[PATCH RESEND v2 1/2] perf cs-etm: Support unknown_thread in cs_etm_auxtrace

[PATCH RESEND v2 1/2] perf cs-etm: Support unknown_thread in cs_etm_auxtrace

[Leo Yan]

CoreSight doesn't allocate thread structure for unknown_thread in etm
auxtrace, so unknown_thread is NULL pointer.  If the perf data doesn't
contain valid tid and then cs_etm__mem_access() uses unknown_thread
instead as thread handler, this results in segmentation fault when
thread__find_addr_map() accesses thread handler.

This commit creates new thread data which is used by unknown_thread, so
CoreSight tracing can roll back to use unknown_thread if perf data
doesn't include valid thread info.  This commit also releases thread
data for initialization failure case and for normal auxtrace free flow.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 tools/perf/util/cs-etm.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 6533b1a..69f21de 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -239,6 +239,7 @@ static void cs_etm__free(struct perf_session *session)
 	for (i = 0; i < aux->num_cpu; i++)
 		zfree(&aux->metadata[i]);
 
+	thread__zput(aux->unknown_thread);
 	zfree(&aux->metadata);
 	zfree(&aux);
 }
@@ -1355,6 +1356,23 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
 	etm->auxtrace.free = cs_etm__free;
 	session->auxtrace = &etm->auxtrace;
 
+	etm->unknown_thread = thread__new(999999999, 999999999);
+	if (!etm->unknown_thread)
+		goto err_free_queues;
+
+	/*
+	 * Initialize list node so that at thread__zput() we can avoid
+	 * segmentation fault at list_del_init().
+	 */
+	INIT_LIST_HEAD(&etm->unknown_thread->node);
+
+	err = thread__set_comm(etm->unknown_thread, "unknown", 0);
+	if (err)
+		goto err_delete_thread;
+
+	if (thread__init_map_groups(etm->unknown_thread, etm->machine))
+		goto err_delete_thread;
+
 	if (dump_trace) {
 		cs_etm__print_auxtrace_info(auxtrace_info->priv, num_cpu);
 		return 0;
@@ -1369,16 +1387,18 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
 
 	err = cs_etm__synth_events(etm, session);
 	if (err)
-		goto err_free_queues;
+		goto err_delete_thread;
 
 	err = auxtrace_queues__process_index(&etm->queues, session);
 	if (err)
-		goto err_free_queues;
+		goto err_delete_thread;
 
 	etm->data_queued = etm->queues.populated;
 
 	return 0;
 
+err_delete_thread:
+	thread__zput(etm->unknown_thread);
 err_free_queues:
 	auxtrace_queues__free(&etm->queues);
 	session->auxtrace = NULL;
-- 
2.7.4

[PATCH RESEND v2 2/2] perf cs-etm: Remove redundant space

[Leo Yan]

There have two spaces ahead function name cs_etm__set_pid_tid_cpu(), so
remove one space and correct indentation.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 tools/perf/util/cs-etm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 69f21de..822ba91 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -611,8 +611,8 @@ cs_etm__get_trace(struct cs_etm_buffer *buff, struct cs_etm_queue *etmq)
 	return buff->len;
 }
 
-static void  cs_etm__set_pid_tid_cpu(struct cs_etm_auxtrace *etm,
-				     struct auxtrace_queue *queue)
+static void cs_etm__set_pid_tid_cpu(struct cs_etm_auxtrace *etm,
+				    struct auxtrace_queue *queue)
 {
 	struct cs_etm_queue *etmq = queue->priv;
 
-- 
2.7.4

[PATCH RESEND v2 1/2] perf cs-etm: Support unknown_thread in cs_etm_auxtrace

[Arnaldo Carvalho de Melo]

Em Thu, May 10, 2018 at 12:01:59PM +0800, Leo Yan escreveu:
> CoreSight doesn't allocate thread structure for unknown_thread in etm
> auxtrace, so unknown_thread is NULL pointer.  If the perf data doesn't
> contain valid tid and then cs_etm__mem_access() uses unknown_thread
> instead as thread handler, this results in segmentation fault when
> thread__find_addr_map() accesses thread handler.
> 
> This commit creates new thread data which is used by unknown_thread, so
> CoreSight tracing can roll back to use unknown_thread if perf data
> doesn't include valid thread info.  This commit also releases thread
> data for initialization failure case and for normal auxtrace free flow.
> 
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Thanks, applied to perf/urgent.

And please use a more descriptive, eye catching summary, something like:

  perf cs-etm: Fix segfault when accessing NULL unknown_thread variable

:-)

- Arnaldo

[PATCH RESEND v2 1/2] perf cs-etm: Support unknown_thread in cs_etm_auxtrace

[Leo Yan]

On Fri, May 11, 2018 at 10:48:00AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, May 10, 2018 at 12:01:59PM +0800, Leo Yan escreveu:
> > CoreSight doesn't allocate thread structure for unknown_thread in etm
> > auxtrace, so unknown_thread is NULL pointer.  If the perf data doesn't
> > contain valid tid and then cs_etm__mem_access() uses unknown_thread
> > instead as thread handler, this results in segmentation fault when
> > thread__find_addr_map() accesses thread handler.
> > 
> > This commit creates new thread data which is used by unknown_thread, so
> > CoreSight tracing can roll back to use unknown_thread if perf data
> > doesn't include valid thread info.  This commit also releases thread
> > data for initialization failure case and for normal auxtrace free flow.
> > 
> > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> > Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> 
> Thanks, applied to perf/urgent.
> 
> And please use a more descriptive, eye catching summary, something like:
> 
>   perf cs-etm: Fix segfault when accessing NULL unknown_thread variable
> 
> :-)

Thanks for suggestion.  Indeed, this patch is a fix rather than
a new feature, subject should reflect it.

Thanks,
Leo Yan