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/maple_tree-fix-mas_empty_area-search.patch
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@xxxxxxxxxx>
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@xxxxxxxxxx
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reported-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx 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
