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authorLiam R. Howlett <Liam.Howlett@Oracle.com>2023-04-11 18:10:50 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-04-13 17:55:39 +0300
commit5f7c59126498f25959f81bd533af441f14ad7888 (patch)
treed3386d077925f34852b825355a8404f72b2cb3af /lib
parent3825e4495bccba46ec447d8444456d1fe5824580 (diff)
downloadlinux-5f7c59126498f25959f81bd533af441f14ad7888.tar.xz
maple_tree: detect dead nodes in mas_start()
commit a7b92d59c885018cb7bb88539892278e4fd64b29 upstream. 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 Cc: <Stable@vger.kernel.org> Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam Howlett <Liam.Howlett@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 54484bd756e5..6b451a432738 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1352,12 +1352,16 @@ 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;
}