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Wed, 18 Mar 2026 02:50:18 -0700 From: Sumit Gupta To: , , , , , CC: , , , , , "Rafael J . Wysocki" Subject: [PATCH] ACPI: CPPC: Check cpc_read() return values consistently Date: Wed, 18 Mar 2026 15:20:05 +0530 Message-ID: <20260318095005.2437960-1-sumitg@nvidia.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-NVConfidentiality: public Content-Transfer-Encoding: quoted-printable X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN3PEPF0000B36D:EE_|CH2PR12MB9459:EE_ X-MS-Office365-Filtering-Correlation-Id: 22b6ff61-f8d9-4dfc-7eff-08de84d3cee7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|36860700016|82310400026|376014|13003099007|56012099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:216.228.117.160;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge1.nvidia.com;CAT:NONE;SFS:(13230040)(1800799024)(36860700016)(82310400026)(376014)(13003099007)(56012099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 4XTKGr21SlCESGQAF8ZyYz5oY+mtLWmsShhsGnNNUvKDVTQDKn79G/R9gJPKSL6SK5SNajqOS/qbpcJKkJy+44WjsbynNLCIJC7mhK6nVO2wOrjH2Iaxh/IRkkhTJCEzum4B7f2EP2DEb9aLLycSWtkCXw6l+EA7JW2Ue6zL6eoO1iDiG/G+BrrfPZYEnuKBcDBH9/8eJxw7pK1jpvsTNdqVwE6zRCNh6gJpe5hRtf5I/GK48WGKlRr+nQ2Bh9CgpGWa3o3CHZpqb5q9NMRyzXWMUzFKM9V+sjdilXfc3rd0lTwQ4tMSN2DssMTU5Q0DGjX+EBXEhpJFOiJOMGQZs6fX+yECxR6kb7QOylek006bJkLS1H12Yc70tshTxQIlTvGTlw6Z3ZKz6CPzyqSlPBf0b9l8UB0t9YjsAEzKq/0vZqOfMXx7oQMMDPCtX8ze X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Mar 2026 09:50:37.5559 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 22b6ff61-f8d9-4dfc-7eff-08de84d3cee7 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN3PEPF0000B36D.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB9459 Content-Type: text/plain; charset="utf-8" Callers of cpc_read() ignore its return value, which can lead to using uninitialized or stale values when the read fails. Fix this by consistently checking cpc_read() return values in cppc_get_perf_caps(), cppc_get_perf_ctrs(), and cppc_get_perf(). Depends-on: https://lore.kernel.org/lkml/20260206142658.72583-2-sumitg@nvid= ia.com/ Link: https://lore.kernel.org/lkml/48bdf87e-39f1-402f-a7dc-1a0e1e7a819d@nvi= dia.com/ Suggested-by: Rafael J. Wysocki Signed-off-by: Sumit Gupta --- drivers/acpi/cppc_acpi.c | 99 +++++++++++++++++++++++++++++----------- 1 file changed, 72 insertions(+), 27 deletions(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 5ad922eb937a..053fc6765a59 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1394,45 +1394,66 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf= _caps *perf_caps) } } =20 - cpc_read(cpunum, highest_reg, &high); + ret =3D cpc_read(cpunum, highest_reg, &high); + if (ret) + goto out_err; perf_caps->highest_perf =3D high; =20 - cpc_read(cpunum, lowest_reg, &low); + ret =3D cpc_read(cpunum, lowest_reg, &low); + if (ret) + goto out_err; perf_caps->lowest_perf =3D low; =20 - cpc_read(cpunum, nominal_reg, &nom); + ret =3D cpc_read(cpunum, nominal_reg, &nom); + if (ret) + goto out_err; perf_caps->nominal_perf =3D nom; =20 /* * If reference perf register is not supported then we should * use the nominal perf value */ - if (CPC_SUPPORTED(reference_reg)) - cpc_read(cpunum, reference_reg, &ref); - else + if (CPC_SUPPORTED(reference_reg)) { + ret =3D cpc_read(cpunum, reference_reg, &ref); + if (ret) + goto out_err; + } else { ref =3D nom; + } perf_caps->reference_perf =3D ref; =20 if (guaranteed_reg->type !