Subject: Re: [PATCH v5 perf,bpf 07/15] perf, bpf: save bpf_prog_info information as headers to perf.data

From: Jiri Olsa <[email-masked]>
Date: Mon, 4 Mar 2019 14:52:38 +0100

On Wed, Feb 27, 2019 at 09:06:35PM -0800, Song Liu wrote:

SNIP

> +static int process_bpf_prog_info(struct feat_fd *ff,
> +				 void *data __maybe_unused)
> +{
> +	struct bpf_prog_info_linear *info_linear;
> +	struct bpf_prog_info_node *info_node;
> +	struct perf_env *env = &ff->ph->env;
> +	u32 count, i;
> +	int err = -1;
> +
> +	if (do_read_u32(ff, &count))
> +		return -1;
> +
> +	down_write(&env->bpf_progs.lock);
> +
> +	for (i = 0; i < count; ++i) {
> +		u32 info_len, data_len;
> +
> +		info_linear = NULL;
> +		info_node = NULL;
> +		if (do_read_u32(ff, &info_len))
> +			goto out;
> +		if (do_read_u32(ff, &data_len))
> +			goto out;
> +
> +		if (info_len > sizeof(struct bpf_prog_info)) {
> +			pr_warning("detected invalid bpf_prog_info\n");
> +			goto out;
> +		}
> +
> +		info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
> +				     data_len);
> +		if (!info_linear)
> +			goto out;
> +		info_linear->info_len = sizeof(struct bpf_prog_info);
> +		info_linear->data_len = data_len;
> +		if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
> +			goto out;
> +		if (__do_read(ff, &info_linear->info, info_len))
> +			goto out;
> +		if (info_len < sizeof(struct bpf_prog_info))
> +			memset(((void *)(&info_linear->info)) + info_len, 0,
> +			       sizeof(struct bpf_prog_info) - info_len);
> +
> +		if (__do_read(ff, info_linear->data, data_len))
> +			goto out;
> +
> +		/* endian mismatch, drop the info, continue */
> +		if (ff->ph->needs_swap) {
> +			free(info_linear);
> +			continue;
> +		}

same here, please check this on the beginning
and add a warning message

thanks,
jrika

> +
> +		info_node = malloc(sizeof(struct bpf_prog_info_node));
> +		if (!info_node)
> +			goto out;
> +
> +		/* after reading from file, translate offset to address */
> +		bpf_program__bpil_offs_to_addr(info_linear);
> +		info_node->info_linear = info_linear;
> +		perf_env__insert_bpf_prog_info(env, info_node);
> +	}

SNIP