writeback: fix uninitialized task_ratelimit
In balance_dirty_pages() task_ratelimit may be not initialized
(initialization skiped by goto pause), and then used when calling
tracing hook.
Fix it by moving the task_ratelimit assignment before goto pause.
Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0360d1b..a3278f0 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1097,13 +1097,13 @@
pos_ratio = bdi_position_ratio(bdi, dirty_thresh,
background_thresh, nr_dirty,
bdi_thresh, bdi_dirty);
- if (unlikely(pos_ratio == 0)) {
+ task_ratelimit = ((u64)dirty_ratelimit * pos_ratio) >>
+ RATELIMIT_CALC_SHIFT;
+ if (unlikely(task_ratelimit == 0)) {
pause = max_pause;
goto pause;
}
- task_ratelimit = (u64)dirty_ratelimit *
- pos_ratio >> RATELIMIT_CALC_SHIFT;
- pause = (HZ * pages_dirtied) / (task_ratelimit | 1);
+ pause = HZ * pages_dirtied / task_ratelimit;
if (unlikely(pause <= 0)) {
trace_balance_dirty_pages(bdi,
dirty_thresh,