On Tue, Jan 19, 2021 at 12:38:20PM -0800, kan.li...@linux.intel.com wrote:
> @@ -900,6 +901,13 @@ enum perf_event_type {
> * char data[size]; } && PERF_SAMPLE_AUX
> * { u64 data_page_size;} &&
> PERF_SAMPLE_DATA_PAGE_SIZE
> * { u64 code_page_size;} &&
> PERF_SAMPLE_CODE_PAGE_SIZE
> + * { union {
> + * u64 weight_ext;
> + * struct {
> + * u64 instr_latency:16,
> + * reserved:48;
> + * };
> + * } && PERF_SAMPLE_WEIGHT_EXT
> * };
> */
> PERF_RECORD_SAMPLE = 9,
> @@ -1248,4 +1256,12 @@ struct perf_branch_entry {
> reserved:40;
> };
>
> +union perf_weight_ext {
> + __u64 val;
> + struct {
> + __u64 instr_latency:16,
> + reserved:48;
> + };
> +};
> +
> #endif /* _UAPI_LINUX_PERF_EVENT_H */
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 55d1879..9363d12 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -1903,6 +1903,9 @@ static void __perf_event_header_size(struct perf_event
> *event, u64 sample_type)
> if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
> size += sizeof(data->code_page_size);
>
> + if (sample_type & PERF_SAMPLE_WEIGHT_EXT)
> + size += sizeof(data->weight_ext);
> +
> event->header_size = size;
> }
>
> @@ -6952,6 +6955,9 @@ void perf_output_sample(struct perf_output_handle
> *handle,
> perf_aux_sample_output(event, handle, data);
> }
>
> + if (sample_type & PERF_SAMPLE_WEIGHT_EXT)
> + perf_output_put(handle, data->weight_ext);
> +
> if (!event->attr.watermark) {
> int wakeup_events = event->attr.wakeup_events;
>
This patch is broken and will expose uninitialized kernel stack.
