[PATCH iproute2] lib/bpf: fix verbose flag when using libbpf

Since commit 6d61a2b55799 ("lib: add libbpf support"), passing the
verbose flag to tc filter doesn't dump the verifier logs anymore in case
of successful loading.

This commit fixes it by setting the log_level attribute before loading.
To that end, we need to call bpf_object__load_xattr directly instead of
relying on bpf_object__load.

Fixes: 6d61a2b55799 ("lib: add libbpf support")
Signed-off-by: Paul Chaignon <redacted>
---
 lib/bpf_libbpf.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/bpf_libbpf.c b/lib/bpf_libbpf.c
index dbec2cb5..b992a62c 100644
--- a/lib/bpf_libbpf.c
+++ b/lib/bpf_libbpf.c

@@ -246,6 +246,7 @@ static int handle_legacy_maps(struct bpf_object *obj)
 
 static int load_bpf_object(struct bpf_cfg_in *cfg)
 {
+	struct bpf_object_load_attr attr = {};
 	struct bpf_program *p, *prog = NULL;
 	struct bpf_object *obj;
 	char root_path[PATH_MAX];

@@ -302,7 +303,11 @@ static int load_bpf_object(struct bpf_cfg_in *cfg)
 	if (ret)
 		goto unload_obj;
 
-	ret = bpf_object__load(obj);
+	attr.obj = obj;
+	if (cfg->verbose) {
+		attr.log_level = 2;
+	}

+	ret = bpf_object__load_xattr(&attr);
 	if (ret)
 		goto unload_obj;