[PATCH] mm/damon/tests/vaddr-kunit: don't use mas_lock for MM_MT_FLAGS-initialized maple tree

[SeongJae Park]

damon_test_three_regions_in_vmas() initializes a maple tree with
MM_MT_FLAGS.  The flags contains MT_FLAGS_LOCK_EXTERN, which means
mt_lock of the maple tree will not be used.  And therefore the maple
tree initialization code skips initialization of the mt_lock.  However,
__link_vmas(), which adds vmas for test to the maple tree, uses the
mt_lock.  In other words, the uninitialized spinlock is used.  The
problem becomes celar when spinlock debugging is turned on, since it
reports spinlock bad magic bug.  Fix the issue by not using the mt_lock
as promised.

Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Closes: https://lore.kernel.org/1453b2b2-6119-4082-ad9e-f3c5239bf87e@xxxxxxxxxxxx
Fixes: d0cf3dd47f0d ("damon: convert __damon_va_three_regions to use the VMA iterator")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
 mm/damon/tests/vaddr-kunit.h | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
index 83626483f82b..c6c7e0e0ab07 100644
--- a/mm/damon/tests/vaddr-kunit.h
+++ b/mm/damon/tests/vaddr-kunit.h
@@ -17,23 +17,19 @@
 static int __link_vmas(struct maple_tree *mt, struct vm_area_struct *vmas,
 			ssize_t nr_vmas)
 {
-	int i, ret = -ENOMEM;
+	int i;
 	MA_STATE(mas, mt, 0, 0);
 
 	if (!nr_vmas)
 		return 0;
 
-	mas_lock(&mas);
 	for (i = 0; i < nr_vmas; i++) {
 		mas_set_range(&mas, vmas[i].vm_start, vmas[i].vm_end - 1);
 		if (mas_store_gfp(&mas, &vmas[i], GFP_KERNEL))
-			goto failed;
+			return -ENOMEM;
 	}
 
-	ret = 0;
-failed:
-	mas_unlock(&mas);
-	return ret;
+	return 0;
 }
 
 /*
-- 
2.39.2