From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from MW6PR02CU001.outbound.protection.outlook.com (mail-westus2azon11012048.outbound.protection.outlook.com [52.101.48.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29A03569F1D for ; Tue, 22 Sep 2026 16:55:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.48.48 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790096106; cv=fail; b=h1K0WK6wtogWBOSCcsewcgnw3vbvsPERsQylfefP5ZV9mxusBZSxar45GSXZY8D8sC6AfoAlDJSX8Hu97tBXwJ1CR6u5kUZ3i1OThoDzZxju3pWhWcQniif1g9/Tcd/pO8jiY83tzJ+Z2AGXsEHVeQY+AGZpb8n+VTOOBVKDoDw= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790096106; c=relaxed/simple; bh=Yp6LHnlrryCkdvo8JXnws+6aakEMxrkV7LdcvWujHOY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=JlOizVJxwMLvFNVwzCWjpjlizj6I1LqaBq9M7ytX/8aEnIooNpNflEsC/uHbH32MkAJIZ0LKQqaJDwb+34s+AKA583gXv805vEfzkPopjk/kyQTUWEJ81hypZrnUL7qaFxzHXNYu7dfrUFJYY1YVzpmlum6S3HqZDYZyTV+XLhA= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=JUTM3rZ0; arc=fail smtp.client-ip=52.101.48.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="JUTM3rZ0" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=UMyCAyp+bIevy1AViFqoajzxvaY0QiMUzIMm5PQC8AipbtvPC1xsAM2kzm/Ub61OMvae8migD3TKktwG/Myq1ZvyCr34eZ8L2oy1tawl+oEKJ/vc+UBBbXFriACmsALz61GQQjYxYqGKairkJ+fkr5qKeWFw/LmrcKQhdm4uBgxR40CETt7XxnIHZNt9BSeaJl7M05qUxhBGo0/7i5zP/U2zr++0rWDHdLRXcajGlc0Rd7u87j7zHgw8uUK6WUC1KZXX/pRqVTdyn/8mrvnrDrYkAcv7Pb3Y/u29g6avNuhh8CRw44pO1arBg7BxWCcnCdAr3DRbMtcQH4M/WiOoFQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=9dOKrBfqq7SO9SYJoMNAM10KZg28qV7ZOTG+MsZtmKk=; b=HLOUkUGv0I1AdEyDKwJwHxowcF9c5qkn1ViZnncGZdcSSNREeoEuaY53qNoUntLC8rKn+iBTmbIG8q3IwjydFyfl/lWvBNwI/ZVq3hph0zA+MJZs7AZwyamMRvO0WmfQYLJxQq0QpsbJqseJ4aviBi4GXTfq5pX2mlwKGk+ENPBdm80pCMFA70gEI5MVPyn2kGPxGiI7SBNHD/k7fzr7l9bzantLKSAD89FjN4YwXo53e39o+fUXoHRA7smazcCJIiSnC2Ryf7t9S/eRn9+gJQMwjIMB7ltJ4Zd3G9rx5b7zw+UmkeHneve8C5Ct1Tw22trSP8x/Kt1dI/soLdFEAA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=9dOKrBfqq7SO9SYJoMNAM10KZg28qV7ZOTG+MsZtmKk=; b=JUTM3rZ0IFyzKFv1iq1qqR3JVpOzza3QbnQ/uMU4R8nLpfz1YRJwyrc6bAyDba/2BaAMq3c6cWgS7xumvNM3mD8PKlU9RvlgEcpdyL+VYcvYcN3ASnlpG0VeSkENLlbIGEEshUjC0zxm/2aQMdNypGkHg8+eUBJ3fYn1mk4VJQxurhDDxh218xv80K7evnEW/VvJuRwdPqv375FhT3x04g3EQWJ/kE3JEhgv3E0ap5F//PrDIuQGOLZgzY7NCR7Nfywzb1LjY4DD55m14ekVA08AtaWxQMHuihtveGVDrZTKYH9c8/8ftJMsb+lsj+BzVHWWdzlrNgdFhFust6GBhA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM6PR12MB4827.namprd12.prod.outlook.com (2603:10b6:5:1d6::14) by BY5PR12MB4100.namprd12.prod.outlook.com (2603:10b6:a03:200::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.451.14; Tue, 22 Sep 2026 16:54:57 +0000 Received: from DM6PR12MB4827.namprd12.prod.outlook.com ([fe80::6261:3040:864b:159c]) by DM6PR12MB4827.namprd12.prod.outlook.com ([fe80::6261:3040:864b:159c%7]) with mapi id 15.21.0428.015; Tue, 22 Sep 2026 16:54:56 +0000 From: Andrea Righi To: Tejun Heo , David Vernet , Changwoo Min , John Stultz Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Christian Loehle , David Dai , Koba Ko , Aiqun Yu , Shuah Khan , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 01/16] sched/core: Drop mutex locks before proxy rescheduling Date: Tue, 22 Sep 2026 18:51:40 +0200 Message-ID: <20260922165445.943315-2-arighi@nvidia.