From 5327644614a18f5d0ff845844a4e9976210b3d8d Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 19 Feb 2020 22:26:35 -0800 Subject: [PATCH] libbpf: Relax check whether BTF is mandatory If BPF program is using BTF-defined maps, BTF is required only for libbpf itself to process map definitions. If after that BTF fails to be loaded into kernel (e.g., if it doesn't support BTF at all), this shouldn't prevent valid BPF program from loading. Existing retry-without-BTF logic for creating maps will succeed to create such maps without any problems. So, presence of .maps section shouldn't make BTF required for kernel. Update the check accordingly. Validated by ensuring simple BPF program with BTF-defined maps is still loaded on old kernel without BTF support and map is correctly parsed and created. Fixes: abd29c931459 ("libbpf: allow specifying map definitions using BTF") Reported-by: Julia Kartseva Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200220062635.1497872-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 514b1a5..0eb10b6 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2280,9 +2280,7 @@ static void bpf_object__sanitize_btf_ext(struct bpf_object *obj) static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj) { - return obj->efile.btf_maps_shndx >= 0 || - obj->efile.st_ops_shndx >= 0 || - obj->nr_extern > 0; + return obj->efile.st_ops_shndx >= 0 || obj->nr_extern > 0; } static int bpf_object__init_btf(struct bpf_object *obj, -- 2.7.4