Messages in this thread Patch in this message | | | Subject | [PATCH] mm/page-writeback.c: fix divide by zero in bdi_dirty_limits | From | Maxim Patlasov <> | Date | Fri, 11 Jul 2014 12:18:27 +0400 |
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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> --- 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 518e2c3..e0c9430 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1306,9 +1306,9 @@ 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
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