| Message ID | 1407448542-26239-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index d013dba..9f45f87 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
This is a note to let you know that I have just added a patch titled mm/page-writeback.c: fix divide by zero in bdi_dirty_limits() to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11.6. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From fbeb558dcf5f518b2a75949428cb1b88ebc92b69 Mon Sep 17 00:00:00 2001 From: Maxim Patlasov <MPatlasov@parallels.com> Date: Wed, 30 Jul 2014 16:08:21 -0700 Subject: 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: Kamal Mostafa <kamal@canonical.com> --- mm/page-writeback.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) -- 1.9.1