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Commit 3a73dbbc authored by Wu Fengguang's avatar Wu Fengguang
Browse files

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: default avatarWitold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
parent 31555213

mm/page-writeback.c

+4 −4
Original line number Original line Diff line number Diff line
@@ -1097,13 +1097,13 @@ static void balance_dirty_pages(struct address_space *mapping, 
		pos_ratio = bdi_position_ratio(bdi, dirty_thresh,

		pos_ratio = bdi_position_ratio(bdi, dirty_thresh,

					       background_thresh, nr_dirty,

					       background_thresh, nr_dirty,

					       bdi_thresh, bdi_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;

			pause = max_pause;

			goto pause;

			goto pause;

		}

		}

		task_ratelimit = (u64)dirty_ratelimit *

		pause = HZ * pages_dirtied / task_ratelimit;

					pos_ratio >> RATELIMIT_CALC_SHIFT;

		pause = (HZ * pages_dirtied) / (task_ratelimit | 1);

		if (unlikely(pause <= 0)) {

		if (unlikely(pause <= 0)) {

			trace_balance_dirty_pages(bdi,

			trace_balance_dirty_pages(bdi,

						  dirty_thresh,

						  dirty_thresh,