From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Tue, 11 Apr 2023 15:10:43 +0000 (-0400)
Subject: maple_tree: fix potential rcu issue
X-Git-Tag: v6.2.11~12
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d478ff0ca89f06c36d9fe45654ddf76d768ac8e7;p=thirdparty%2Fkernel%2Fstable.git

maple_tree: fix potential rcu issue

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 0b8353c6ee8ed..e0a76f6368e4e 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4655,13 +4655,13 @@ 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;