Improve how we handle old BPF skeletons when it comes to BPF map
auto-attachment. Emit one warn-level message per each struct_ops map
that could have been auto-attached, if user provided recent enough BPF
skeleton version. Don't spam log if there are no relevant struct_ops
maps, though.
This should help users realize that they probably need to regenerate BPF
skeleton header with more recent bpftool/libbpf-cargo (or whatever other
means of BPF skeleton generation).
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
tools/lib/bpf/libbpf.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8625c948f60a..a3be6f8fac09 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -13967,32 +13967,34 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
*/
}
- /* Skeleton is created with earlier version of bpftool
- * which does not support auto-attachment
- */
- if (s->map_skel_sz < sizeof(struct bpf_map_skeleton))
- return 0;
for (i = 0; i < s->map_cnt; i++) {
struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz;
struct bpf_map *map = *map_skel->map;
- struct bpf_link **link = map_skel->link;
+ struct bpf_link **link;
if (!map->autocreate || !map->autoattach)
continue;
- if (*link)
- continue;
-
/* only struct_ops maps can be attached */
if (!bpf_map__is_struct_ops(map))
continue;
- *link = bpf_map__attach_struct_ops(map);
+ /* skeleton is created with earlier version of bpftool, notify user */
+ if (s->map_skel_sz < offsetofend(struct bpf_map_skeleton, link)) {
+ pr_warn("map '%s': BPF skeleton version is old, skipping map auto-attachment...\n",
+ bpf_map__name(map));
+ continue;
+ }
+
+ link = map_skel->link;
+ if (*link)
+ continue;
+
+ *link = bpf_map__attach_struct_ops(map);
if (!*link) {
err = -errno;
- pr_warn("map '%s': failed to auto-attach: %d\n",
- bpf_map__name(map), err);
+ pr_warn("map '%s': failed to auto-attach: %d\n", bpf_map__name(map), err);
return libbpf_err(err);
}
}
--
2.43.0
