[4.16,222/279] perf cs-etm: Support unknown_thread in cs_etm_auxtrace

Commit Message

Greg KH June 18, 2018, 8:13 a.m. UTC

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Leo Yan <[e-mail]>

[ Upstream commit 46d53620044f7b574c0f3216f8b4f2ce3559ce31 ]

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 a segmentation fault when
thread__find_addr_map() accesses the thread handler.

This commit creates a 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 <[e-mail]>
Acked-by: Mathieu Poirier <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>
Signed-off-by: Sasha Levin <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>
---
 tools/perf/util/cs-etm.c |   24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

Patch

--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -212,6 +212,7 @@  static void cs_etm__free(struct perf_ses
 	for (i = 0; i < aux->num_cpu; i++)
 		zfree(&aux->metadata[i]);
 
+	thread__zput(aux->unknown_thread);
 	zfree(&aux->metadata);
 	zfree(&aux);
 }
@@ -980,6 +981,23 @@  int cs_etm__process_auxtrace_info(union
 	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;
@@ -994,16 +1012,18 @@  int cs_etm__process_auxtrace_info(union
 
 	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;