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From:   "Liam R. Howlett" <Liam.Howlett@oracle.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org
Cc:     maple-tree@lists.infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        "Liam R. Howlett" <Liam.Howlett@Oracle.com>,
        Stable@vger.kernel.org,
        "Liam R . Howlett" <Liam.Howlett@oracle.com>
Subject: [PATCH 6.1 02/14] maple_tree: fix potential rcu issue
Date:   Tue, 11 Apr 2023 11:10:43 -0400
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From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>

commit 65be6f058b0eba98dc6c6f197ea9f62c9b6a519f upstream.

Ensure the node isn't dead after reading the node end.

Link: https://lkml.kernel.org/r/20230120162650.984577-3-Liam.Howlett@oracle.com
Cc: <Stable@vger.kernel.org>
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 lib/maple_tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index fd824b065ace..1ade7748cc9b 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4656,13 +4656,13 @@ static inline void *mas_next_nentry(struct ma_state *mas,
 	pivots = ma_pivots(node, type);
 	slots = ma_slots(node, type);
 	mas->index = mas_safe_min(mas, pivots, mas->offset);
+	count = ma_data_end(node, type, pivots, mas->max);
 	if (ma_dead_node(node))
 		return NULL;
 
 	if (mas->index > max)
 		return NULL;
 
-	count = ma_data_end(node, type, pivots, mas->max);
 	if (mas->offset > count)
 		return NULL;
 
-- 
2.39.2