[PATCH Fix 0/2] maple_tree: mas_spanning_rebalance() patches

[PATCH Fix 0/2] maple_tree: mas_spanning_rebalance() patches

[Liam Howlett]

Andrew,

Please apply these to the maple tree series after the indicated 'fixes'
patches.  This fixes a soft lockup reported by Yu and adds a testcase to
the test_maple_tree suite.

Thanks,
Liam

Liam R. Howlett (2):
  maple_tree: Fix mas_spanning_rebalance() corner case
  test_maple_tree: Add test for spanning store to most of the tree

 lib/maple_tree.c      |  5 +++--
 lib/test_maple_tree.c | 10 +++++++++-
 2 files changed, 12 insertions(+), 3 deletions(-)

-- 
2.35.1

[PATCH Fix 1/2] maple_tree: Fix mas_spanning_rebalance() corner case

[Liam Howlett]

When a node is insufficient during a spanning rebalance loop and
mast_spanning_rebalance() is called to combine neighbouring nodes, the
loop should not terminate regardless of if neighbours exist or not.
This will allow the data to be stored in the correct node.

Reported-by: Yu Zhao <yuzhao@google.com>
Fixes: 37a4d714b7d9 (maple_tree: fix underflow in mas_spanning_rebalance())
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 lib/maple_tree.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index d8457122ca5d..2cccd8f2153f 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3029,8 +3029,7 @@ static int mas_spanning_rebalance(struct ma_state *mas,
 		if (mas_is_root_limits(mast->orig_l))
 			break;
 
-		if (!mast_spanning_rebalance(mast))
-			break;
+		mast_spanning_rebalance(mast);
 
 		/* rebalancing from other nodes may require another loop. */
 		if (!count)
@@ -6521,6 +6520,7 @@ static inline void *mas_first_entry(struct ma_state *mas, struct maple_node *mn,
 	max = mas->max;
 	mas->offset = 0;
 	while (likely(!ma_is_leaf(mt))) {
+		MT_BUG_ON(mas->tree, mte_dead_node(mas->node));
 		slots = ma_slots(mn, mt);
 		pivots = ma_pivots(mn, mt);
 		max = pivots[0];
@@ -6531,6 +6531,7 @@ static inline void *mas_first_entry(struct ma_state *mas, struct maple_node *mn,
 		mn = mas_mn(mas);
 		mt = mte_node_type(mas->node);
 	}
+	MT_BUG_ON(mas->tree, mte_dead_node(mas->node));
 
 	mas->max = max;
 	slots = ma_slots(mn, mt);
-- 
2.35.1

[PATCH Fix 2/2] test_maple_tree: Add test for spanning store to most of the tree

[Liam Howlett]

Test spanning almost the entire tree to detect if the root is dead and
the node is placed in the wrong location.

Fixes: 1d3ae73e4e86 (test_maple_tree: Add test for spanning store to most of the tree)
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 lib/test_maple_tree.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index 8de5705b7b9b..b028f5648857 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -35685,7 +35685,6 @@ static noinline void check_spanning_write(struct maple_tree *mt)
 	mas_set(&mas, 1205);
 	MT_BUG_ON(mt, mas_walk(&mas) != NULL);
 	mtree_unlock(mt);
-	mt_dump(mt);
 	mt_validate(mt);
 	mtree_destroy(mt);
 
@@ -35817,6 +35816,15 @@ static noinline void check_spanning_write(struct maple_tree *mt)
 	MT_BUG_ON(mt, mas_walk(&mas) != NULL);
 	mtree_unlock(mt);
 	mtree_destroy(mt);
+
+	mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE);
+	for (i = 0; i <= 100; i++)
+		mtree_test_store_range(mt, i * 10, i * 10 + 5, &i);
+
+	mtree_lock(mt);
+	mas_set_range(&mas, 76, 875);
+	mas_store_gfp(&mas, NULL, GFP_KERNEL);
+	mtree_unlock(mt);
 }
 
 static noinline void check_null_expand(struct maple_tree *mt)
-- 
2.35.1