Previously, re-using pinned DEVMAP maps would always fail, because get_map_info on a DEVMAP always returns flags with BPF_F_RDONLY_PROG set, it BPF_F_RDONLY_PROG being set on a map being created is invalid. Thus, match the BPF_F_RDONLY_PROG flag being set on the new map when checking for compatibility with an existing DEVMAP The same problem is handled in third-party ebpf library: - https://github.com/cilium/ebpf/issues/925 - https://github.com/cilium/ebpf/pull/930 Signed-off-by: Yureka Lilian --- tools/lib/bpf/libbpf.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index fb4d92c5c..a554d7fff 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5081,6 +5081,7 @@ static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) { struct bpf_map_info map_info; __u32 map_info_len = sizeof(map_info); + __u32 map_flags_for_check = map->def.map_flags; int err; memset(&map_info, 0, map_info_len); @@ -5093,11 +5094,20 @@ static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) return false; } + /* get_map_info on a DEVMAP will always return flags with + * BPF_F_RDONLY_PROG set, but it will never be set on a map + * being created. + * Thus, match the BPF_F_RDONLY_PROG flag being set on the new + * map when checking for compatibility with an existing DEVMAP + */ + if (map->def.type == BPF_MAP_TYPE_DEVMAP || map->def.type == BPF_MAP_TYPE_DEVMAP_HASH) + map_flags_for_check |= BPF_F_RDONLY_PROG; + return (map_info.type == map->def.type && map_info.key_size == map->def.key_size && map_info.value_size == map->def.value_size && map_info.max_entries == map->def.max_entries && - map_info.map_flags == map->def.map_flags && + map_info.map_flags == map_flags_for_check && map_info.map_extra == map->map_extra); } -- 2.50.1