From nobody Thu Apr 2 23:55:49 2026 Received: from mx0a-0064b401.pphosted.com (mx0a-0064b401.pphosted.com [205.220.166.238]) (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 B7F6623183F; Sat, 14 Feb 2026 19:33:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=205.220.166.238 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771097632; cv=fail; b=Q6wN/yYM3Y1wPtRAxrSmhPVt4YFFhCz/xl9LF1YerKiCpmblrdFTNhiUFO9+mPH6BhBgi9tAwc4eSAxZz+acHd7vJbtqDd4Qsz4X88Gl++qrpbi9e7fyjvPV/zLRspOaRPvVhGSal6ooh/nJv1y5qXsdwEILIIIEu1Vj4yb8zAw= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771097632; c=relaxed/simple; bh=Dl0hwCWMgGb7PQU+8zGk8VYU+BYEs7s09q1g1Z18GMU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=Uvr1an3vXJipIKd/QiRQwj15SIyFjVh//b3YhyzOYMyW0vgfag4hLQANKuW2yIJSWSf7D8L7ySGWCJbUmDdWs7z5aNJL8C1oC92kq78otIPK1cxZ77wK7EKnhlvSFbwjgiUGCaZraS9S8R2dsN/EC7NgrwZcVAqcZYqT1qE5b+o= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com; spf=pass smtp.mailfrom=windriver.com; dkim=pass (2048-bit key) header.d=windriver.com header.i=@windriver.com header.b=h1Z8g7gm; arc=fail smtp.client-ip=205.220.166.238 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=windriver.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=windriver.com header.i=@windriver.com header.b="h1Z8g7gm" Received: from pps.filterd (m0250809.ppops.net [127.0.0.1]) by mx0a-0064b401.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 61EJK1aD1024949; Sat, 14 Feb 2026 11:33:37 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=windriver.com; h=cc:content-transfer-encoding:content-type:date:from :in-reply-to:message-id:mime-version:references:subject:to; s= PPS06212021; bh=JcMkbpOC1uAJ1YlzyTspHYrJuZRirw7GYwKjB7tXR7Y=; b= h1Z8g7gm5nxU7BkUIatlIxWWsQeSBqG1nH8Om5ndqQUN3vmvd49McXLcgJAHNBMc kKJ4l+Q58z7zGJljcmihc3/AEgr+jTnjhWJZ84DdaLQ3OnulkJTF+u0P9KGktIg8 hj+rT/TgZfq0vw3cU3pXo6eIxPBMsCwfWK3Sh4wMfbY0rRCaxJBTa/ZLoAg4kwA0 Ohlc+aiZkVao/qdk50Aw0gTDOtkFVUFV5KsOaIy81L9D8RqkmePdL5LOXGShD6C+ bEJqbyU+JRUKU33rtZufAQ2HsAHa58vrVZnFJaHrx04oJ4mji0JJwccnHKudT0sz GjHjUkhv85z2Ko+Bob+6Lg== Received: from sj2pr03cu001.outbound.protection.outlook.com (mail-westusazon11012011.outbound.protection.outlook.com [52.101.43.11]) by mx0a-0064b401.pphosted.com (PPS) with ESMTPS id 4casehg6jy-1 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Sat, 14 Feb 2026 11:33:37 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=yHicOYIH0rhXidjwabwOwibCKpMyoeANgIGZ5Wnq8jVKWeda12gol4ZpvbRUENMg3K3iFdIVzcx+9quf6MhYQa0Hw4bicJRxscB0ZzdaDpGEDnosbs2chO7xw3gUHLrIOc2+Eg5SBqRaTXPWTtdPk6XOK4G48r8noL1HDWwGqGvngkBxJuCsXMVuAqsw/gZabNY/97YmYOBdc00supacbs2sGshUQ4Kr7Ki4icsE5SjWgWUcINzDXDxPQRbP6i9lKmztDVlPZlbjr4QabA0XRvr4VQATR5AfPi1rWEWKIkGyrK6Uy9hKpaKiUSR8EwzIojqhNAhkJPTs9HQQJASSXQ== 