1 files changed, 17 insertions, 0 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 6ae8a66a704..94875b26592 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -639,6 +639,23 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
 	if (!trylock_page(page)) {
 		if (!force)
 			goto move_newpage;
+
+		/*
+		 * It's not safe for direct compaction to call lock_page.
+		 * For example, during page readahead pages are added locked
+		 * to the LRU. Later, when the IO completes the pages are
+		 * marked uptodate and unlocked. However, the queueing
+		 * could be merging multiple pages for one bio (e.g.
+		 * mpage_readpages). If an allocation happens for the
+		 * second or third page, the process can end up locking
+		 * the same page twice and deadlocking. Rather than
+		 * trying to be clever about what pages can be locked,
+		 * avoid the use of lock_page for direct compaction
+		 * altogether.
+		 */
+		if (current->flags & PF_MEMALLOC)
+			goto move_newpage;
+
 		lock_page(page);
 	}