* David Ahern <dsah...@gmail.com> wrote:
> On 5/7/13 12:29 AM, Ingo Molnar wrote:
> >
> >* Stephane Eranian <eran...@google.com> wrote:
> >
> >>This is a good fix. I have run into this infinite loop in perf report
> >>many times.
> >
> >Hm, perf record should really not assume much about the perf.data and
> >should avoid infinite loops ...
> >
> >So while making perf.data more consistent on SIGTERM is a nice fix, perf
> >report should be fixed as well to detect loops and such.
> >
> >Thanks,
> >
> > Ingo
> >
>
> This seems to do the trick:
>
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 326068a..e82646f 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -2802,6 +2802,17 @@ int perf_session__read_header(struct
> perf_session *session, int fd)
> 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 cannot be
> + * processed.
> + */
> + if (f_header.data.size == 0) {
> + pr_err("data size is 0. Was record properly terminated?\n");
> + return -1;
> + }
Hm, this detects the condition - but where does the looping come from?
Can it happen with a perf.data that 'seems' clean but is corrupted
(because not fully written, buggy kernel just crashed, etc.).
In essence it would be _very_ nice if someone reproduced the looping and
checked what to do to fix the looping itself. Or does the above
data.size == 0 check fully fix the looping under every possible state of a
perf.data?
Thanks,
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
