding explicitly tracking
      where the next zone should start rather than relying on the contents
      arch_zone_highest_possible_pfn[].
      
      Thie is low priority.  To get bitten by this you need to enable a zone
      that appears after ZONE_MOVABLE in the zone_type enum.  As far as I can
      tell this means running a kernel with ZONE_DEVICE or ZONE_CMA enabled,
      so I can't see this affecting too many people.
      
      I only noticed this because I've been fiddling with ZONE_DEVICE on
      powerpc and 4.6 broke my test kernel.  This bug, in conjunction with the
      changes in Taku Izumi's kernelcore=mirror patch (d91749c1) and
      powerpc being the odd architecture which initialises max_zone_pfn[] to
      ~0ul instead of 0 caused all of system memory to be placed into
      ZONE_DEVICE at boot, followed a panic since device memory cannot be used
      for kernel allocations.  I've already submitted a patch to fix the
      powerpc specific bits, but I figured this should be fixed too.
      
      Link: http://lkml.kernel.org/r/1462435033-15601-1-git-send-email-oohall@gmail.comSigned-off-by: default avatarOliver O'Halloran <oohall@gmail.com>
      Cc: Anton Blanchard <anton@samba.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e21901d7