diff options
| author | Maxim Patlasov <MPatlasov@parallels.com> | 2014-07-30 16:08:21 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-08-07 16:53:51 -0700 |
| commit | 3f7d325fbbe12e5ade71a1f90759c06ed2d27e3c (patch) | |
| tree | 573d3999186b474b46f13ba9d4ab6a06115149ae /mm | |
| parent | 019c805ef259da95d563a562d5696ca4cd334177 (diff) | |
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page-writeback.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 154af210178b..f972182d4218 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1324,9 +1324,9 @@ static inline void bdi_dirty_limits(struct backing_dev_info *bdi, *bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh); if (bdi_bg_thresh) - *bdi_bg_thresh = div_u64((u64)*bdi_thresh * - background_thresh, - dirty_thresh); + *bdi_bg_thresh = dirty_thresh ? div_u64((u64)*bdi_thresh * + background_thresh, + dirty_thresh) : 0; /* * In order to avoid the stacked BDI deadlock we need |