From 50e81c82ad947045c7ed26ddc9acb17276b653b6 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Fri, 20 Jan 2023 11:26:04 -0500 Subject: maple_tree: reduce user error potential 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 Signed-off-by: Liam R. Howlett Signed-off-by: Andrew Morton --- lib/maple_tree.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'lib') diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 7e3cf5b7e68b..5804c5997598 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -4732,6 +4732,11 @@ static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit) 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; @@ -4838,6 +4843,11 @@ static inline void *mas_prev_entry(struct ma_state *mas, unsigned long min) { 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); -- cgit v1.2.3