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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Q9zk297THX4H5OMLWMPzvQnkBXjtdbn8SN7VfoseWtmUpqPBxWsqKYgiP0oh?= =?us-ascii?Q?KDlfT99mCNTzbBRnWJyUHhbGRb3KiXBod1EiyEmnzyYVAvqZbHCazwGDav4Y?= =?us-ascii?Q?j3w2dUPllbC1w2LFje3A8StLsW0RILnJKQIOdLs/zPy32INVJGy7jxZ/EkJl?= =?us-ascii?Q?xoaMs7PdwHfjJhF8alIPEGTDTRKueMZEBETxNVWxf2YoVV4XWEV4C561ohVe?= =?us-ascii?Q?mi+7cGrr74f4TL26nvawmASx9276uMbepTqa0qltZfjF/+KenvfI0IEuH0aC?= =?us-ascii?Q?n44ruALnUi36iyMUWuClwGYKgiK2u9/qS1UGJtkNsu3HVpmUPyzmACZ2x7oY?= =?us-ascii?Q?o7BZpLwjDtJ5+5CY1RUaLLPE+Ug0anXlP1jGKPdRcq3DjajjDuk0o2exq6Zh?= =?us-ascii?Q?78Kk4j2RCqURIUNQuho1OXcVL++MGxd/5XnniH+in/2VUr3JHUI1WmijXkkf?= =?us-ascii?Q?BwjYIUvR9bV7UECxmU07GOMWOHdYMJvCzvrO0D3F7llQhBxpGFfWMzME9Ywb?= =?us-ascii?Q?BHxv2ilB6BJoxVypak5Sq4fQmFKyHHZGKUYF5atsmbKOnEUp7QvArAskjrlW?= =?us-ascii?Q?Bf+2xAuDAe4apQ7Vd+MsgLdxrxiQ/d8DADjY0/s4Kymmi6JQtWCZPXa+mQIW?= =?us-ascii?Q?DBNcUxWsISDF3bgqn9ctTCUBbl4h32EyqU01+HtWV244BRMSLlbPKEe0FIW4?= =?us-ascii?Q?aukY7ZWvSEhtw+rV4g90+3L6VX242xwSUoRXwTTG40WERDIjJvcKU/ZpAbPA?= =?us-ascii?Q?p5xHbkeIFiPTcoJySOuuWPthMC/ajCzEPJBcap6K9eTK01PyMez1LXpzcly8?= =?us-ascii?Q?raor5ctl+XqGSZVwtPSKqpSJuMsusCWpN1r0kBN97Br5KebQvfz3Bww/OQW0?= =?us-ascii?Q?LXidDFwJ0h2p1Xmq0gHK1BLo5vWTVAVwwI9GPqSZP4sI8AuLnNb2Uqf2UEIP?= =?us-ascii?Q?w5JXTZrkgGYJCtNoANtfT9nUInDbzil24CwamsaxFmDW4jg8PFJNkpcKfaNZ?= =?us-ascii?Q?zTxxokmJhQ5c4ikQ2Yi8O6OZ+mTRDLXcBh9rG+dhKakLytWFYwKWBRyVGXgQ?= =?us-ascii?Q?Xy684k1XiGvE4dNKxFUiaFV30oVfTgCvqr4KtRwCyS6jsbdwLrt9qImgnGlS?= =?us-ascii?Q?zLYzk5ucO5Av23XYEH/rYzR5p9XyABV6gy2TR6cVm+Q60ArBuVs5zopqSaKt?= =?us-ascii?Q?9JgcBEP70srsMHfjtMLCHoZfolnUAaBQhaWMzzC4s1KtSUgbkw3ZHimNhze2?= =?us-ascii?Q?eCW49jU6RaZzcmQtHbQquI/xLVPFssFFexdgbEt/60iirMTZIb5jOF0TaTfb?= =?us-ascii?Q?7F85+vsaZ+lE4PqMOR+b7XsOT6ETogO2zpamJbOrLTBjknzaQVBK8Rd0vSst?= =?us-ascii?Q?ZmWgye7wzq1/+sytoP5qlKVSAn9RhE86/11yYU9YnHPth785fAD2XBm+o0e1?= =?us-ascii?Q?Lzsql+H9VNQn6OYM0uFNfZGrVQ+YYaGNeROhR3qB29WKmy+PD1D/E57Xf9s8?= =?us-ascii?Q?TpnbVP3KUubghIjbieyXOThAfwSFvMq3VXz46kXZSMaOo4pnrkILVZBTbwcf?= =?us-ascii?Q?D4/NcuY7ys9mcfu6oPraAIIocIMzbOdFfjbDM9qL?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8141e814-d403-400f-e8ab-08ddd10932a4 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Aug 2025 14:39:19.3941 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: eY1YxfxsEIQBfvoSDYQ/cSDgwbrqEjd/syyRNIWZUw7fEg3Xw2hjuiPEd39Qaay8vJujLyTaNOP/ggni2aC0zw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB8480 Hi Christian, thanks for tackling this! Comments below. On Fri, Aug 01, 2025 at 03:17:38PM +0100, Christian Loehle wrote: > scx_bpf_cpu_rq() currently allows accessing struct rq fields without > holding the associated rq. > It is being used by scx_cosmos, scx_flash, scx_lavd, scx_layered, and > scx_tickless. Fortunately it is only ever used to fetch rq->curr. > So provide an alternative scx_bpf_remote_curr() that doesn't expose > struct rq and harden scx_bpf_cpu_rq() by ensuring we hold the rq lock. > > This also simplifies scx code from: > > rq = scx_bpf_cpu_rq(cpu); > if (!rq) > return; > p = rq->curr > if (!p) > return; > /* ... Do something with p */ > > into: > > p = scx_bpf_remote_curr(cpu); > if (!p) > return; > /* ... Do something with p */ To be 100% correct I think we should do something similar to bpf_task_from_pid(), acquire a reference to the task and release it via bpf_task_release(). Basically: p = scx_bpf_remote_curr(cpu); if (!p) return; /* ... Do something with p */ bpf_task_release(p); Thanks -Andrea