Commit 1f0bce2f authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Andrew Morton
Browse files

maple_tree: add testing for restoring maple state to active 

Restoring maple status to ma_active on overflow/underflow when mas->node
was NULL could have happened in the past, but was masked by a bug in
mas_walk().  Add test cases that triggered the bug when the node was
mas->node prior to fixing the maple state setup.

Add a few extra tests around restoring the active maple status.

Link: https://lore.kernel.org/all/202506191556.6bfc7b93-lkp@intel.com/
Link: https://lkml.kernel.org/r/20250624154823.52221-2-Liam.Howlett@oracle.com


Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: default avatarWei Yang <richard.weiyang@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 12f1d793

lib/test_maple_tree.c

+32 −0
Original line number Diff line number Diff line
@@ -3177,6 +3177,7 @@ static noinline void __init check_state_handling(struct maple_tree *mt) 
	void *entry, *ptr = (void *) 0x1234500;

	void *ptr2 = &ptr;

	void *ptr3 = &ptr2;

	unsigned long index;



	/* Check MAS_ROOT First */

	mtree_store_range(mt, 0, 0, ptr, GFP_KERNEL);
@@ -3706,6 +3707,37 @@ static noinline void __init check_state_handling(struct maple_tree *mt) 
	MT_BUG_ON(mt, mas.last != 0x1fff);

	MT_BUG_ON(mt, !mas_is_active(&mas));



	mas_unlock(&mas);

	mtree_destroy(mt);



	mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE);

	mas_lock(&mas);

	for (int count = 0; count < 30; count++) {

		mas_set(&mas, count);

		mas_store_gfp(&mas, xa_mk_value(count), GFP_KERNEL);

	}



	/* Ensure mas_find works with MA_UNDERFLOW */

	mas_set(&mas, 0);

	entry = mas_walk(&mas);

	mas_set(&mas, 0);

	mas_prev(&mas, 0);

	MT_BUG_ON(mt, mas.status != ma_underflow);

	MT_BUG_ON(mt, mas_find(&mas, ULONG_MAX) != entry);



	/* Restore active on mas_next */

	entry = mas_next(&mas, ULONG_MAX);

	index = mas.index;

	mas_prev(&mas, index);

	MT_BUG_ON(mt, mas.status != ma_underflow);

	MT_BUG_ON(mt, mas_next(&mas, ULONG_MAX) != entry);



	/* Ensure overflow -> active works */

	mas_prev(&mas, 0);

	mas_next(&mas, index - 1);

	MT_BUG_ON(mt, mas.status != ma_overflow);

	MT_BUG_ON(mt, mas_next(&mas, ULONG_MAX) != entry);



	mas_unlock(&mas);

}