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@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> --- This should come before 9df3d25a97ec ("mm: expand vma iterator interface") in the mm-unstable branch. 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 7d3131ecd5f8..19d272ee4b78 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -4844,7 +4844,7 @@ 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: @@ -5917,6 +5917,7 @@ 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; } @@ -6007,6 +6008,9 @@ 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