From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BL2PR02CU003.outbound.protection.outlook.com (mail-eastusazon11011057.outbound.protection.outlook.com [52.101.52.57]) (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 849AF32E724 for ; Mon, 26 Jan 2026 10:01:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.52.57 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769421673; cv=fail; b=j8IfKtvahFAJXdv79HqSW+AaPTcOlYuyGzciGeQas0aqyJ8EwxDP7HArdR4SAJYd58RZrumsakWj2GjGPPV3O+zvheeGqAQ4DChQjuUZqAS/8OUUlOJYxa85ewtSKEAbC8JnP/0Y2qFXSjXI6iAfQ4L4YY3P9GJ06cGW+1cyJLU= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769421673; c=relaxed/simple; bh=6vEr4bzHlEuAwz+cLeabtpEu6Lzl3CdGEZYrw23GhgQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=PbuNTCFO35gSLvjdZMwAeZsA5mBw8kV8UcqaobBOtmvXRq7AH7LBKZwjXOIsgBNsaBQXrn5FWxS/dXt9FelY6SQBs9aBk9QFoUsCRK1dlvTqkd1QkE/E5N7XAVPNrKCkvUclaMXI01q6aYZI42zKwG/FNGuesuK7w234iE97vl4= 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=GSvVCKjX; arc=fail smtp.client-ip=52.101.52.57 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="GSvVCKjX" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=qGfO0OB5QbJDxeY3VVtUYHLfju18ZX9Nok5RFI9EaH+EGTILKaRfBHwiqm+g+5xpJAO4I7oxFgkdGuuiU/Px3uBwvJbGdBxJ2S96OP9jNnv6KAPyjQLLvrpR+T5/4pkrBZR9wl08tZ6CL+PGYdO006gWqz9hn/RJHvYHn4Qh26EaeFbCGOB813c4OMJ/nyabOWtrrxd/OIZ6fuOprG74O3VgqUZ7P5P2i/xP2hBoG99uuWp5GkVwbEPhw4dIkFCjYqYrn9j74pIx4j39GzptVvqWk7SvkSkeOmKPA0JIn/1rdSlegtJDV7EIG8cHUa8mKkK2FTV2mjZPFxnbr7hk0g== 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=bLvZQJrN9sti6NuWnv7l4mZawbEJKPCb+dPs/H22E9c=; b=qrK4SlADwvXaLqERYlM7RD+TJ4kjp4iJk/JwouBrskFkcd3c9KgQj4UQ2AOlvSVhaxmnpp8dGN6y2Fz7zZOptZ81Z9X8QPG1c7lqCailVwQYmWmyGmmygKtjNpxHigy76YNoYKiBkJYaD4R6tx9j/z9zWNBIDRVmLD28yMX3XKQAX6iSSbzeGF85k5wK+FFvcmd5wh4sbVnHDwOosMAHwlPXD+7D3Bznlc9ewrf80mpIImki7hyGGCd5zDIH99Em9yDCBLz7+cwWblZxftBX2w+ZEMIcRuw9CwghAihRYGhYDQaBbsf9ouWfEpjNmJVYqP30Z2nkMPe5Rebd2HEwag== 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=bLvZQJrN9sti6NuWnv7l4mZawbEJKPCb+dPs/H22E9c=; b=GSvVCKjXF9c54xtdU6gNGckO7larpcgBhj33RrgghS7l82pO7WMDI3ejNUbohRTt2+mekOxCZGRCjUlA96pWgIsbXie72E1Mj26zbK3G7cLcQfAPbQC2MjA+fXCTzScsBtG4wIaEVOCZW7BkHPfFZKP5BxQUQjwEq7FI8nsjJI7vscvxb+lUT0kKSJEP9Yl/+H+OFPUK66oMZ0DT4Z23tOffa/RtrYQszrwPhz+VR2V02qGWAi8Xhtm3+ET1vIjeQaWybpfRzyXfNt/C057PT26jllgGbbqJDlGHOi0TAQddpzGwwx48NykXFnwTSC3hQwofH1h572vhajmwBW1+Fw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS2PR12MB9615.namprd12.prod.outlook.com (2603:10b6:8:275::18) by SJ2PR12MB8953.namprd12.prod.outlook.com (2603:10b6:a03:544::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9542.15; Mon, 26 Jan 2026 10:01:05 +0000 Received: from DS2PR12MB9615.namprd12.prod.outlook.com ([fe80::f4e9:9ad6:cb62:2c15]) by DS2PR12MB9615.namprd12.prod.outlook.com ([fe80::f4e9:9ad6:cb62:2c15%6]) with mapi id 15.20.9542.010; Mon, 26 Jan 2026 10:01:05 +0000 From: Andrea Righi To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Tejun Heo , Joel Fernandes , David Vernet , Changwoo Min , Daniel Hodges , Christian Loehle , Emil Tsalapatis , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 2/7] sched/debug: Fix updating of ppos on server write ops Date: Mon, 26 Jan 2026 10:59:00 +0100 Message-ID: <20260126100050.3854740-3-arighi@nvidia.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260126100050.3854740-1-arighi@nvidia.com> References: <20260126100050.3854740-1-arighi@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: ZR0P278CA0155.CHEP278.PROD.OUTLOOK.COM (2603:10a6:910:41::16) To DS2PR12MB9615.namprd12.prod.outlook.com (2603:10b6:8:275::18) Precedence: bulk X-Mailing-List: sched-ext@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS2PR12MB9615:EE_|SJ2PR12MB8953:EE_ X-MS-Office365-Filtering-Correlation-Id: 5f46c334-9ed4-472f-fb58-08de5cc1d1f3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|366016|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?aE244ILRIaDMNXNPwVFs4/VrLJscI/iYraRm5VL4HGgkbLpKLvnNce3W2GDM?= =?us-ascii?Q?o+N03a0cM+KLVo5Tv/xLWe6VhtfXcutOj/HLGdW1Lv2KUotLllCEjUJHFOOM?= =?us-ascii?Q?6KdSBYQBWgBh1tRSvgLSA2+sevSnrOf4C3OOnjv/kxdnb6FFGs0mxP7aq1/K?= =?us-ascii?Q?t96wMzrxWUBllXGNT5jBafodBnKY8xKExsVIX7Ljuhn7qVPxyTH/+vSVWjEC?= =?us-ascii?Q?6oxTENeU4HKh7cREdG8AqF7qw6OPF2G28xh6uFjXdJ4qqpcQXJRQBVU0W0aQ?= =?us-ascii?Q?FPislTV6GvNAML6T1yWj3YVM96ZGt5TYR2cOJkZTe7baooVNUt5wxph6f+5J?= =?us-ascii?Q?qNcvqhiJgljxAOepQqKvTlus7/29240MqX0g/KU5yjhCSZgj1WoaBJCcFTz1?= =?us-ascii?Q?kVQoLW+PFrN5CWDjaqXzu5qOA06hrAcpSzMbgO0iFXll/yopfeNZXoVJTtWF?= =?us-ascii?Q?cIY74gtgT9PAwllY++PXFmO50/x6Qk3fTFVhEAR125NQTNoioX7OEhfLy/jd?= =?us-ascii?Q?PyZjRhyoKw0zcPB+AM/0bHFnRBQHDdebGwMVIS0fivIcaa4LrQmgtVXpKsN8?= =?us-ascii?Q?hLtrfqE0Cw1HhOnIincSDm/ksHadjrv2394DB/J0CYx1ZEGUUkI2SIKDUEMQ?= =?us-ascii?Q?Nts4w01G3qKd7J1QfIKk2LatWFGPjJljlfB8wDGMWi0Alf5ymb5e7uLEatX+?= =?us-ascii?Q?6dkAmwEUT6W2q4LCymmX2qwHuONPLkAYdo2JLAz10+AOTOx3npyKshOxbs1m?= =?us-ascii?Q?zorNWDIMPLRM9EfLT3hVCfrKEZjBTNcPYAKO8HV6Ar0YWdAe2pfj5fzv4gRS?= =?us-ascii?Q?Zu7CtQmDPM6PpehhiC145Z+EwafIlbgmL9ShURSQUEMyDgS0B+nB1w9pKvCv?= =?us-ascii?Q?2Gd+wO1LPm5YTZrczMUEKgeEv/gr+OUqPTnUA7BUR2FE1u+AA6blZ0ysv7uK?