The quilt patch titled Subject: maple_tree: add smp_rmb() to dead node detection has been removed from the -mm tree. Its filename was maple_tree-add-smp_rmb-to-dead-node-detection.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------ From: "Liam R. Howlett" Liam.Howlett@oracle.com Subject: maple_tree: add smp_rmb() to dead node detection Date: Mon, 27 Feb 2023 09:36:05 -0800

Add an smp_rmb() before reading the parent pointer to ensure that anything read from the node prior to the parent pointer hasn't been reordered ahead of this check.

The is necessary for RCU mode.

Link: https://lkml.kernel.org/r/20230227173632.3292573-7-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. 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 ---

lib/maple_tree.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/lib/maple_tree.c~maple_tree-add-smp_rmb-to-dead-node-detection +++ a/lib/maple_tree.c @@ -539,9 +539,11 @@ static inline struct maple_node *mte_par */ static inline bool ma_dead_node(const struct maple_node *node) { - struct maple_node *parent = (void *)((unsigned long) - node->parent & ~MAPLE_NODE_MASK); + struct maple_node *parent;

+ /* Do not reorder reads from the node prior to the parent check */ + smp_rmb(); + parent = (void *)((unsigned long) node->parent & ~MAPLE_NODE_MASK); return (parent == node); }

@@ -556,6 +558,8 @@ static inline bool mte_dead_node(const s struct maple_node *parent, *node;

node = mte_to_node(enode); + /* Do not reorder reads from the node prior to the parent check */ + smp_rmb(); parent = mte_parent(enode); return (parent == node); } _

Patches currently in -mm which might be from Liam.Howlett@oracle.com are