From 0d6ead6d985507fafac61abaa3c5ef20a76f1add Mon Sep 17 00:00:00 2001 From: Liam Howlett Date: Thu, 24 Nov 2022 10:48:23 -0500 Subject: [PATCH] maple_tree: Detect dead nodes in mas_start() 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 --- lib/maple_tree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 4c7b1bcdd24cb..548fed5212bcd 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -1354,11 +1354,15 @@ static inline struct maple_enode *mas_start(struct ma_state *mas) mas->depth = 0; mas->offset = 0; +retry: root = mas_root(mas); /* Tree with nodes */ if (likely(xa_is_node(root))) { mas->depth = 1; mas->node = mte_safe_root(root); + if (mte_dead_node(mas->node)) + goto retry; + return NULL; } -- 2.50.1