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

From: Hangbin Liu <haliu@redhat.com>
To: Paul Chaignon <paul@isovalent.com>
Cc: netdev@vger.kernel.org,
	Stephen Hemminger <stephen@networkplumber.org>,
	David Ahern <dsahern@gmail.com>
Subject: Re: [PATCH iproute2] lib/bpf: fix verbose flag when using libbpf
Date: Fri, 17 Dec 2021 15:15:31 +0800	[thread overview]
Message-ID: <Ybw5EwPCzZXeaWip@Laptop-X1> (raw)
In-Reply-To: <20211216153336.GA30454@Mem>

On Thu, Dec 16, 2021 at 04:33:36PM +0100, Paul Chaignon wrote:
> 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 <paul@isovalent.com>
> ---
>  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;
> +	}

nit: no need the curly braces when this is only 1 line

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

Thanks for the fixes.

Acked-by: Hangbin Liu <haliu@redhat.com>