From a459f4bb27f2e2730039c57786b82288742c8c74 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 8 Jul 2024 13:45:40 -0700 Subject: libbpf: improve old BPF skeleton handling for map auto-attach 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 Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20240708204540.4188946-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/libbpf.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) (limited to 'tools/lib') 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); } } -- cgit v1.2.3-58-ga151