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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by BY1PEPF0001AE17.mail.protection.outlook.com (10.167.242.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.360.3 via Frontend Transport; Sat, 22 Aug 2026 19:22:23 +0000 Received: from [127.0.1.1] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.45; Sat, 22 Aug 2026 14:22:20 -0500 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: [PATCH v5 3/4] dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-ID: <20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com> References: <20260822-dmaengine-kref-fix-v5-0-d4a4ee47d927@amd.com> In-Reply-To: <20260822-dmaengine-kref-fix-v5-0-d4a4ee47d927@amd.com> To: Vinod Koul , Frank Li , "Logan Gunthorpe" , Andrew Morton CC: , , , Shivank Garg , Sashiko , Frank Li X-Mailer: b4 0.15-dev-47d62 X-Developer-Signature: v=1; a=ed25519-sha256; t=1787426532; l=1931; i=shivankg@amd.com; s=20260518; h=from:subject:message-id; bh=QMCEnZtwHAzn8E8PmGPgLxGc/LdJXZ5sh7KxsGFDltI=; b=KgjU5RuicuFEyYxZ6qd5M4AyXQot4ng0gZS+uSFvEHOCqBaQ+uDsPDERHc+QA7hoXtUV0ei+7 FpthQZyyG8CAo0+qOeMlpR39hLdT9d/VwK79Z0pcL9pinctO93W0ptv X-Developer-Key: i=shivankg@amd.com; a=ed25519; pk=2l2QGTeXuGkZTtfmx0nPQU8iFZfjYmX/ymMojitevx4= X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BY1PEPF0001AE17:EE_|MW3PR12MB4474:EE_ X-MS-Office365-Filtering-Correlation-Id: 52f6646e-646f-464f-3072-08df0082b1ae X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700016|376014|1800799024|82310400026|23010399003|22082099003|18002099003|56012099006|13003099007|10067099003|11063799006; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(36860700016)(376014)(1800799024)(82310400026)(23010399003)(22082099003)(18002099003)(56012099006)(13003099007)(10067099003)(11063799006);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: M1KpWGkHUVH85T0eEVtau13yvDzI53MAXM9EakhMDYhDkx/vLjex+uhIsDz+LomKXHHiaArsJnHX2qWmzH5B7NZWRp9CC/MAu6JS2WIgUcmmkOUCU8NpybY4u7xoBhi8too4ZQIc8oVdkjaxwFgSolqBVBdsovKI6q6xc3yf+wV7oHu4r4irk/0d0fvveZhfeu5i1aOvUmqiYRM1quy3YuY8qkaGMveMc4cOAPGMx+Ca1xFYZoIHliLouwe78aPfl8paDcoWU5wFeQtOjWw34eiHVoIIKvVJrp+bNpJ+j4WcAeJmKQoOZyiSoc/ESKCi/fLVPomMdFx6s3FFpCIUX27OE8YK3T5PL5sCUX/d22OdOO7f+xJH+NHt6piIzSihyNhGgYtZEr2QATqM2+s7hzmivXWPfZ1zFHPAEMNn5XmrFTWl2qNG6sRSSq+g86lj X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Aug 2026 19:22:23.5364 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 52f6646e-646f-464f-3072-08df0082b1ae X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BY1PEPF0001AE17.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW3PR12MB4474 When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg --- drivers/dma/dmaengine.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index f2760b039d93..9214b9272a55 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -500,10 +500,13 @@ static int dma_chan_get(struct dma_chan *chan) */ static void dma_chan_put(struct dma_chan *chan) { + struct module *owner; + /* This channel is not in use, bail out */ if (!chan->client_count) return; + owner = dma_chan_to_owner(chan); chan->client_count--; /* This channel is not in use anymore, free it */ @@ -523,7 +526,7 @@ static void dma_chan_put(struct dma_chan *chan) /* This channel is not in use anymore, drop the device ref */ if (!chan->client_count) dma_device_put(chan->device); - module_put(dma_chan_to_owner(chan)); + module_put(owner); } enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie) -- 2.43.0