diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8339d81cba1db..675eb6d36e474 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -741,6 +741,17 @@ static int map_lookup_elem(union bpf_attr *attr) return err; } +static void maybe_wait_bpf_programs(struct bpf_map *map) +{ + /* Wait for any running BPF programs to complete so that + * userspace, when we return to it, knows that all programs + * that could be running use the new map value. + */ + if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS || + map->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS) + synchronize_rcu(); +} + #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags static int map_update_elem(union bpf_attr *attr) @@ -831,6 +842,7 @@ static int map_update_elem(union bpf_attr *attr) } __this_cpu_dec(bpf_prog_active); preempt_enable(); + maybe_wait_bpf_programs(map); out: free_value: kfree(value); @@ -883,6 +895,7 @@ static int map_delete_elem(union bpf_attr *attr) rcu_read_unlock(); __this_cpu_dec(bpf_prog_active); preempt_enable(); + maybe_wait_bpf_programs(map); out: kfree(key); err_put: