From f973fccd43d34b096077d5d21d051ef75b22a7ea Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Sat, 27 Apr 2024 20:09:53 -0700 Subject: [PATCH] libbpf: handle nulled-out program in struct_ops correctly If struct_ops has one of program callbacks set declaratively and host kernel is old and doesn't support this callback, libbpf will allow to load such struct_ops as long as that callback was explicitly nulled-out (presumably through skeleton). This is all working correctly, except we won't reset corresponding program slot to NULL before bailing out, which will lead to libbpf not detecting that BPF program has to be not auto-loaded. Fix this by unconditionally resetting corresponding program slot to NULL. Fixes: c911fc61a7ce ("libbpf: Skip zeroed or null fields if not found in the kernel type.") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240428030954.3918764-1-andrii@kernel.org Signed-off-by: Martin KaFai Lau --- tools/lib/bpf/libbpf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 97eb6e5dd7c8..898d5d34ecea 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1148,6 +1148,7 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map) * presented in the kernel BTF. */ if (libbpf_is_mem_zeroed(mdata, msize)) { + st_ops->progs[i] = NULL; pr_info("struct_ops %s: member %s not found in kernel, skipping it as it's set to zero\n", map->name, mname); continue;