On Tue, Nov 15, 2022 at 06:36:25PM IST, Dan Carpenter wrote:
> [ Email screwup on my end means I have to resend two weeks of email.
> :/ -dan ]
>
> Hello Kumar Kartikeya Dwivedi,
>
> The patch db559117828d: "bpf: Consolidate spin_lock, timer management
> into btf_record" from Nov 4, 2022, leads to the following Smatch
> static checker warning:
>
> kernel/bpf/syscall.c:1002 map_check_btf()
> warn: ignoring unreachable code.
>
> kernel/bpf/syscall.c
> 946 static int map_check_btf(struct bpf_map *map, const struct btf *btf,
> 947 u32 btf_key_id, u32 btf_value_id)
> 948 {
> 949 const struct btf_type *key_type, *value_type;
> 950 u32 key_size, value_size;
> 951 int ret = 0;
> 952
> 953 /* Some maps allow key to be unspecified. */
> 954 if (btf_key_id) {
> 955 key_type = btf_type_id_size(btf, &btf_key_id, &key_size);
> 956 if (!key_type || key_size != map->key_size)
> 957 return -EINVAL;
> 958 } else {
> 959 key_type = btf_type_by_id(btf, 0);
> 960 if (!map->ops->map_check_btf)
> 961 return -EINVAL;
> 962 }
> 963
> 964 value_type = btf_type_id_size(btf, &btf_value_id, &value_size);
> 965 if (!value_type || value_size != map->value_size)
> 966 return -EINVAL;
> 967
> 968 map->record = btf_parse_fields(btf, value_type, BPF_SPIN_LOCK | BPF_TIMER | BPF_KPTR,
> 969 map->value_size);
> 970 if (!IS_ERR_OR_NULL(map->record)) {
> 971 int i;
> 972
> 973 if (!bpf_capable()) {
> 974 ret = -EPERM;
> 975 goto free_map_tab;
> 976 }
> 977 if (map->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG)) {
> 978 ret = -EACCES;
> 979 goto free_map_tab;
> 980 }
> 981 for (i = 0; i < sizeof(map->record->field_mask) * 8; i++) {
> 982 switch (map->record->field_mask & (1 << i)) {
> 983 case 0:
> 984 continue;
> 985 case BPF_SPIN_LOCK:
> 986 if (map->map_type != BPF_MAP_TYPE_HASH &&
> 987 map->map_type != BPF_MAP_TYPE_ARRAY &&
> 988 map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
> 989 map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
> 990 map->map_type != BPF_MAP_TYPE_INODE_STORAGE &&
> 991 map->map_type != BPF_MAP_TYPE_TASK_STORAGE &&
> 992 map->map_type != BPF_MAP_TYPE_CGRP_STORAGE) {
> 993 ret = -EOPNOTSUPP;
> 994 goto free_map_tab;
> 995 }
> 996 break;
> 997 case BPF_TIMER:
> 998 if (map->map_type != BPF_MAP_TYPE_HASH &&
> 999 map->map_type != BPF_MAP_TYPE_LRU_HASH &&
> 1000 map->map_type != BPF_MAP_TYPE_ARRAY) {
> 1001 return -EOPNOTSUPP;
> ^^^^^^^^^^^^^^^^^^^
> --> 1002 goto free_map_tab;
>
> s/return/ret =/
>
> Surprised the coverity-bot hasn't complained about this...
>
Thanks, another bad gaffe :/. Fixed locally, will push it out with v8.
