mm/page-writeback.c: fix divide by zero in bdi_dirty_limits()
authorMaxim Patlasov <MPatlasov@parallels.com>
Wed, 30 Jul 2014 23:08:21 +0000 (16:08 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 7 Aug 2014 23:53:51 +0000 (16:53 -0700)
commit3f7d325fbbe12e5ade71a1f90759c06ed2d27e3c
tree573d3999186b474b46f13ba9d4ab6a06115149ae
parent019c805ef259da95d563a562d5696ca4cd334177
mm/page-writeback.c: fix divide by zero in bdi_dirty_limits()

commit f6789593d5cea42a4ecb1cbeab6a23ade5ebbba7 upstream.

Under memory pressure, it is possible for dirty_thresh, calculated by
global_dirty_limits() in balance_dirty_pages(), to equal zero.  Then, if
strictlimit is true, bdi_dirty_limits() tries to resolve the proportion:

  bdi_bg_thresh : bdi_thresh = background_thresh : dirty_thresh

by dividing by zero.

Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/page-writeback.c