= =?us-ascii?Q?P5qy+ahxOe5santd/dvMDSlO3wC6Ln2yQBIDRbmK57zmf46rXdw8V3mns4nN?= =?us-ascii?Q?sMEUtdaVo5Sc0cnrk8igey3Jh4ZGGtlvOXdyq9MGlz18gKIJ8WyoQOK9Qu/n?= =?us-ascii?Q?MaE+Ocd0nVLii7lmkAXrqQjpPCsmBFMwzzoEzKikkJbDe60WpXjbIAk7/6sq?= =?us-ascii?Q?DVEGekOTPgKIb+HDLC+qBLbr6VuO8YEl73nvTYXVu4wEUMgw8hOh4OGWmbV4?= =?us-ascii?Q?fgWdUln4dwoFQYY+H2bHUbmMRZVCWnJ62Uo17PkZrvixEUzwIzF+ePWkkn2K?= =?us-ascii?Q?WoVPy+KIfVlEiIfm0ppL/BqL4ClpRw5Wqhjer/EmEWEyLPlheFYM96izAc0b?= =?us-ascii?Q?Buf2L/H86ZAfAxVR59QGrYVRl4Ech7KM21j4FAo0qxf3t6NJMMCKeQG1rO+M?= =?us-ascii?Q?bXCjKjGzuV8qu47nGWVH1zzUDMrPrtEVMpjR6v+eqq7LgvOHHPxfec6NUsg4?= =?us-ascii?Q?hKQWRa5CKUxLzv3EJMY2wP9ZHzew1bbtmliygUaFUzoHEuyypCzjYozbDQ6X?= =?us-ascii?Q?Zx+7ATWlMlwyh+RDzDSJp+GYb9EUKq5ng9AirHi+qysTRqdDGfpqwaNH41PA?= =?us-ascii?Q?yH9ti5rwMIrxusnX18k=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS2PR12MB9615.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(366016)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?hDF8EklBhdoPp2DFhlN/V8vc9ejTAfOCacGx7qq9on/QWPDZ5UNO8W0NnwRC?= =?us-ascii?Q?2r9L6L5OeMhraq0HWRhWrWi/KCrAtiHKfXJFhcZnctWaMwwVKvYmUbjKHFce?= =?us-ascii?Q?mozfoAh1dvdPIYPtTjC7iPkn1ewuFiV4Ow+27FQhdColedH99u2l8RIuHXeb?= =?us-ascii?Q?NyXLRmByGxqHoF9ZALW0U+RcS+VVwsmP78wQkqSZgqOgY2An16ydeJH5W80i?= =?us-ascii?Q?LM5zWMs0DirEltmTptBjV8157LJTxlZw3U/nLNLTcuyO4RtuMsG4xCfqhKTt?= =?us-ascii?Q?sDU4IeQtiyGjB3yyP6ritc3a+R/nJGjRlIt+dL/ldEqO1MoyPb1/5XZpv4yK?= =?us-ascii?Q?T2YaBbpRmYi0/Tq+1ITqx6aF7z6Fw1Kz6Ji82epBzhpCkcfXVoEuK8EpNZug?= =?us-ascii?Q?ALXWBXdp/ynVpEWXd8v5pWH1ryOAjVxiZl0coNzs3o2Yt+5iPQOTS9OMj2sn?= =?us-ascii?Q?iEsrfZZFH77mUrBhzym/UNGgsXLLYOlFvIkKebddH3BhOJ+HbD2DatubTgQT?= =?us-ascii?Q?oF4VPily2NAG9K/7X1cmEILzQ1U7eBen45GVx/uYeGZHXPmgOS85IxXfUUJ8?= =?us-ascii?Q?b6qaXPa1SkR68I5oQ1d3ISo/XIg/rP5X6QdSIdI3N9A9Iscizrmoeq4W31SS?= =?us-ascii?Q?s2A/8nuG3AAtccoiLFLNMtd4QHhg2bx4Ne3wn10EQYRDMTleutKbg/s+r9Vw?= =?us-ascii?Q?SodMoivNVPTjiR19QgJpWxYA2WF4NMSr2Zi4IQ/1vi6/IOaHwZ9D95bmV/12?= =?us-ascii?Q?qfAtT+skpcxpz1zF0GodKUNSkjDt1W+HgoJbgIiMQ878E4QRsPqm/E+Y7d6L?= =?us-ascii?Q?EPon7/GE5vxMgi3Az/Y1ONh7qYdBJ1aVArFVwBkAoRykIX1lbLXBkG22FlpZ?= =?us-ascii?Q?T8SaiocjCWRpA2E8089VTk7NM06RRGTusiksPqqcS9A9IcHJmkZgRLp22dqv?= =?us-ascii?Q?JxUMWXK+DZrMClhY7wVfsarZeLCRIqyjDYEXf+jMfWmEvZzwO/V1/bQFZo53?= =?us-ascii?Q?A7pIVO1UltXhyOKNQIbWGftdrPZOsCQ6d82sW0BgiHetdemETSGL2j2vQluA?= =?us-ascii?Q?oRKGBXNOMLfTn7ujWnnuppnQmPW2BMyRVWeFZyZicN7KZAz29OdA1Ia3mCAC?= =?us-ascii?Q?qVYteLDdHG9np0XyfKxTqlkL2O9XN68QOCuO4k8gkXRStOGgxWPPm9e1lsF2?= =?us-ascii?Q?6NnMgTmhelbGr2PrHCqU4iJUOGjZl1mLZQyqEfKrK54vQnn42Z8PCnJAGWoe?