From nobody Sat Oct 11 08:30:36 2025 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38F1F21B9FF for ; Wed, 11 Jun 2025 16:02:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749657752; cv=none; b=N19orfwR3uJRiahizkVH2CMm+AdOKCTXGaICO5f+UWyJn2bZfrniPPjJz6P/PmDdOloB/YeSjhKdK8hhiwpMpILB2fFXIoQn9epDNVHlaJK37+nXv58ucJ5R4Km1WDOQyHGJ1oBqO0uSqJQREqdc4TRrxwLmLCaczETV5Yu68Q0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749657752; c=relaxed/simple; bh=lMUzWucCt2ROmASLRaeGsCDbhBIUAz/hWwGBLXVbmLk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=Ahw0BQE6Owm0T0qGgXk3iFP80gngQFkkiaVgnHaSAnnXbDE+EGac2Frwv3nGp5LF/wgBWq2zpyAem4pGqd2g5oEv7u2kut1eJdVFNKF4Ff+t2fu0JovV14rHd7qN1jl0Ue65q+2kPSvMUN5a9cIAkQXWobOvZjpuXBx04NzWBL0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=X5CG/QBv; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="X5CG/QBv" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-23536f7c2d7so104774225ad.2 for ; Wed, 11 Jun 2025 09:02:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1749657750; x=1750262550; darn=vger.kernel.org; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=nK9QQXvMHqIOnx7BDdzxOsoSdak/8YKazW30SmjV1l8=; b=X5CG/QBvdscGiCcYoikUF+y5ufKZcqVSAjPcgdk//nh3QGruHN9Gl8auT7PfSXKvJZ g57UUzj25J9l+HJGYlgTmG9YxhTfl6FE6/hIbo/5WZdYArNBlB3Gm7JIoni8DvLfaUHp AIbqeEFpzYnIc/2G0MAtxQxMB4qpdA2QG8k2nZwrkX+JeQqJubobWuYNyehGwhIcXdsc 2umuK+KbgAdpUbNoTI4nnPpgEbB9ZlA+ILHKE1VcHpnYQlnUTX9GeIl1m4L+1PeGHXn9 /ZOZFTXrkSLYyvVasHQcvnMNebay6+hRWeCj1UepSzK4phwB1jBPSeCxWF38D2iX3y6p gayQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749657750; x=1750262550; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nK9QQXvMHqIOnx7BDdzxOsoSdak/8YKazW30SmjV1l8=; b=uytVYeQIeoZPOXE5PTaeiTnWssBrTq7MwnU/vmlSiUZu1AQGuLkDvQOskvblXmRI83 KwiHNZadlw/72xKHZGcNAfQslNB436mg4rPVpIPNDzZkremawlbNMWDmQcj0Vtn0KA8r 5OlL28to00Fswn2M4dn8a2blN4AlrrdvPTmqIBwv10uzvcICbyVm1JR+R8CujOUVubql QNcGbCmyIaaG1xnxYv1cUcBOWdiA5NER2LN+b1dya+GjIf9dSaQcoT7nhRUDGkyCq7qD aqED0rfinJmvPn7AHT+5FdMfHdCg1VvBfOPiouLAMV7Jh2U4e4CFCltClNga+faDaB9y uovQ== X-Forwarded-Encrypted: i=1; AJvYcCXk0D6u7gTuauV0zIGyk/4Rsj/ffj96SEwIEF/E9M2pAgHWi1caxCAADHrxlYuTW2aZqEQSmZzK7NonnHg=@vger.kernel.org X-Gm-Message-State: AOJu0YyY1QpMl3sARrlFJYGgQ75C0lpYMlNX5hhWdU9B0eh7Tuv70RDl PjIzZKfoIdKjZH8iWHwoa5HG7I++DHHBoqV5T/FC6bS5MBjb5bRCbVmtsTQuRKO4FuqGkuCo3hO fKCM0PpCeAw== X-Google-Smtp-Source: AGHT+IFwynm1t6c+9BuOMfilAtMdqdGHfJBn6YJirPC4Yz8p5qPArARQgQARTAV9Uf7sO1arawH6VL/ym+Fq X-Received: from plhy18.prod.google.com ([2002:a17:902:d652:b0:235:54f:4f12]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:d547:b0:235:ea29:28e9 with SMTP id d9443c01a7336-23641b15570mr61294375ad.38.1749657750396; Wed, 11 Jun 2025 09:02:30 -0700 (PDT) Date: Wed, 11 Jun 2025 09:02:01 -0700 In-Reply-To: <20250611160206.552030-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250611160206.552030-1-irogers@google.com> X-Mailer: git-send-email 2.50.0.rc0.642.g800a2b2222-goog Message-ID: <20250611160206.552030-11-irogers@google.com> Subject: [PATCH v2 10/15] perf pmu: Tolerate failure to read the type for wellknown PMUs From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , James Clark , Xu Yang , John Garry , "Masami Hiramatsu (Google)" , Howard Chu , Weilin Wang , Thomas Richter , Andi Kleen , Tiezhu Yang , Gautam Menghani , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If sysfs isn't mounted then we may fail to read a PMU's type. In this situation resort to lookup of wellknown types. Only applies to software, tracepoint and breakpoint PMUs. Signed-off-by: Ian Rogers --- tools/perf/util/pmu.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 76b7ded7fbf4..c0c12880146a 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -1180,6 +1180,32 @@ int perf_pmu__init(struct perf_pmu *pmu, __u32 type,= const char *name) return 0; } =20 +static __u32 wellknown_pmu_type(const char *pmu_name) +{ + struct { + const char *pmu_name; + __u32 type; + } wellknown_pmus[] =3D { + { + "software", + PERF_TYPE_SOFTWARE + }, + { + "tracepoint", + PERF_TYPE_TRACEPOINT + }, + { + "breakpoint", + PERF_TYPE_BREAKPOINT + }, + }; + for (size_t i =3D 0; i < ARRAY_SIZE(wellknown_pmus); i++) { + if (!strcmp(wellknown_pmus[i].pmu_name, pmu_name)) + return wellknown_pmus[i].type; + } + return PERF_TYPE_MAX; +} + struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const= char *name, bool eager_load) { @@ -1199,8 +1225,12 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *= pmus, int dirfd, const char * that type value is successfully assigned (return 1). */ if (perf_pmu__scan_file_at(pmu, dirfd, "type", "%u", &pmu->type) !=3D 1) { - perf_pmu__delete(pmu); - return NULL; + /* Double check the PMU's name isn't wellknown. */ + pmu->type =3D wellknown_pmu_type(name); + if (pmu->type =3D=3D PERF_TYPE_MAX) { + perf_pmu__delete(pmu); + return NULL; + } } =20 /* --=20 2.50.0.rc0.642.g800a2b2222-goog