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SubjectRe: [PATCH] coresight: tmc-etr: Fix perf_data check.
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On 09/08/2019 21:23, Yabin Cui wrote:
> When tracing etm data of multiple threads on multiple cpus through
> perf interface, each cpu has a unique etr_perf_buffer while sharing
> the same etr device. There is no guarantee that the last cpu starts
> etm tracing also stops last. This makes perf_data check fail.
>
> Fix it by checking etr_buf instead of etr_perf_buffer.

Please could you add a Fixes tag for this:

Fixes: 3147da92a8a81fc3 ("coresight: tmc-etr: Allocate and free ETR memory
buffers for CPU-wide scenarios")

as the problem was introduced as a side effect of the above patch ?

>
> Signed-off-by: Yabin Cui <yabinc@google.com>
> ---
> drivers/hwtracing/coresight/coresight-tmc-etr.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> index 17006705287a..f466f05afe08 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> @@ -1484,7 +1484,7 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
> goto out;
> }
>
> - if (WARN_ON(drvdata->perf_data != etr_perf)) {
> + if (WARN_ON(drvdata->perf_data != etr_buf)) {
> lost = true;
> spin_unlock_irqrestore(&drvdata->spinlock, flags);
> goto out;
> @@ -1556,7 +1556,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
> }
>
> etr_perf->head = PERF_IDX2OFF(handle->head, etr_perf);
> - drvdata->perf_data = etr_perf;
> + drvdata->perf_data = etr_perf->etr_buf;

minor nit: Now that we are storing the etr_buf instead of the etr_perf_buf in
perf_data, we could make the "perf_data" => "perf_buf" inline with the
sysfs_buf.

Either ways:

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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