netdev - Re: [PATCH net-next] selftests/bpf: check the instruction dumps are populated

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Date:   Mon, 28 Aug 2017 10:19:23 -0700
From:   Martin KaFai Lau <kafai@...com>
To:     Jakub Kicinski <jakub.kicinski@...ronome.com>
CC:     <netdev@...r.kernel.org>, <daniel@...earbox.net>,
        <oss-drivers@...ronome.com>
Subject: Re: [PATCH net-next] selftests/bpf: check the instruction dumps are
 populated

On Fri, Aug 25, 2017 at 02:39:57PM -0700, Jakub Kicinski wrote:
> Add a basic test for checking whether kernel is populating
> the jited and xlated BPF images.  It was used to confirm
> the behaviour change from commit d777b2ddbecf ("bpf: don't
> zero out the info struct in bpf_obj_get_info_by_fd()"),
> which made bpf_obj_get_info_by_fd() usable for retrieving
> the image dumps.
Acked-by: Martin KaFai Lau <kafai@...com>

>
> Signed-off-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
> ---
>  tools/testing/selftests/bpf/test_progs.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
> index 1cb037803679..11ee25cea227 100644
> --- a/tools/testing/selftests/bpf/test_progs.c
> +++ b/tools/testing/selftests/bpf/test_progs.c
> @@ -279,7 +279,7 @@ static void test_bpf_obj_id(void)
>  	/* +1 to test for the info_len returned by kernel */
>  	struct bpf_prog_info prog_infos[nr_iters + 1];
>  	struct bpf_map_info map_infos[nr_iters + 1];
> -	char jited_insns[128], xlated_insns[128];
> +	char jited_insns[128], xlated_insns[128], zeros[128];
>  	__u32 i, next_id, info_len, nr_id_found, duration = 0;
>  	int sysctl_fd, jit_enabled = 0, err = 0;
>  	__u64 array_value;
> @@ -305,6 +305,7 @@ static void test_bpf_obj_id(void)
>  		objs[i] = NULL;
>
>  	/* Check bpf_obj_get_info_by_fd() */
> +	bzero(zeros, sizeof(zeros));
>  	for (i = 0; i < nr_iters; i++) {
>  		err = bpf_prog_load(file, BPF_PROG_TYPE_SOCKET_FILTER,
>  				    &objs[i], &prog_fds[i]);
> @@ -318,6 +319,8 @@ static void test_bpf_obj_id(void)
>  		/* Check getting prog info */
>  		info_len = sizeof(struct bpf_prog_info) * 2;
>  		bzero(&prog_infos[i], info_len);
> +		bzero(jited_insns, sizeof(jited_insns));
> +		bzero(xlated_insns, sizeof(xlated_insns));
>  		prog_infos[i].jited_prog_insns = ptr_to_u64(jited_insns);
>  		prog_infos[i].jited_prog_len = sizeof(jited_insns);
>  		prog_infos[i].xlated_prog_insns = ptr_to_u64(xlated_insns);
> @@ -328,15 +331,20 @@ static void test_bpf_obj_id(void)
>  			  prog_infos[i].type != BPF_PROG_TYPE_SOCKET_FILTER ||
>  			  info_len != sizeof(struct bpf_prog_info) ||
>  			  (jit_enabled && !prog_infos[i].jited_prog_len) ||
> -			  !prog_infos[i].xlated_prog_len,
> +			  (jit_enabled &&
> +			   !memcmp(jited_insns, zeros, sizeof(zeros))) ||
> +			  !prog_infos[i].xlated_prog_len ||
> +			  !memcmp(xlated_insns, zeros, sizeof(zeros)),
>  			  "get-prog-info(fd)",
> -			  "err %d errno %d i %d type %d(%d) info_len %u(%lu) jit_enabled %d jited_prog_len %u xlated_prog_len %u\n",
> +			  "err %d errno %d i %d type %d(%d) info_len %u(%lu) jit_enabled %d jited_prog_len %u xlated_prog_len %u jited_prog %d xlated_prog %d\n",
>  			  err, errno, i,
>  			  prog_infos[i].type, BPF_PROG_TYPE_SOCKET_FILTER,
>  			  info_len, sizeof(struct bpf_prog_info),
>  			  jit_enabled,
>  			  prog_infos[i].jited_prog_len,
> -			  prog_infos[i].xlated_prog_len))
> +			  prog_infos[i].xlated_prog_len,
> +			  !!memcmp(jited_insns, zeros, sizeof(zeros)),
> +			  !!memcmp(xlated_insns, zeros, sizeof(zeros))))
>  			goto done;
>
>  		map_fds[i] = bpf_find_map(__func__, objs[i], "test_map_id");
> --
> 2.11.0
>