From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Fri, 20 Jan 2023 16:26:07 +0000 (-0500)
Subject: maple_tree: fix mas_prev() and mas_find() state handling
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=17dc622c7b0f94e49bed030726df4db12ecaa6b5;p=linux.git

maple_tree: fix mas_prev() and mas_find() state handling

When mas_prev() does not find anything, set the state to MAS_NONE.

Handle the MAS_NONE in mas_find() like a MAS_START.

Link: https://lkml.kernel.org/r/20230120162650.984577-7-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: <syzbot+502859d610c661e56545@syzkaller.appspotmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 7c786bd5e575a..5e97031892590 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4845,7 +4845,7 @@ static inline void *mas_prev_entry(struct ma_state *mas, unsigned long min)
 
 	if (mas->index < min) {
 		mas->index = mas->last = min;
-		mas_pause(mas);
+		mas->node = MAS_NONE;
 		return NULL;
 	}
 retry:
@@ -5919,6 +5919,7 @@ void *mas_prev(struct ma_state *mas, unsigned long min)
 	if (!mas->index) {
 		/* Nothing comes before 0 */
 		mas->last = 0;
+		mas->node = MAS_NONE;
 		return NULL;
 	}
 
@@ -6009,6 +6010,9 @@ void *mas_find(struct ma_state *mas, unsigned long max)
 		mas->index = ++mas->last;
 	}
 
+	if (unlikely(mas_is_none(mas)))
+		mas->node = MAS_START;
+
 	if (unlikely(mas_is_start(mas))) {
 		/* First run or continue */
 		void *entry;