linux-kernel - [PATCH 5/8] perf cs-etm: Fix endless record after being terminated

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Date:   Thu, 20 Feb 2020 22:53:07 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
        Clark Williams <williams@...hat.com>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        Wei Li <liwei391@...wei.com>, Leo Yan <leo.yan@...aro.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Jiri Olsa <jolsa@...hat.com>,
        Tan Xiaojun <tanxiaojun@...wei.com>, stable@...r.kernel.org,
        Adrian Hunter <adrian.hunter@...el.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 5/8] perf cs-etm: Fix endless record after being terminated

From: Wei Li <liwei391@...wei.com>

In __cmd_record(), when receiving SIGINT(ctrl + c), a 'done' flag will
be set and the event list will be disabled by evlist__disable() once.

While in auxtrace_record.read_finish(), the related events will be
enabled again, if they are continuous, the recording seems to be
endless.

If the cs_etm event is disabled, we don't enable it again here.

Note: This patch is NOT tested since i don't have such a machine with
coresight feature, but the code seems buggy same as arm-spe and
intel-pt.

Tester notes:

Thanks for looping, Adrian.  Applied this patch and tested with
CoreSight on juno board, it works well.

Signed-off-by: Wei Li <liwei391@...wei.com>
Reviewed-by: Leo Yan <leo.yan@...aro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>
Tested-by: Leo Yan <leo.yan@...aro.org>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Tan Xiaojun <tanxiaojun@...wei.com>
Cc: stable@...r.kernel.org # 5.4+
Link: http://lore.kernel.org/lkml/20200214132654.20395-4-adrian.hunter@intel.com
[ahunter: removed redundant 'else' after 'return']
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/arch/arm/util/cs-etm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index 2898cfdf8fe1..60141c3007a9 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -865,9 +865,12 @@ static int cs_etm_read_finish(struct auxtrace_record *itr, int idx)
 	struct evsel *evsel;
 
 	evlist__for_each_entry(ptr->evlist, evsel) {
-		if (evsel->core.attr.type == ptr->cs_etm_pmu->type)
+		if (evsel->core.attr.type == ptr->cs_etm_pmu->type) {
+			if (evsel->disabled)
+				return 0;
 			return perf_evlist__enable_event_idx(ptr->evlist,
 							     evsel, idx);
+		}
 	}
 
 	return -EINVAL;
-- 
2.21.1