+ maple-tree-add-new-data-structure-fix-2.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: maple_tree: fix mas_spanning_rebalance() corner case
has been added to the -mm mm-unstable branch.  Its filename is
     maple-tree-add-new-data-structure-fix-2.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-2.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@oracle.com>
Subject: maple_tree: fix mas_spanning_rebalance() corner case
Date: Wed, 29 Jun 2022 15:23:50 +0000

When a node is insufficient during a spanning rebalance loop and
mast_spanning_rebalance() is called to combine neighbouring nodes, the
loop should not terminate regardless of if neighbours exist or not.  This
will allow the data to be stored in the correct node.

Link: https://lkml.kernel.org/r/20220629152340.3451959-2-Liam.Howlett@oracle.com
Fixes: 37a4d714b7d9 (maple_tree: fix underflow in mas_spanning_rebalance())
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/maple_tree.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/lib/maple_tree.c~maple-tree-add-new-data-structure-fix-2
+++ a/lib/maple_tree.c
@@ -3029,8 +3029,7 @@ static int mas_spanning_rebalance(struct
 		if (mas_is_root_limits(mast->orig_l))
 			break;
 
-		if (!mast_spanning_rebalance(mast))
-			break;
+		mast_spanning_rebalance(mast);
 
 		/* rebalancing from other nodes may require another loop. */
 		if (!count)
@@ -6521,6 +6520,7 @@ static inline void *mas_first_entry(stru
 	max = mas->max;
 	mas->offset = 0;
 	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];
@@ -6531,6 +6531,7 @@ static inline void *mas_first_entry(stru
 		mn = mas_mn(mas);
 		mt = mte_node_type(mas->node);
 	}
+	MT_BUG_ON(mas->tree, mte_dead_node(mas->node));
 
 	mas->max = max;
 	slots = ma_slots(mn, mt);
_

Patches currently in -mm which might be from liam.howlett@oracle.com are

android-binder-fix-lockdep-check-on-clearing-vma.patch
maple-tree-add-new-data-structure-fix.patch
maple-tree-add-new-data-structure-fix-2.patch
lib-test_maple_tree-add-testing-for-maple-tree-fix.patch
mm-mlock-drop-dead-code-in-count_mm_mlocked_page_nr.patch