From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Ingo Molnar <mingo@redhat.com>,
	James Clark <james.clark@linaro.org>,
	Jiri Olsa <jolsa@kernel.org>,
	Kan Liang <kan.liang@linux.intel.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Weilin Wang <weilin.wang@intel.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12 0941/1102] perf evsel: Add per-thread warning for EOPNOTSUPP open failues
Date: Thu, 17 Sep 2026 16:14:44 +0100
Message-ID: <20260917151604.269319423@linuxfoundation.org>
In-Reply-To: <20260917151539.408551884@linuxfoundation.org>
References: <20260917151539.408551884@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

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

From: Ian Rogers <irogers@google.com>

[ Upstream commit f0869f31562bde2ed9131665f8f76ef7a3983383 ]

The mrvl_ddr_pmu will return EOPNOTSUPP if opened in per-thread
mode. Give a warning for this similar to EINVAL.

Doing this better supports metric testing with limited permissions when
the mrvl_ddr_pmu is present, as the failure to open causes the test to
skip and not fail.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Weilin Wang <weilin.wang@intel.com>
Link: https://lore.kernel.org/r/20250412004704.2297939-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/util/evsel.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 6e8d70ec05bad..37b9196dbaa32 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -3431,6 +3431,10 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
 			return scnprintf(msg, size, "%s",
 	"No hardware sampling interrupt available.\n");
 #endif
+		if (!target__has_cpu(target))
+			return scnprintf(msg, size,
+	"Unsupported event (%s) in per-thread mode, enable system wide with '-a'.",
+					evsel__name(evsel));
 		break;
 	case EBUSY:
 		if (find_process("oprofiled"))
-- 
2.53.0