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260922165445.943315-1-arighi@nvidia.com> References: <20260922165445.943315-1-arighi@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: PR1P264CA0040.FRAP264.PROD.OUTLOOK.COM (2603:10a6:102:2cb::19) To DM6PR12MB4827.namprd12.prod.outlook.com (2603:10b6:5:1d6::14) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM6PR12MB4827:EE_|BY5PR12MB4100:EE_ X-MS-Office365-Filtering-Correlation-Id: 29ee08bf-7d7c-47ef-533f-08df18ca3ade X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016|23010399003|7416014|10067099003|11063799006|5023799004|6133799003|56012099006|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM6PR12MB4827.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(376014)(366016)(23010399003)(7416014)(10067099003)(11063799006)(5023799004)(6133799003)(56012099006)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?aBdZZh3rP/rHYWJOElAPuvZHUOKPW7zMywpwbfZOS9Cl4LBWjm/BRoGHrKJE?= =?us-ascii?Q?tRSrDG8uFkYPJhk6CWo1ISeHIN0x77vNkFLA6xgwA0vTOq86Q5qVrVF9BPRq?= =?us-ascii?Q?QVirDozVyyPokEUSiN5U/aX8Smp3we01sef1XsFviTmDUi3d2N07VOOKXQ9n?= =?us-ascii?Q?pBGF7fM2yRRRbCMP9ROryudbvSukNzlRieJR7gDoaeMz6ryRo+CtRngm40LQ?= =?us-ascii?Q?GS0ssJy/y0XTmF39K2A0dH4tQqW3dgzhkzaL8PTLC4THvGp+tQlX55bUgImH?= =?us-ascii?Q?I0J8T8pCUX9mtoyz2jxz41IJiOymyzIGsupG84ubrIGF8tFmPxTZ7FM87Rwy?= =?us-ascii?Q?9GKWALqfjfNQ9mJfJv5PnAmTXN++ruGQIiPphYvjGbxWBAypsz6QsmLh2/Rj?= =?us-ascii?Q?laGctZTGTSyvRecAt/X/NFGMJDsIsUJ7BBS1tifVZdGjGW8/GzUPArzJcdhN?= =?us-ascii?Q?e2odfTaS5L6no9GXtJ73ePEUyDhEDGv35fHRtuGjzDiJb9cbNPz7sCHitttM?= =?us-ascii?Q?RuQoF8yioqIT5tdMalM/46md+gTSthQFEU69tHlbCS0l50CfCzHShsRml4Nl?= =?us-ascii?Q?LRFS5p/UtPsqnLgrOktDOwQ+5nRhOm9aa4DURvnA3IQ8B1pmy1oUu5b/ogZ4?= =?us-ascii?Q?w/Ha2EKoO8xT8plcSeZLOaUdRhGZ+GY4lqtp9D9p7SAEO2Tb6AOWZdWFj208?= =?us-ascii?Q?pqk54yxO0gV62aWwdGG4pLptU8bbSVkdpgKPLsTR1ra+ciiUKzPlJJvgLpwX?= =?us-ascii?Q?joqW4FbImTptY+lt5Qdfz9MuYFlty6vzJ+ZkvUEKS3iL0sY9QPggcRKgmtf+?= =?us-ascii?Q?+eBc/BTpu/eIaRScBTe8qyHSx2If3l9n4SHOFLq42yo91w8VhA0R4UEW7Zg3?= =?us-ascii?Q?F//f1bRPa+zs/6uXT2h8WJMI0W5CX502KfgjsbQ9kLdbpbX3eic3278n99cK?= =?us-ascii?Q?6QBSGlKPTJ6SkvdtUXghqQci0CktoScgBVhZ+nd6RGggSRu02iSKA30naKEv?= =?us-ascii?Q?B68OyeRXdYSbjJr/4ztrzpYW4DAiNgOPlbjQB72mxOP3Rtmleu65wzgaMPdK?= =?us-ascii?Q?Jqg8DHw3rzdVebn3DRhfEvP9TnBNDmIpr1rB/zl0TeGm0aYtOJvL8Q8t1aoG?= =?us-ascii?Q?Sct+PrCF+NdVlkswJYu5ZFV79HVN4SFwa5j2F4XL+9iuCdxxarDkNny4Y46q?= =?us-ascii?Q?BNz3g2+Jj4FxYO6AMXaidxmEkKIIYI2hiTlynNbazXCQdq45Ws2oPA4GTC2W?= =?us-ascii?Q?6l1xNba4paQI3ExmhkV7HEGLwjWrmTjsZfBcomnb/kpH5hentUscm6T+4bGS?= =?us-ascii?Q?xmvJAOWts1hYujWoXowvlUUHWmuLflYrs8Dch3OsMpWJR5RT5b3hYDsHCeOd?