= =?us-ascii?Q?dKWfw2GW5ms0KcAID+zP3Ij20y9zotjrxp9xGeRc9eaOXZPLhfNJHeKxxj3T?= =?us-ascii?Q?G2cxm2xo9yBd/Ade1ute/PYnN4Xs7RssSdyv3FhrWhlEvCJKRU8v35to+Lja?= =?us-ascii?Q?cIN5o+OR17nZ6TXBVgiApbxttApDBSS5dW+0Q+4R27sN65DJi1qYYjgAvjoj?= =?us-ascii?Q?pAny3HbH33Pdjl6/IH60FuqruIiGL94RbSRQGo2tbfEoPBc15H+JJblhYrbO?= =?us-ascii?Q?GPL5b+LheG4+kzJ3gov2zh4Cr7sVelWUactLO1aH9w5mFo3EqPMZ/T+dI/fF?= =?us-ascii?Q?SwUwur0IF8oYvCfqE/QYabMKL1zEuO2JxdOX1PumuY69VMZF6Kpgsu6YbQ7K?= =?us-ascii?Q?qwTKeDoiAlixJbBdx4cRBPW6VY4qYUV8foBFvIPNVPt3iKmiuBaBGx4oQNSI?= =?us-ascii?Q?PxaiF76VngLITAXJ6LHwW6HiV8Z0xUt5ctoEqDY8jXB9vVdX?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5f46c334-9ed4-472f-fb58-08de5cc1d1f3 X-MS-Exchange-CrossTenant-AuthSource: DS2PR12MB9615.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2026 10:01:05.5972 (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: xPw51nCK3gACAxViLvAfcbm3ovujphewN50nRDvGDKrq/BA+iD9paTKvyTyvs3wGj4kG3Ie3NbHhhrmjo6nDNg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB8953 From: Joel Fernandes Updating "ppos" on error conditions does not make much sense. The pattern is to return the error code directly without modifying the position, or modify the position on success and return the number of bytes written. Since on success, the return value of apply is 0, there is no point in modifying ppos either. Fix it by removing all this and just returning error code or number of bytes written on success. Tested-by: Christian Loehle Acked-by: Tejun Heo Reviewed-by: Juri Lelli Reviewed-by: Andrea Righi Signed-off-by: Joel Fernandes --- kernel/sched/debug.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 41caa22e0680a..93f009e1076d8 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -345,8 +345,8 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu long cpu = (long) ((struct seq_file *) filp->private_data)->private; struct rq *rq = cpu_rq(cpu); u64 runtime, period; + int retval = 0; size_t err; - int retval; u64 value; err = kstrtoull_from_user(ubuf, cnt, 10, &value); @@ -380,8 +380,6 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu dl_server_stop(&rq->fair_server); retval = dl_server_apply_params(&rq->fair_server, runtime, period, 0); - if (retval) - cnt = retval; if (!runtime) printk_deferred("Fair server disabled in CPU %d, system may crash due to starvation.\n", @@ -389,6 +387,9 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu if (rq->cfs.h_nr_queued) dl_server_start(&rq->fair_server); + + if (retval < 0) + return retval; } *ppos += cnt; -- 2.52.0