Messages in this thread Patch in this message | | | From | Jiasheng Jiang <> | Subject | [PATCH] seq_file: Fix potential addition overflow | Date | Mon, 25 Oct 2021 07:31:18 +0000 |
| |
After seq_hlist_start_percpu(), the value of &iter->li_cpu might be MAX_UINT. In that case, there will be addition overflow in the cpumask_next(). Therefore, it might be better to add the check before.
Fixes: 0bc7738 ("seq_file: add seq_list_*_percpu helpers") Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn> --- fs/seq_file.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/seq_file.c b/fs/seq_file.c index 5059248..f768c28 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -1105,6 +1105,9 @@ seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, if (node->next) return node->next; + if (*cpu >= nr_cpu_ids) + return NULL; + for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids; *cpu = cpumask_next(*cpu, cpu_possible_mask)) { struct hlist_head *bucket = per_cpu_ptr(head, *cpu); -- 2.7.4
| |