= =?us-ascii?Q?Rbgay1tJRZXyDxDjFwa00gmVTR2A6l/jEXi0R0Z+TxNYHyjURuid8MPj27hY?= =?us-ascii?Q?sJoBEe8xIJFFJnG7rbszp50jFW506YQIrjuHLD95cjA+jTFMNxt3OOM9I2z5?= =?us-ascii?Q?YOC4ponnpeG0aMs8NE0mqZ8sSq7wNedmeOthCW7zR1gZ1P4ZSju/4Q8jQDmU?= =?us-ascii?Q?GKybI6PB9eQWaeTC9rN9DPJ4DpjxsxxLzK8sSp9E2axWfGIwXW7B5QQvLOmP?= =?us-ascii?Q?CRwfJUt1kgy64rJ10Qy/exkqTNr+hMCYw21dEw6hipc5KJRtU8HXkqLveNVr?= =?us-ascii?Q?h/an3S7l3YJSZsEJk/X0JkppB2ZS+7b9fhfavt88yGCejZDf?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 29ee08bf-7d7c-47ef-533f-08df18ca3ade X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB4827.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Sep 2026 16:54:56.3720 (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: S+BPjNPoAArf/q7BAVB8Oi5WQGbHQ73mqEqJFzGv0O9ZWdkRteob6t6T3ai0FfsfzeK4i8WdT6Ld4qmK44B4xQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR12MB4100 find_proxy_task() can call proxy_resched_idle() from return expressions inside mutex wait_lock and blocked task lock guard scopes. Return expressions are evaluated before scoped guards are released, so proxy_resched_idle() invokes scheduling-class callbacks while both raw spinlocks are held. Route these cases through a common label outside the guard scopes. The common label is required because a direct return would evaluate proxy_resched_idle() before guard cleanup and run the class callbacks under the proxy-exec locks again. This is a preparatory change to support proxy execution with sched_ext. Reviewed-by: K Prateek Nayak Signed-off-by: Andrea Righi --- kernel/sched/core.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 145eea2d99a1c..3026d01fd7aef 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6961,7 +6961,7 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) if (!READ_ONCE(owner->on_rq) || owner->se.sched_delayed) { /* XXX Don't handle blocked owners/delayed dequeue yet */ if (curr_in_chain) - return proxy_resched_idle(rq); + goto resched_idle; __clear_task_blocked_on(p, NULL); goto deactivate; } @@ -6973,7 +6973,7 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) * and leave that CPU to sort things out. */ if (curr_in_chain) - return proxy_resched_idle(rq); + goto resched_idle; goto migrate_task; } @@ -6986,7 +6986,7 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) * case we should end up back in find_proxy_task(), this time * hopefully with all relevant tasks already enqueued. */ - return proxy_resched_idle(rq); + goto resched_idle; } /* @@ -7023,7 +7023,7 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) * So schedule rq->idle so that ttwu_runnable() can get the rq * lock and mark owner as running. */ - return proxy_resched_idle(rq); + goto resched_idle; } /* * OK, now we're absolutely sure @owner is on this @@ -7035,6 +7035,8 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) WARN_ON_ONCE(owner && !owner->on_rq); return owner; +resched_idle: + return proxy_resched_idle(rq); deactivate: proxy_deactivate(rq, p); return NULL; -- 2.55.0