Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 35529357 authored by Vitaly Wool's avatar Vitaly Wool Committed by Linus Torvalds
Browse files

z3fold: fix stale list handling 



Fix the situation when clear_bit() is called for page->private before
the page pointer is actually assigned.  While at it, remove work_busy()
check because it is costly and does not give 100% guarantee anyway.

Signed-off-by: default avatarVitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6818600f

mm/z3fold.c

+2 −4
Original line number Diff line number Diff line
@@ -250,6 +250,7 @@ static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) 


	WARN_ON(!list_empty(&zhdr->buddy));

	set_bit(PAGE_STALE, &page->private);

	clear_bit(NEEDS_COMPACTING, &page->private);

	spin_lock(&pool->lock);

	if (!list_empty(&page->lru))

		list_del(&page->lru);
@@ -303,7 +304,6 @@ static void free_pages_work(struct work_struct *w) 
		list_del(&zhdr->buddy);

		if (WARN_ON(!test_bit(PAGE_STALE, &page->private)))

			continue;

		clear_bit(NEEDS_COMPACTING, &page->private);

		spin_unlock(&pool->stale_lock);

		cancel_work_sync(&zhdr->work);

		free_z3fold_page(page);
@@ -624,10 +624,8 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, 
	 * stale pages list. cancel_work_sync() can sleep so we must make

	 * sure it won't be called in case we're in atomic context.

	 */

	if (zhdr && (can_sleep || !work_pending(&zhdr->work) ||

	    !unlikely(work_busy(&zhdr->work)))) {

	if (zhdr && (can_sleep || !work_pending(&zhdr->work))) {

		list_del(&zhdr->buddy);

		clear_bit(NEEDS_COMPACTING, &page->private);

		spin_unlock(&pool->stale_lock);

		if (can_sleep)

			cancel_work_sync(&zhdr->work);