diff mbox series

[v2,03/44] maple_tree: Reduce user error potential

Message ID 20230105191517.3099082-4-Liam.Howlett@oracle.com
State New
Headers
Series VMA tree type safety and remove __vma_adjust() |

Commit Message

Liam R. Howlett Jan. 5, 2023, 7:15 p.m. UTC 
  From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>

When iterating, a user may operate on the tree and cause the maple state
to be altered and left in an unintuitive state.  Detect this scenario
and correct it by setting to the limit and invalidating the state.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 lib/maple_tree.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index f3c5ad9ff57f..14cff87cf058 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4742,6 +4742,11 @@  static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit)
 	unsigned long last;
 	enum maple_type mt;
 
+	if (mas->index > limit) {
+		mas->index = mas->last = limit;
+		mas_pause(mas);
+		return NULL;
+	}
 	last = mas->last;
 retry:
 	offset = mas->offset;
@@ -4848,6 +4853,11 @@  static inline void *mas_prev_entry(struct ma_state *mas, unsigned long min)
 {
 	void *entry;
 
+	if (mas->index < min) {
+		mas->index = mas->last = min;
+		mas_pause(mas);
+		return NULL;
+	}
 retry:
 	while (likely(!mas_is_none(mas))) {
 		entry = mas_prev_nentry(mas, min, mas->index);