From nobody Wed Oct 8 14:39:33 2025 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 CEC9B17A305 for ; Sat, 28 Jun 2025 00:09:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751069397; cv=none; b=agFS+YTsA5AurecAGWKv5fRL8YqHe78SKakg+1eYdZ7sEHFbYhjrliigbdjFLhosTtzjp9Ae6wT374PLdSFJE25qD0wlfGj3ZlXTd0szy/lPq5YXna+HrOVkhw+D0oY0OBMoIcioETiJAHcMPD9bJvkTebMNGBHjsCUR8+vyUBM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751069397; c=relaxed/simple; bh=J4OzpKjzAQvz4+NOOvDQC2wN1+kdU2op3Xo8SV5ZLbk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=GH0cAmcWQKwJHo7ZpEZn0Gt/07amsLOzl6vfwpKLnSlqPRK7640RGK4hiBk/YyQffaigB0J0Myx7KO0Wl7y6wgoUe2FsrTDMXhXZzeDCnB3f3mnzwzrltJOfNztEs2ZCW9mkX7CD+8GgWAK3B3w8pRVNskZbfHUslVigqx6016Y= 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=gKNjDDMQ; arc=none smtp.client-ip=209.85.210.201 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="gKNjDDMQ" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-747ddba7c90so385294b3a.0 for ; Fri, 27 Jun 2025 17:09:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1751069395; x=1751674195; 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=/8RYnoHHKYJ1Y4zKmI9S+F9LPJ5D9yBDipkEOnTdUXE=; b=gKNjDDMQG8hwZMGcr08TyYY1vF4eUguP7PK+E4b2Xx0Lf+eDzfiSu5lMieNiAuKfmD XLhSlygy6RDWI7X5RxnExaoUEpBtkKkzlQNMyElUyr3fBDKRjP7H1fKr0wLFo5JWtURv MgbzWE+oUYSfEmUA8AcIU+rw5Tq/NaG+uTWgmsQp25389TjJJqSQedRvSccync9iP5WB YH9Ez8Y7r5YoqlJiGjnoM4Pl2P24Swz+1fEA91VI4ubIpaVEAUsQbDNJm3qZnXExifaY 7ukYRAXcPlqHp4YSmSDJHAEMQJxmz6O1a5suj3/9xSoBUnWnrX8CYuJlzoAprgPOcls0 41+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751069395; x=1751674195; 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=/8RYnoHHKYJ1Y4zKmI9S+F9LPJ5D9yBDipkEOnTdUXE=; b=v1otm6FL9FUIUgjz2CTNppGQm0jw53A98NNcPSyb0wIbhrbm0zFmjlcynX3bPE0An+ VJ5QRB2rP90I4SZ+EmBBCQfKzy0zH47lCrsn0ubdS+Mg0QX/0/XUFMKtirrtgZt8dgE4 iNUzTP5MSsF4HGXYTk4d2wk1VaBArjcPh2OegTKwT4jLF65cVurmSJBhMkYeIYIshkAC sU2hWGCHbQAxXS3ehZw7PaR4egbxrcjrFUwha4W/tmtj0PgnMvaAIMn2dmxlW5HrNT4i v5l6Tv6IU1DY04H6Lx3i6K/efJwCjIXtqW8Z69rBiCRiUDQJhqprwKwx0HIS2V9zaPg7 6vhw== X-Forwarded-Encrypted: i=1; AJvYcCVegexE/yVEKtzniNMqsIv/I/B+WVYR/Js1K00jJnwBdu8+vbA0h/uqpByKL61zlyxUvJkhBf6PNkKuIZ4=@vger.kernel.org X-Gm-Message-State: AOJu0YwMrWVEaNTVbdz4zE3O2fPfGuD4V+Ku41ZLVeuqyKBXxcGgN6lA Fy1nO+3B5PDdSnH9gQS9LKqYP38R+/MfvHKJsjHEfdXcYr+m3Ibnx+si9XB6K58GiqrawUebiFN d71CPRlIgRA== X-Google-Smtp-Source: AGHT+IHI9yoH6ryjs/0r4lN1uoc1sVLOFEewvIRG3rwL1A72VaGHVS4LqMyQeJlSUs10Na5kPFr5nyABWMCu X-Received: from pfay37.prod.google.com ([2002:a05:6a00:1825:b0:748:f16c:14c5]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:648d:b0:1f5:769a:a4be with SMTP id adf61e73a8af0-220a181ba61mr9052587637.36.1751069395119; Fri, 27 Jun 2025 17:09:55 -0700 (PDT) Date: Fri, 27 Jun 2025 17:09:24 -0700 In-Reply-To: <20250628000929.230406-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250628000929.230406-1-irogers@google.com> X-Mailer: git-send-email 2.50.0.727.gbf7dc18ff4-goog Message-ID: <20250628000929.230406-11-irogers@google.com> Subject: [PATCH v4 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 687288991eb4..b09b2ea2407a 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -1181,6 +1181,32 @@ 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) { @@ -1200,8 +1226,12 @@ 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 2.50.0.727.gbf7dc18ff4-goog