Re: [PATCH] perf session: Fix infinite loop on invalid perf.data file

[Ingo Molnar <mingo@kernel.org>]

* Namhyung Kim <namhyung@kernel.org> wrote:

> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -2753,6 +2753,15 @@ int perf_session__read_header(struct perf_session *session)
>  	if (perf_file_header__read(&f_header, header, fd) < 0)
>  		return -EINVAL;
>  
> +	/*
> +	 * Sanity check that perf.data was written cleanly; data size is
> +	 * initialized to 0 and updated only if the on_exit function is run.
> +	 * If data size is still 0 then the file contains only partial
> +	 * information.  Just warn user and process it as much as it can.
> +	 */
> +	if (f_header.data.size == 0)
> +		pr_warning("Data size is 0. Was the record command properly terminated?\n");

Just a detail: it would be nice to make all the user facing messages in 
tools/perf/util/header.c more specific and more structured. For example 
prefixing it with 'perf header:' would be fine:

	WARNING: perf/header: Data size is 0. Was the 'perf record' command properly terminated?

or something like that.

etc.

	Ingo