From: Liam R. Howlett Liam.Howlett@oracle.com
commit 06e8fd999334bcd76b4d72d7b9206d4aea89764e upstream.
The internal function of mas_awalk() was incorrectly skipping the last entry in a node, which could potentially be NULL. This is only a problem for the left-most node in the tree - otherwise that NULL would not exist.
Fix mas_awalk() by using the metadata to obtain the end of the node for the loop and the logical pivot as apposed to the raw pivot value.
Link: https://lkml.kernel.org/r/20230414145728.4067069-2-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Liam.Howlett@oracle.com Reported-by: Rick Edgecombe rick.p.edgecombe@intel.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/maple_tree.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)
--- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5059,10 +5059,10 @@ static inline bool mas_anode_descend(str { enum maple_type type = mte_node_type(mas->node); unsigned long pivot, min, gap = 0; - unsigned char offset; - unsigned long *gaps; - unsigned long *pivots = ma_pivots(mas_mn(mas), type); - void __rcu **slots = ma_slots(mas_mn(mas), type); + unsigned char offset, data_end; + unsigned long *gaps, *pivots; + void __rcu **slots; + struct maple_node *node; bool found = false;
if (ma_is_dense(type)) { @@ -5070,13 +5070,15 @@ static inline bool mas_anode_descend(str return true; }
- gaps = ma_gaps(mte_to_node(mas->node), type); + node = mas_mn(mas); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + gaps = ma_gaps(node, type); offset = mas->offset; min = mas_safe_min(mas, pivots, offset); - for (; offset < mt_slots[type]; offset++) { - pivot = mas_safe_pivot(mas, pivots, offset, type); - if (offset && !pivot) - break; + data_end = ma_data_end(node, type, pivots, mas->max); + for (; offset <= data_end; offset++) { + pivot = mas_logical_pivot(mas, pivots, offset, type);
/* Not within lower bounds */ if (mas->index > pivot)