From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> commit 17dc622c7b0f94e49bed030726df4db12ecaa6b5 upstream. 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@xxxxxxxxxx Cc: <Stable@xxxxxxxxxxxxxxx> Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Reported-by: <syzbot+502859d610c661e56545@xxxxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/maple_tree.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -4844,7 +4844,7 @@ static inline void *mas_prev_entry(struc if (mas->index < min) { mas->index = mas->last = min; - mas_pause(mas); + mas->node = MAS_NONE; return NULL; } retry: @@ -5906,6 +5906,7 @@ void *mas_prev(struct ma_state *mas, uns if (!mas->index) { /* Nothing comes before 0 */ mas->last = 0; + mas->node = MAS_NONE; return NULL; } @@ -5996,6 +5997,9 @@ void *mas_find(struct ma_state *mas, uns 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;
