Re: [PATCHv3 1/2] perf tools: Fix raw sample reading

David Ahern
2011-09-29T15:34:39Z

On 09/29/2011 09:05 AM, Jiri Olsa wrote:
> Wrong pointer is being passed for raw data sanity checking,
> when parsing sample event.
>
> This ends up with invalid event and perf record being stuck in
> __perf_session__process_events function during processing
> build IDs (process_buildids function).
>
> Following command hangs up in my setup:
> ./perf record -e raw_syscalls:sys_enter ls
>
> The fix is to use proper pointer to the raw data instead
> of the 'u' union.
>
> CC: David Ahern <dsahern@gmail.com>
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> ---
> tools/perf/util/evsel.c | 7 +++++--
> 1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index c5748c5..e389815 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -449,6 +449,8 @@ int perf_event__parse_sample(const union perf_event *event, u64 type,
> }
>
> if (type & PERF_SAMPLE_RAW) {
> + const u64 *pdata;
> +
> u.val64 = *array;
> if (WARN_ONCE(swapped,
> "Endianness of raw data not corrected!\n")) {
> @@ -462,11 +464,12 @@ int perf_event__parse_sample(const union perf_event *event, u64 type,
> return -EFAULT;
>
> data->raw_size = u.val32[0];
> + pdata = (void *) array + sizeof(u32);
>
> - if (sample_overlap(event, &u.val32[1], data->raw_size))
> + if (sample_overlap(event, pdata, data->raw_size))
> return -EFAULT;
>
> - data->raw_data = &u.val32[1];
> + data->raw_data = (void *) pdata;
> }
>
> return 0;

Oops. Thanks for fixing.

Reviewed-by: David Ahern <dsahern@gmail.com>