=3D ACPI_TYPE_BUFFER || IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) { perf_caps->guaranteed_perf =3D 0; } else { - cpc_read(cpunum, guaranteed_reg, &guaranteed); + ret =3D cpc_read(cpunum, guaranteed_reg, &guaranteed); + if (ret) + goto out_err; perf_caps->guaranteed_perf =3D guaranteed; } =20 - cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear); + ret =3D cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear); + if (ret) + goto out_err; perf_caps->lowest_nonlinear_perf =3D min_nonlinear; =20 - if (!high || !low || !nom || !ref || !min_nonlinear) + if (!high || !low || !nom || !ref || !min_nonlinear) { ret =3D -EFAULT; + goto out_err; + } =20 /* Read optional lowest and nominal frequencies if present */ - if (CPC_SUPPORTED(low_freq_reg)) - cpc_read(cpunum, low_freq_reg, &low_f); + if (CPC_SUPPORTED(low_freq_reg)) { + ret =3D cpc_read(cpunum, low_freq_reg, &low_f); + if (ret) + goto out_err; + } =20 - if (CPC_SUPPORTED(nom_freq_reg)) - cpc_read(cpunum, nom_freq_reg, &nom_f); + if (CPC_SUPPORTED(nom_freq_reg)) { + ret =3D cpc_read(cpunum, nom_freq_reg, &nom_f); + if (ret) + goto out_err; + } =20 perf_caps->lowest_freq =3D low_f; perf_caps->nominal_freq =3D nom_f; @@ -1526,16 +1547,25 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf= _fb_ctrs *perf_fb_ctrs) } } =20 - cpc_read(cpunum, delivered_reg, &delivered); - cpc_read(cpunum, reference_reg, &reference); + ret =3D cpc_read(cpunum, delivered_reg, &delivered); + if (ret) + goto out_err; + + ret =3D cpc_read(cpunum, reference_reg, &reference); + if (ret) + goto out_err; + /* * Per spec, if ctr_wrap_time optional register is unsupported, then the * performance counters are assumed to never wrap during the lifetime of * platform */ ctr_wrap_time =3D (u64)(~((u64)0)); - if (CPC_SUPPORTED(ctr_wrap_reg)) - cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time); + if (CPC_SUPPORTED(ctr_wrap_reg)) { + ret =3D cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time); + if (ret) + goto out_err; + } =20 if (!delivered || !reference) { ret =3D -EFAULT; @@ -1811,24 +1841,39 @@ int cppc_get_perf(int cpu, struct cppc_perf_ctrls *= perf_ctrls) } =20 /* Read optional elements if present */ - if (CPC_SUPPORTED(max_perf_reg)) - cpc_read(cpu, max_perf_reg, &max); + if (CPC_SUPPORTED(max_perf_reg)) { + ret =3D cpc_read(cpu, max_perf_reg, &max); + if (ret) + goto out_err; + } perf_ctrls->max_perf =3D max; =20 - if (CPC_SUPPORTED(min_perf_reg)) - cpc_read(cpu, min_perf_reg, &min); + if (CPC_SUPPORTED(min_perf_reg)) { + ret =3D cpc_read(cpu, min_perf_reg, &min); + if (ret) + goto out_err; + } perf_ctrls->min_perf =3D min; =20 - if (CPC_SUPPORTED(desired_perf_reg)) - cpc_read(cpu, desired_perf_reg, &desired_perf); + if (CPC_SUPPORTED(desired_perf_reg)) { + ret =3D cpc_read(cpu, desired_perf_reg, &desired_perf); + if (ret) + goto out_err; + } perf_ctrls->desired_perf =3D desired_perf; =20 - if (CPC_SUPPORTED(energy_perf_reg)) - cpc_read(cpu, energy_perf_reg, &energy_perf); + if (CPC_SUPPORTED(energy_perf_reg)) { + ret =3D cpc_read(cpu, energy_perf_reg, &energy_perf); + if (ret) + goto out_err; + } perf_ctrls->energy_perf =3D energy_perf; =20 - if (CPC_SUPPORTED(auto_sel_reg)) - cpc_read(cpu, auto_sel_reg, &auto_sel); + if (CPC_SUPPORTED(auto_sel_reg)) { + ret =3D cpc_read(cpu, auto_sel_reg, &auto_sel); + if (ret) + goto out_err; + } perf_ctrls->auto_sel =3D (bool)auto_sel; =20 out_err: --=20 2.34.1