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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?fHhUfO0PL5Ply3+v91TikLj35brtFxgedLfzqekZTUPBJqp/XjxfeZK7OJQt?= =?us-ascii?Q?SEOxa3Uw7Gb5grzmV69RJ0RCtHvsYCl28Oyf5z95c3PDx4PdUGjWosKnhoXZ?= =?us-ascii?Q?SIpklKcVnDG0dtRF8zgq/fLoh9hRN5Mu/DwlhmV1qwY6rGKL1oH7a3s3b/kb?= =?us-ascii?Q?3615v6MyfdUzlx0l3e6eFZle94JbC5ggEiuyabPqGgrwmUfPv2zsDxt38dwA?= =?us-ascii?Q?nrdXS4uSnMxceyYbuQRhzIofPP+8sxANT+dnp6nfNW/lof+sknlLJz/04IKu?= =?us-ascii?Q?bRTs/wy42paJYkKLeDnFROFqnRAYvA75BT4o111wo/gOiLgtypWEEFKKK+jJ?= =?us-ascii?Q?ZlJBMvWgXJcBl1hQEemLVBQ4C45irCtBhs1R1/wGydZoEh/XGsrehIu0tmG/?= =?us-ascii?Q?i38u6HkmdBUXZTG9F7KCBl+0XKgPUIyNBp4lcfNBL2Kxlzab0Nq/jjPqhabM?= =?us-ascii?Q?Q/wmyuM+3GsTEFao2IjLsXBtB3NE96ejMOpj/FBHTIjWi7ysYbmgEE+QbnPg?= =?us-ascii?Q?nVaiFS9DTu5gc3bTJN8MrCj7JEbhvi71X4jzi2NXMl29mvTkJnyjMDtIaB1C?= =?us-ascii?Q?1zhUnjc6K6xLRQKcvJ5HTlKMc6v1Gx2IVUWvnf4AzoArNGAu6jx3wGZjRNFF?= =?us-ascii?Q?DhBt3sHYGOSobn97/HTjFnanLetYpTromscSwyum7qo/5+zgsydk9+pxTNtL?= =?us-ascii?Q?U+XRyqtvCy7MeoWPOGZ/hpUBkAvaB99eL9O8l1e1Cv3bTWLNn6vcTV1C4IpO?= =?us-ascii?Q?0K2eZrQyoyAt2jl5NydIHAPbYNU6GmHU8EpwvVV+WcGapswQG/YhbfqXPWcQ?= =?us-ascii?Q?os9+9aV0DlYJ3TTXq3SjvI24vp7wHj+iiTgSRYSl7hLfCO3cHsgs02FDDOwE?= =?us-ascii?Q?QRNTnvox5H58YFLl1ggOaBXp2HulZVcWw/PhhCmtpIYo+9Q4fROdsQWo3An0?= =?us-ascii?Q?AJr1RBiYaG1weX4+IMBOZKWw+9eRb8mUKSF/Gtz1pEaujj7rgGBg0ffJMgUH?= =?us-ascii?Q?9siAVekh3PTpQ2+Om5KLpSST7J7AbQl+lf7tXzfxYoil/0bbS/wN7xknT9aM?= =?us-ascii?Q?WQ+KUDamxCsNYmpbep+NdQAhuJtWAP79mXmcKLzu/gngGg7I31MciRFwzxDD?= =?us-ascii?Q?Z4J/U3q3UB5dyTt+CiYM3P9P4E45oifrCzXett+5HMxXTB4mQhtEy3KQueY1?= =?us-ascii?Q?yGuO5dPib44xE9qbFRy3MnJH5+8SmBS+QrRf1VENAHcaatsti3WJ1rWtOAtf?= =?us-ascii?Q?JESvoEdP/wtedk7hylDlMupHyKONGcbRc04KrsE7DmkpNrGGhOAUbw5q9MKI?= =?us-ascii?Q?MiLYFIHAco1yn5SskGyQbN0aNlSO6LFSjeBiv1w4SnvabRfQIPd6dZXHfO7J?= =?us-ascii?Q?fXEvRT+D/PTPlfvlPU3U4E4z/a3eOUbjcFcB/6eODXLMPDiqDBbH8tJLHcth?= =?us-ascii?Q?G8X9PlA31yCJ9ogwm7DPG4tDjcmAXzSJiAI4fegxcgrOmBYCHhBrYfb3e8xm?= =?us-ascii?Q?zNo7PzLK2+IkzyzuIS8UCJErNa/MKssUgIl7bPICwQajUQeZXkEVYOikROJY?= =?us-ascii?Q?EzwOf7keteoSG9GblIW0gjafTQtqj9200uh61DlyApt0rLl3A8yJGQD1/vOU?= =?us-ascii?Q?vaEH7x7vHwXVSPWlgr2np/WsgHaSlHqsS9mopCJ4naFqXVTz4h10Xa5zuaAO?= =?us-ascii?Q?gkgYU/ONCNwHwoCCImOT3o8Fx9xT4kSmoysF7NTH+0nY6IVJANE+e3WPXhnp?= =?us-ascii?Q?9HTNpyCB8g=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: b2cee734-8c62-404f-0be9-08dee2b38f38 X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB4827.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jul 2026 20:56:36.4919 (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: 4MU6fD/EvUI7SeeUKWxTaDxyCa7xyQNXjSIBKEpHjOX2EOkCRfjtXMPqxxwsjtiLXEXRJXJw/4GKgK57uItyDQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB7255 Proxy execution separates the scheduling context in rq->donor from the physical execution context in rq->curr. sched_can_stop_tick() checks the latter for CFS bandwidth constraints and only does so when nr_running is one. A retained proxy donor keeps both the donor and mutex owner queued. The check therefore misses a constrained FAIR donor and may stop the tick while its runtime still needs to be enforced. Check the selected donor instead and remove the nr_running restriction. The donor being a queued FAIR task is sufficient to require bandwidth accounting regardless of other runnable tasks. Fixes: af0c8b2bf67b ("sched: Split scheduler and execution contexts") Reported-by: Sashiko Link: https://lore.kernel.org/r/20260713164807.E5ED21F00A3A@smtp.kernel.org Signed-off-by: Andrea Righi --- kernel/sched/core.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3cc6fb1d20547..f47bcfb25033a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1409,11 +1409,8 @@ static void nohz_csd_func(void *info) #endif /* CONFIG_NO_HZ_COMMON */ #ifdef CONFIG_NO_HZ_FULL -static inline bool __need_bw_check(struct rq *rq, struct task_struct *p) +static inline bool __need_bw_check(struct task_struct *p) { - if (rq->nr_running != 1) - return false; - if (p->sched_class != &fair_sched_class) return false; @@ -1462,14 +1459,17 @@ bool sched_can_stop_tick(struct rq *rq) return false; /* - * If there is one task and it has CFS runtime bandwidth constraints - * and it's on the cpu now we don't want to stop the tick. + * If the selected scheduling context has CFS runtime bandwidth + * constraints, don't stop the tick. With proxy execution, rq->donor is + * the selected scheduling context while rq->curr is the task physically + * executing on its behalf. + * * This check prevents clearing the bit if a newly enqueued task here is - * dequeued by migrating while the constrained task continues to run. + * dequeued by migrating while the constrained donor continues to run. * E.g. going from 2->1 without going through pick_next_task(). */ - if (__need_bw_check(rq, rq->curr)) { - if (cfs_task_bw_constrained(rq->curr)) + if (__need_bw_check(rq->donor)) { + if (cfs_task_bw_constrained(rq->donor)) return false; } -- 2.55.0