Re: [PATCH 1/2] [BUGFIX] perf probe: Fix --list option to show events only with uprobe events

[Namhyung Kim <namhyung@kernel.org>]

Hi Masami,

On Wed, 13 Aug 2014 00:50:55 +0000, Masami Hiramatsu wrote:
> +	if (kp_fd < 0 && up_fd < 0) {
> +		/* Both kprobes and uprobes are disabled, warn it. */
> +		if (kp_fd == -ENOTSUP && up_fd == -ENOTSUP)
> +			pr_warning("Debugfs is not mounted.\n");
> +		else if (kp_fd == -ENOENT && up_fd == -ENOENT)
> +			pr_warning("Please rebuild kernel with "
> +				   "CONFIG_KPROBE_EVENTS or/and "
> +				   "CONFIG_UPROBE_EVENTS.\n");
> +		else
> +			pr_warning("Failed to open kprobe events: %s.\n" \
> +				   "Failed to open uprobe events: %s.\n",
> +				   strerror(-kp_fd), strerror(-up_fd));

It seems the second strerror() might overwrite the message of the
first.  You'd better using strerror_r() IMHO.

Thanks,
Namhyung


> +		ret = kp_fd;
> +		goto out;
>  	}
>  
> +	if (up_fd >= 0) {
> +		ret = __show_perf_probe_events(up_fd, false);
> +		close(up_fd);
> +	}
> +out:
>  	exit_symbol_maps();
>  	return ret;
>  }