On Mon, Nov 28, 2022 at 09:59:00PM -0800, Andrii Nakryiko wrote:
On Sat, Nov 26, 2022 at 3:13 AM Changbin Du changbin.du@gmail.com wrote:
Show more information about why failed instead of just saying "No such file or directory".
Now will print below info: libbpf: can not find '.BTF' section libbpf: is CONFIG_DEBUG_INFO_BTF enabled for kernel? Error: failed to load BTF from /home/changbin/work/linux/vmlinux: No such file or directory
Signed-off-by: Changbin Du changbin.du@gmail.com
tools/lib/bpf/btf.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index d88647da2c7f..3f661d991808 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -906,6 +906,15 @@ struct btf *btf__new(const void *data, __u32 size) return libbpf_ptr(btf_new(data, size, NULL)); }
+static bool is_vmlinux(const char *path) +{
size_t path_len = strlen(path);size_t suffix_len = strlen("vmlinux");return (path_len >= suffix_len) &&(!memcmp(path + path_len - suffix_len, "vmlinux", suffix_len));+}
static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) { @@ -990,6 +999,9 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, err = 0;
if (!btf_data) {
pr_warn("can not find '%s' section\n", BTF_ELF_SEC);if (is_vmlinux(path))pr_warn("is CONFIG_DEBUG_INFO_BTF enabled for kernel?\n");this is generic piece of BTF loading code in libbpf, it knows nothing and should know nothing about vmlinux and CONFIG_DEBUG_INFO_BTF, this is not the right place to add such suggestions.
Check bpf_object__load_vmlinux_btf(), libbpf emits vmlinux-specific error there: "Error loading vmlinux BTF". If we need to mention CONFIG_DEBUG_INFO_BTF anywhere, that would be the place to do that.
Agreed. I think adding "can not find '.BTF' section" is enough to diagnose the problem. The standalone error msg "No such file or directory" is really weird.
err = -ENOENT; goto done; }-- 2.37.2