linux-kernel - [PATCH v3 2/2] perf stat: Stop repeating when ref_perf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240913101456.633819-3-yeoreum.yun@arm.com>
Date: Fri, 13 Sep 2024 11:14:56 +0100
From: Levi Yun <yeoreum.yun@....com>
To: peterz@...radead.org,
	mingo@...hat.com,
	acme@...nel.org,
	namhyung@...nel.org,
	mark.rutland@....com,
	alexander.shishkin@...ux.intel.com,
	jolsa@...nel.org,
	irogers@...gle.com,
	james.clark@...aro.org,
	asmadeus@...ewreck.org
Cc: linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	nd@....com,
	Levi Yun <yeoreum.yun@....com>
Subject: [PATCH v3 2/2] perf stat: Stop repeating when ref_perf_stat() returns -1

Exit when run_perf_stat() returns an error to avoid continuously
repeating the same error message. It's not expected that COUNTER_FATAL
or internal errors are recoverable so there's no point in retrying.

This fixes the following flood of error messages for permission issues,
for example when perf_event_paranoid==3:
  perf stat -r 1044 -- false

  Error:
  Access to performance monitoring and observability operations is limited.
  ...
  Error:
  Access to performance monitoring and observability operations is limited.
  ...
  (repeating for 1044 times).

Signed-off-by: Levi Yun <yeoreum.yun@....com>
---
 tools/perf/builtin-stat.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 954eb37ce7b8..d25528ea7e40 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2875,7 +2875,19 @@ int cmd_stat(int argc, const char **argv)
 			evlist__reset_prev_raw_counts(evsel_list);
 
 		status = run_perf_stat(argc, argv, run_idx);
-		if (forever && status != -1 && !interval) {
+
+		/*
+		 * Returns -1 for fatal errors which signifies to not continue
+		 * when in repeat mode.
+		 *
+		 * Returns < -1 error codes when stat record is used. These
+		 * result in the stat information being displayed, but writing
+		 * to the file fails and is non fatal.
+		 */
+		if (status == -1)
+			break;
+
+		if (forever && !interval) {
 			print_counters(NULL, argc, argv);
 			perf_stat__reset_stats();
 		}
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}