Patch "maple_tree: reduce user error potential" has been added to the 6.2-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    maple_tree: reduce user error potential

to the 6.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     maple_tree-reduce-user-error-potential.patch
and it can be found in the queue-6.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable-owner@vger.kernel.org Tue Apr 11 17:12:40 2023
From: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Date: Tue, 11 Apr 2023 11:10:44 -0400
Subject: maple_tree: reduce user error potential
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, stable@vger.kernel.org
Cc: maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Liam R. Howlett" <Liam.Howlett@Oracle.com>, Stable@vger.kernel.org, "Liam R . Howlett" <Liam.Howlett@oracle.com>
Message-ID: <20230411151055.2910579-4-Liam.Howlett@oracle.com>

From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>

commit 50e81c82ad947045c7ed26ddc9acb17276b653b6 upstream.

When iterating, a user may operate on the tree and cause the maple state
to be altered and left in an unintuitive state.  Detect this scenario and
correct it by setting to the limit and invalidating the state.

Link: https://lkml.kernel.org/r/20230120162650.984577-4-Liam.Howlett@oracle.com
Cc: <Stable@vger.kernel.org>
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/maple_tree.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4736,6 +4736,11 @@ static inline void *mas_next_entry(struc
 	unsigned long last;
 	enum maple_type mt;
 
+	if (mas->index > limit) {
+		mas->index = mas->last = limit;
+		mas_pause(mas);
+		return NULL;
+	}
 	last = mas->last;
 retry:
 	offset = mas->offset;
@@ -4842,6 +4847,11 @@ static inline void *mas_prev_entry(struc
 {
 	void *entry;
 
+	if (mas->index < min) {
+		mas->index = mas->last = min;
+		mas_pause(mas);
+		return NULL;
+	}
 retry:
 	while (likely(!mas_is_none(mas))) {
 		entry = mas_prev_nentry(mas, min, mas->index);


Patches currently in stable-queue which might be from stable-owner@vger.kernel.org are

queue-6.2/maple_tree-fix-potential-rcu-issue.patch
queue-6.2/maple_tree-add-smp_rmb-to-dead-node-detection.patch
queue-6.2/maple_tree-add-rcu-lock-checking-to-rcu-callback-functions.patch
queue-6.2/maple_tree-fix-handle-of-invalidated-state-in-mas_wr_store_setup.patch
queue-6.2/maple_tree-reduce-user-error-potential.patch
queue-6.2/maple_tree-fix-mas_prev-and-mas_find-state-handling.patch
queue-6.2/maple_tree-remove-gfp_zero-from-kmem_cache_alloc-and-kmem_cache_alloc_bulk.patch
queue-6.2/maple_tree-be-more-cautious-about-dead-nodes.patch
queue-6.2/mm-enable-maple-tree-rcu-mode-by-default.patch
queue-6.2/maple_tree-detect-dead-nodes-in-mas_start.patch
queue-6.2/maple_tree-fix-freeing-of-nodes-in-rcu-mode.patch
queue-6.2/maple_tree-remove-extra-smp_wmb-from-mas_dead_leaves.patch
queue-6.2/maple_tree-refine-ma_state-init-from-mas_start.patch