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, but BPF_F_RDONLY_PROG being set on a map during creation is invalid. Thus, ignore the BPF_F_RDONLY_PROG flag in the flags returned from get_map_info when checking for compatibility with an existing DEVMAP. The same problem is handled in a third-party ebpf library: - https://github.com/cilium/ebpf/issues/925 - https://github.com/cilium/ebpf/pull/930 Fixes: 0cdbb4b09a06 ("devmap: Allow map lookups from eBPF") Signed-off-by: Yureka Lilian <yuka@xxxxxxxx> --- tools/lib/bpf/libbpf.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index d41ee26b9..affcbb231 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5088,6 +5088,17 @@ 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, ignore the BPF_F_RDONLY_PROG flag in the flags + * returned from get_map_info 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_info.map_flags &= ~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 && -- 2.50.1
