The patch titled Subject: maple_tree: fix mas_empty_area() search has been added to the -mm mm-hotfixes-unstable branch. Its filename is maple_tree-fix-mas_empty_area-search.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: "Liam R. Howlett" Liam.Howlett@oracle.com Subject: maple_tree: fix mas_empty_area() search Date: Fri, 14 Apr 2023 10:57:27 -0400
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 ---
lib/maple_tree.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)
--- a/lib/maple_tree.c~maple_tree-fix-mas_empty_area-search +++ a/lib/maple_tree.c @@ -5056,10 +5056,10 @@ 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)) { @@ -5067,13 +5067,15 @@ 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) _
Patches currently in -mm which might be from Liam.Howlett@oracle.com are
mm-mprotect-fix-do_mprotect_pkey-return-on-error.patch mm-mempolicy-fix-use-after-free-of-vma-iterator.patch maple_tree-make-maple-state-reusable-after-mas_empty_area_rev.patch maple_tree-fix-mas_empty_area-search.patch mm-mmap-regression-fix-for-unmapped_area_topdown.patch