[PATCH v3 06/48] maple_tree: Fix mas_prev() and mas_find() state handling

Liam Howlett
2023-01-17T02:34:52Z

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

Handle the MAS_NONE in mas_find() like a MAS_START.

Reported-by: syzbot+502859d610c661e56545@syzkaller.appspotmail.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
lib/maple_tree.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 03429149870c..667a4a46b024 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4855,7 +4855,7 @@ 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:
@@ -5924,6 +5924,7 @@ 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;
}

@@ -6014,6 +6015,9 @@ 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;
--
2.35.1