From: "Liam R. Howlett" Liam.Howlett@Oracle.com
commit 39d0bd86c499ecd6abae42a9b7112056c5560691 upstream.
ma_pivots() and ma_data_end() may be called with a dead node. Ensure to that the node isn't dead before using the returned values.
This is necessary for RCU mode of the maple tree.
Link: https://lkml.kernel.org/r/20230227173632.3292573-1-surenb@google.com Link: https://lkml.kernel.org/r/20230227173632.3292573-2-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Cc: Stable@vger.kernel.org Signed-off-by: Liam Howlett Liam.Howlett@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/maple_tree.c | 52 +++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 9 deletions(-)
--- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -534,6 +534,7 @@ static inline bool ma_dead_node(const st
return (parent == node); } + /* * mte_dead_node() - check if the @enode is dead. * @enode: The encoded maple node @@ -615,6 +616,8 @@ static inline unsigned int mas_alloc_req * @node - the maple node * @type - the node type * + * In the event of a dead node, this array may be %NULL + * * Return: A pointer to the maple node pivots */ static inline unsigned long *ma_pivots(struct maple_node *node, @@ -1086,8 +1089,11 @@ static int mas_ascend(struct ma_state *m a_type = mas_parent_enum(mas, p_enode); a_node = mte_parent(p_enode); a_slot = mte_parent_slot(p_enode); - pivots = ma_pivots(a_node, a_type); a_enode = mt_mk_node(a_node, a_type); + pivots = ma_pivots(a_node, a_type); + + if (unlikely(ma_dead_node(a_node))) + return 1;
if (!set_min && a_slot) { set_min = true; @@ -1393,6 +1399,9 @@ static inline unsigned char ma_data_end( { unsigned char offset;
+ if (!pivots) + return 0; + if (type == maple_arange_64) return ma_meta_end(node, type);
@@ -1428,6 +1437,9 @@ static inline unsigned char mas_data_end return ma_meta_end(node, type);
pivots = ma_pivots(node, type); + if (unlikely(ma_dead_node(node))) + return 0; + offset = mt_pivots[type] - 1; if (likely(!pivots[offset])) return ma_meta_end(node, type); @@ -4493,6 +4505,9 @@ static inline int mas_prev_node(struct m node = mas_mn(mas); slots = ma_slots(node, mt); pivots = ma_pivots(node, mt); + if (unlikely(ma_dead_node(node))) + return 1; + mas->max = pivots[offset]; if (offset) mas->min = pivots[offset - 1] + 1; @@ -4514,6 +4529,9 @@ static inline int mas_prev_node(struct m slots = ma_slots(node, mt); pivots = ma_pivots(node, mt); offset = ma_data_end(node, mt, pivots, mas->max); + if (unlikely(ma_dead_node(node))) + return 1; + if (offset) mas->min = pivots[offset - 1] + 1;
@@ -4562,6 +4580,7 @@ static inline int mas_next_node(struct m struct maple_enode *enode; int level = 0; unsigned char offset; + unsigned char node_end; enum maple_type mt; void __rcu **slots;
@@ -4585,7 +4604,11 @@ static inline int mas_next_node(struct m node = mas_mn(mas); mt = mte_node_type(mas->node); pivots = ma_pivots(node, mt); - } while (unlikely(offset == ma_data_end(node, mt, pivots, mas->max))); + node_end = ma_data_end(node, mt, pivots, mas->max); + if (unlikely(ma_dead_node(node))) + return 1; + + } while (unlikely(offset == node_end));
slots = ma_slots(node, mt); pivot = mas_safe_pivot(mas, pivots, ++offset, mt); @@ -4601,6 +4624,9 @@ static inline int mas_next_node(struct m mt = mte_node_type(mas->node); slots = ma_slots(node, mt); pivots = ma_pivots(node, mt); + if (unlikely(ma_dead_node(node))) + return 1; + offset = 0; pivot = pivots[0]; } @@ -4647,11 +4673,14 @@ static inline void *mas_next_nentry(stru return NULL; }
- pivots = ma_pivots(node, type); slots = ma_slots(node, type); - mas->index = mas_safe_min(mas, pivots, mas->offset); + pivots = ma_pivots(node, type); count = ma_data_end(node, type, pivots, mas->max); - if (ma_dead_node(node)) + if (unlikely(ma_dead_node(node))) + return NULL; + + mas->index = mas_safe_min(mas, pivots, mas->offset); + if (unlikely(ma_dead_node(node))) return NULL;
if (mas->index > max) @@ -4809,6 +4838,11 @@ retry:
slots = ma_slots(mn, mt); pivots = ma_pivots(mn, mt); + if (unlikely(ma_dead_node(mn))) { + mas_rewalk(mas, index); + goto retry; + } + if (offset == mt_pivots[mt]) pivot = mas->max; else @@ -6611,11 +6645,11 @@ static inline void *mas_first_entry(stru while (likely(!ma_is_leaf(mt))) { MT_BUG_ON(mas->tree, mte_dead_node(mas->node)); slots = ma_slots(mn, mt); - pivots = ma_pivots(mn, mt); - max = pivots[0]; entry = mas_slot(mas, slots, 0); + pivots = ma_pivots(mn, mt); if (unlikely(ma_dead_node(mn))) return NULL; + max = pivots[0]; mas->node = entry; mn = mas_mn(mas); mt = mte_node_type(mas->node); @@ -6635,13 +6669,13 @@ static inline void *mas_first_entry(stru if (likely(entry)) return entry;
- pivots = ma_pivots(mn, mt); - mas->index = pivots[0] + 1; mas->offset = 1; entry = mas_slot(mas, slots, 1); + pivots = ma_pivots(mn, mt); if (unlikely(ma_dead_node(mn))) return NULL;
+ mas->index = pivots[0] + 1; if (mas->index > limit) goto none;