The patch titled
Subject: maple_tree: fix underflow in mas_spanning_rebalance()
has been added to the -mm mm-unstable branch. Its filename is
maple-tree-add-new-data-structure-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple-tree-add-new-data-structure-fix.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
Subject: maple_tree: fix underflow in mas_spanning_rebalance()
Date: Sat, 25 Jun 2022 00:39:06 +0000
When rebalancing a spanning store that spans the entire address space,
the big node end is not expanded the extra position that
mas_spanning_rebalance() expects. Fix this by expanding on such cases.
Also change mab_mas_cp() from assuming there are at least two entries to
ensure the correct metadata is written.
Link: https://lkml.kernel.org/r/20220625003854.1230114-2-Liam.Howlett@xxxxxxxxxx
Fixes: f8acc5e9581e (Maple Tree: add new data structure)
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reported-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/lib/maple_tree.c~maple-tree-add-new-data-structure-fix
+++ a/lib/maple_tree.c
@@ -1977,7 +1977,6 @@ static inline void mab_mas_cp(struct map
slots[mt_pivots[mt]] = NULL;
i = mab_start;
- pivots[j++] = b_node->pivot[i++];
do {
pivots[j++] = b_node->pivot[i++];
} while (i <= mab_end && likely(b_node->pivot[i]));
@@ -2970,7 +2969,7 @@ static int mas_spanning_rebalance(struct
mast->free = &free;
mast->destroy = &destroy;
l_mas.node = r_mas.node = m_mas.node = MAS_NONE;
- if (!mas_is_root_limits(mast->orig_l) &&
+ if (!(mast->orig_l->min && mast->orig_r->max == ULONG_MAX) &&
unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type]))
mast_spanning_rebalance(mast);
@@ -4004,6 +4003,9 @@ static inline int mas_wr_spanning_store(
if (r_mas.offset <= r_wr_mas.node_end)
mas_mab_cp(&r_mas, r_mas.offset, r_wr_mas.node_end,
&b_node, b_node.b_end + 1);
+ else
+ b_node.b_end++;
+
/* Stop spanning searches by searching for just index. */
l_mas.index = l_mas.last = mas->index;
_
Patches currently in -mm which might be from liam.howlett@xxxxxxxxxx are
maple-tree-add-new-data-structure-fix.patch
mm-mlock-drop-dead-code-in-count_mm_mlocked_page_nr.patch
