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| author | Liam Howlett <Liam.Howlett@oracle.com> | 2023-02-27 09:36:01 -0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-05 18:06:21 -0700 |
| commit | a7b92d59c885018cb7bb88539892278e4fd64b29 (patch) | |
| tree | f013678342bf7354e81d1640add97ea832e6e031 | |
| parent | 39d0bd86c499ecd6abae42a9b7112056c5560691 (diff) | |
| download | lwn-a7b92d59c885018cb7bb88539892278e4fd64b29.tar.gz lwn-a7b92d59c885018cb7bb88539892278e4fd64b29.zip | |
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>
| -rw-r--r-- | lib/maple_tree.c | 4 |
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; } |