6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> commit 29ad6bb313487370f9dfe5441fc8982593b6384e upstream. In the case of reverse allocation, mas->index and mas->last do not point to the correct allocation range, which will cause users to get incorrect allocation results, so fix it. If the user does not use it in a specific way, this bug will not be triggered. This is a bug, but only VMA uses it now, the way VMA is used now will not trigger it. There is a possibility that a user will trigger it in the future. Also re-check whether the size is still satisfied after the lower bound was increased, which is a corner case and is incorrect in previous versions. Link: https://lkml.kernel.org/r/20230419093625.99201-1-zhangpeng.00@xxxxxxxxxxxxx Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/maple_tree.c | 41 ++++++++++++++++++++--------------------- 1 file changed, 20 insertions(+), 21 deletions(-) --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5277,25 +5277,28 @@ static inline void mas_fill_gap(struct m * @size: The size of the gap * @fwd: Searching forward or back */ -static inline void mas_sparse_area(struct ma_state *mas, unsigned long min, +static inline int mas_sparse_area(struct ma_state *mas, unsigned long min, unsigned long max, unsigned long size, bool fwd) { - unsigned long start = 0; - - if (!unlikely(mas_is_none(mas))) - start++; + if (!unlikely(mas_is_none(mas)) && min == 0) { + min++; + /* + * At this time, min is increased, we need to recheck whether + * the size is satisfied. + */ + if (min > max || max - min + 1 < size) + return -EBUSY; + } /* mas_is_ptr */ - if (start < min) - start = min; - if (fwd) { - mas->index = start; - mas->last = start + size - 1; - return; + mas->index = min; + mas->last = min + size - 1; + } else { + mas->last = max; + mas->index = max - size + 1; } - - mas->index = max; + return 0; } /* @@ -5324,10 +5327,8 @@ int mas_empty_area(struct ma_state *mas, return -EBUSY; /* Empty set */ - if (mas_is_none(mas) || mas_is_ptr(mas)) { - mas_sparse_area(mas, min, max, size, true); - return 0; - } + if (mas_is_none(mas) || mas_is_ptr(mas)) + return mas_sparse_area(mas, min, max, size, true); /* The start of the window can only be within these values */ mas->index = min; @@ -5377,10 +5378,8 @@ int mas_empty_area_rev(struct ma_state * } /* Empty set. */ - if (mas_is_none(mas) || mas_is_ptr(mas)) { - mas_sparse_area(mas, min, max, size, false); - return 0; - } + if (mas_is_none(mas) || mas_is_ptr(mas)) + return mas_sparse_area(mas, min, max, size, false); /* The start of the window can only be within these values. */ mas->index = min;
