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-rw-r--r--tools/lib/bpf/btf.c22
1 files changed, 18 insertions, 4 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index ec92b87cae01..95db88b36cf3 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -4932,10 +4932,9 @@ static int btf_dedup_remap_types(struct btf_dedup *d)
*/
struct btf *btf__load_vmlinux_btf(void)
{
+ const char *sysfs_btf_path = "/sys/kernel/btf/vmlinux";
+ /* fall back locations, trying to find vmlinux on disk */
const char *locations[] = {
- /* try canonical vmlinux BTF through sysfs first */
- "/sys/kernel/btf/vmlinux",
- /* fall back to trying to find vmlinux on disk otherwise */
"/boot/vmlinux-%1$s",
"/lib/modules/%1$s/vmlinux-%1$s",
"/lib/modules/%1$s/build/vmlinux",
@@ -4949,8 +4948,23 @@ struct btf *btf__load_vmlinux_btf(void)
struct btf *btf;
int i, err;
- uname(&buf);
+ /* is canonical sysfs location accessible? */
+ if (faccessat(AT_FDCWD, sysfs_btf_path, F_OK, AT_EACCESS) < 0) {
+ pr_warn("kernel BTF is missing at '%s', was CONFIG_DEBUG_INFO_BTF enabled?\n",
+ sysfs_btf_path);
+ } else {
+ btf = btf__parse(sysfs_btf_path, NULL);
+ if (!btf) {
+ err = -errno;
+ pr_warn("failed to read kernel BTF from '%s': %d\n", sysfs_btf_path, err);
+ return libbpf_err_ptr(err);
+ }
+ pr_debug("loaded kernel BTF from '%s'\n", path);
+ return btf;
+ }
+ /* try fallback locations */
+ uname(&buf);
for (i = 0; i < ARRAY_SIZE(locations); i++) {
snprintf(path, PATH_MAX, locations[i], buf.release);