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authorLiam Howlett <Liam.Howlett@oracle.com>2023-02-27 09:36:01 -0800
committerAndrew Morton <akpm@linux-foundation.org>2023-04-05 18:06:21 -0700
commita7b92d59c885018cb7bb88539892278e4fd64b29 (patch)
treef013678342bf7354e81d1640add97ea832e6e031 /lib
parent39d0bd86c499ecd6abae42a9b7112056c5560691 (diff)
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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. Link: https://lkml.kernel.org/r/20230227173632.3292573-3-surenb@google.com 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> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/maple_tree.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 095b9cb1f4f1..3d53339656e1 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1360,12 +1360,16 @@ 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;
}