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Tue, 11 Nov 2025 10:58:32 -0800 Date: Tue, 11 Nov 2025 10:58:30 -0800 From: Nicolin Chen To: "Gustavo A. R. Silva" CC: "Gustavo A. R. Silva" , Jason Gunthorpe , Kevin Tian , Joerg Roedel , Will Deacon , Robin Murphy , , , Subject: Re: [PATCH][next] iommufd/iommufd_private.h: Avoid -Wflex-array-member-not-at-end warning Message-ID: References: <36cc3b51-601d-4412-9dca-9752e2d77a51@embeddedor.com> <3d50e0a2-77fd-4c87-bf74-8ab8b6b15ce2@embeddedor.com> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <3d50e0a2-77fd-4c87-bf74-8ab8b6b15ce2@embeddedor.com> X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ1PEPF0000231B:EE_|DS4PR12MB9658:EE_ X-MS-Office365-Filtering-Correlation-Id: 148a8440-bbd8-494f-938b-08de215456e8 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|1800799024|376014|7416014|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?XUX0OK32QFERryW0P0Z7yPmW3mtsuJlweU/7qsgrRhfu+XwmEZxnWn5lpdOb?= =?us-ascii?Q?8ZREmP+r1RPC6rPY17oKJLpiqXnRonWTwxLNvsb74Ma9MniuNzjJQ0R7Mwkl?= =?us-ascii?Q?egHVRq+1EixTEKFmQIaPQ78RrjpIccNlP9IJKPM5oW1GFJ8s4X6oe5/rBer0?= =?us-ascii?Q?kBFq40aZrMF3v8/aQvu7oIc1xc05GGlthAEZPdNGmRTlR3zqCngrpWfXF0P6?= =?us-ascii?Q?sRGYTEJyrsrZMPkFG9LjCXwgIVeeciYOYBydUDozsPF8BaiiEctxK3vI/Rb/?= =?us-ascii?Q?nku9IgHbAsYVwL21IZMb3dxCGK3Rsqm9qH/Vn+hcv7aJCEiI5656ui1/LFD0?= =?us-ascii?Q?9HngqmcWFij8ToaraE00JkJOI/wN6UT9Jkaoy+XM2cigR8xWqbjLdfAwmefE?= =?us-ascii?Q?JKYUDEiBEzLTtKQN4N8GBdwFFgq3DJh5WaPqeDwwF2sSV0pABZEXxjZbaFAY?= =?us-ascii?Q?e/PwRxmocltKdR9Wp6FGLufwEranxkbTATbmQLDw7k42g55a6j+ho4rDDBG8?= =?us-ascii?Q?a06dtyuNXzcXRKgxu5XrN3s3VXfyo6oXfg10XOzmUYYpFPxJB2A55mfFZzMM?= =?us-ascii?Q?fDQzpYgraH8uYDnG2PXz0Ph7FaouB+jcW+4z5162ganO/SuU9RjpKG25a7D3?= =?us-ascii?Q?4eNNpv5X2IarjW9Qp5CvG3htpBor9tQ7e5TOddj8wC+jy6akwOcu83rg3gpy?= =?us-ascii?Q?y6SDLcO8ohea6poP0EvfxRd3Vc1Jc2B4hmOPb8iEi/NXnQ8+HLAsrAFB2nDW?= =?us-ascii?Q?SqXzmu4on1UiqdKI3Wt2W8xv4W0dbZcowSNGY2CK5j0ZiRN1izFGTaBJ+PO/?= =?us-ascii?Q?8Na+KzbWwPykXSWHjFPGJbhONry44aWq9H8SyHVYeJdfwR1Qqg+0cETGh278?= =?us-ascii?Q?jT3GiI/nSotFnPORkpFdJ93ZuQJS2foicQ7STKTys+M6YNJqKIAeXZw8xBLb?= =?us-ascii?Q?Qjycg2VPTQxYZYOlmLSZSyG6OdG4PTu3jTAjR6ev0kHAlSn6Dq+LCoTU+33B?= =?us-ascii?Q?otc5+RaAOs29zYM1InMtuF0w/aicuVj8wtlM6pU3OSXEMgdX3ChkeYooJ4H5?= =?us-ascii?Q?N1/T+Xbltml/4HQYWNuh64X2hls2nx+7IlGK7f1NxdcmutKKt9VsEzkkzCb1?= =?us-ascii?Q?asMx2xeuYZhEMgnHSNGZS3wrWD0+tw2YlncUZPOVgD6uYU8UFJ+jcL+iFcKs?= =?us-ascii?Q?q+ZN171HamYTZo6rwwDKv3FNQt0XA9WCsviMWXsNzHT56KLknmF/23WW9uFz?= =?us-ascii?Q?4To3vk/OrniHEABdJgS1fZGnur1qIaiC6IWmlHo5xPlxqSeoexC8OVedRwqG?= =?us-ascii?Q?Kv7YWmpWX/nxygTAimOaDaPlNN2pzmBB7KvI/eeo/gYSgT3XDXI1Ap6PJmHt?= =?us-ascii?Q?lyobwMr92pQOa65W+0AtpAWQ2v1AEVMFhBo5mHWVRuC8if93dDUUT2GMJJkS?= =?us-ascii?Q?ZEr2bq7ePI0zTtDQvOvH6NAa20t+40+f7Lqo5Z6PFxNuzkwAkTPbUwP3bfXr?= =?us-ascii?Q?Fg0/5iyhLQdTaSpLJJOWFNU+XlUMB3mGh2ujVnGMdHNg0huH81nRRNm/odbi?= =?us-ascii?Q?hK4fN4gt/GHnp7ci/0I=3D?= 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)(36860700013)(1800799024)(376014)(7416014)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Nov 2025 18:58:45.1977 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 148a8440-bbd8-494f-938b-08de215456e8 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: SJ1PEPF0000231B.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS4PR12MB9658 On Tue, Nov 11, 2025 at 05:49:20PM +0900, Gustavo A. R. Silva wrote: > On 11/11/25 16:20, Gustavo A. R. Silva wrote: > > On 11/11/25 03:02, Nicolin Chen wrote: > > > On Mon, Nov 10, 2025 at 08:35:31PM +0900, Gustavo A. R. Silva wrote: > > > > -Wflex-array-member-not-at-end was introduced in GCC-14, and we are > > > > getting ready to enable it, globally. > > > > > > > > Move the conflicting declaration to the end of the corresponding > > > > structure. Notice that struct iommufd_vevent is a flexible > > > > structure, this is a structure that contains a flexible-array > > > > member. > > > > > > > > Fix the following warning: > > > > > > > > drivers/iommu/iommufd/iommufd_private.h:621:31: warning: > > > > structure containing a flexible array member is not at the end > > > > of another structure [-Wflex-array- member-not-at-end] > > > > > > IIUIC, there might be data corruption due to this? If so, I think > > Okay, I didn't find evidence of data corruption. So, this patch can be applied to > a -next tree. Revisiting the design, the "lost_events_header" doesn't allocate data but only uses its internal header to raise a flag. So there should not be any data corruption. Yea, I think we are fine with your for-next patch. Thanks Nicolin