From: Maxim Patlasov <mpatla...@parallels.com> 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 <mpatla...@parallels.com> Acked-by: Rik van Riel <r...@redhat.com> Cc: Michal Hocko <mho...@suse.cz> Cc: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com> Cc: Wu Fengguang <fengguang...@intel.com> Cc: Johannes Weiner <han...@cmpxchg.org> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Fixes: https://jira.sw.ru/browse/PSBM-40116 Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- Change since v1: Added reference to the upstream commit into changelog mm/page-writeback.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 2bb28ba..429c759 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1366,9 +1366,9 @@ 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 -- 2.4.9 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel