diff mbox series

[v2,02/33] maple_tree: Detect dead nodes in mas_start()

Message ID 20230127194110.533103-3-surenb@google.com (mailing list archive)
State New
Headers show
Series Per-VMA locks | expand

Commit Message

Suren Baghdasaryan Jan. 27, 2023, 7:40 p.m. UTC 
From: Liam Howlett <Liam.Howlett@oracle.com>

When initially starting a search, the root node may already be in the
process of being replaced in RCU mode.  Detect and restart the walk if
this is the case.  This is necessary for RCU mode of the maple tree.

Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 lib/maple_tree.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index e5eeecd14eee..482e17a460cb 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1353,12 +1353,16 @@  static inline struct maple_enode *mas_start(struct ma_state *mas)
 		mas->max = ULONG_MAX;
 		mas->depth = 0;
 
+retry:
 		root = mas_root(mas);
 		/* Tree with nodes */
 		if (likely(xa_is_node(root))) {
 			mas->depth = 1;
 			mas->node = mte_safe_root(root);
 			mas->offset = 0;
+			if (mte_dead_node(mas->node))
+				goto retry;
+
 			return NULL;
 		}