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=JcMkbpOC1uAJ1YlzyTspHYrJuZRirw7GYwKjB7tXR7Y=; b=fB5NmkK+faKg+4pzDyWpYVYldUEIb+bNFPms9bTp+PfWa7udkE4cuJrIKIZ023vlipJtj1pz5qt50GinM/0BMnbEAQAisnWudlyhf0ZaSMsGjkqf7egHR2Z4lhT9x8BwdN/g6EIBSYXR0Mte9TYmdVmoX2O7xvGV7cxaSb6w4jYG3sP49GXCegqhGAFcZsrGKKWsH554huUGMFiUV156h/u3ckb+/DS/aQpRiSl4cLz7zCBoVLsG92fwhxePNvqmG4AB73EH3B0EXtDLbhD+ZJdlyF8ew9kLaUgvc9itwyKan4lRnJHZvdBKZ/7qTR+KwI4fCGtxBwVItMbzCefdgQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=windriver.com; dmarc=pass action=none header.from=windriver.com; dkim=pass header.d=windriver.com; arc=none Received: from MN2PR11MB3885.namprd11.prod.outlook.com (2603:10b6:208:151::27) by CO1PR11MB5044.namprd11.prod.outlook.com (2603:10b6:303:92::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9611.10; Sat, 14 Feb 2026 19:33:34 +0000 Received: from MN2PR11MB3885.namprd11.prod.outlook.com ([fe80::a8bb:9703:986e:845]) by MN2PR11MB3885.namprd11.prod.outlook.com ([fe80::a8bb:9703:986e:845%4]) with mapi id 15.20.9611.008; Sat, 14 Feb 2026 19:33:33 +0000 From: "Ionut Nechita (Wind River)" To: Bjorn Helgaas Cc: Bjorn Helgaas , Sebastian Ott , Niklas Schnelle , Benjamin Block , Farhan Ali , Julian Ruess , Ionut Nechita , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Ionut Nechita , stable@vger.kernel.org, Ionut Nechita Subject: [PATCH v1 1/1] PCI/IOV: Add nested locking in sriov_add_vfs/sriov_del_vfs for complete serialization Date: Sat, 14 Feb 2026 21:32:37 +0200 Message-ID: <20260214193235.262219-5-ionut.nechita@windriver.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260214193235.262219-3-ionut.nechita@windriver.com> References: <20260214193235.262219-3-ionut.nechita@windriver.com> Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: VI1PR0102CA0073.eurprd01.prod.exchangelabs.com (2603:10a6:803:15::14) To MN2PR11MB3885.namprd11.prod.outlook.com (2603:10b6:208:151::27) 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: MN2PR11MB3885:EE_|CO1PR11MB5044:EE_ X-MS-Office365-Filtering-Correlation-Id: 2debb0f4-0282-4d5b-f94a-08de6bfff0ff X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|10070799003|52116014|366016|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?hSHqQ6KRomFm/QwOkCCqxXMQ+gOePjRg0I3Ed0h6NI3GCvS2hpNlUYsvF75k?= =?us-ascii?Q?AyYPpABJAvll/RWhWESyoBtxlECA+tTPzmJfghECHyzoTb+VYq2mhEk39xiT?= =?us-ascii?Q?UaxHv5Tf8rS0sds47SPsGP782W2Ux8IN46LEBgkk5WqXuWzZPcqoPhPGsb6t?= =?us-ascii?Q?wDuBwt/rilFdp2OL8k0mpfQfcYza5MnFHOZtrJTi9jeT4Yqgzx3zKfWLqsP+?= =?us-ascii?Q?Yi2S6jU9gQ4X5zckarcvm6moy0SbDPGNhXFZiq8QzRoiocRhAVSkwr6RKe0g?= =?us-ascii?Q?U1vUVPPIKfH8o84tPMy1L5JzmL8lwu6a9smJgSS9Auc8562ndSPY3/qc+M4N?= =?us-ascii?Q?bWceLRL6MoRC7rvFdhALeaRZrMuGunTTbaU4E4CEBvtDaQAqF1l/g5LmpF9U?= =?us-ascii?Q?t/+7wMVY5I1IkT843ysBT6Qcqo8cZDgdtimd+pj25wbtaABv2R+hY46NKUZ5?= =?us-ascii?Q?PjnObzNaYVyoW4IJ73qlguntOeiH2upXasDRchJVF6Y/X9pLzE4zp2x8RAWp?= =?us-ascii?Q?U2u5+k5mLKB2+fveV+JfrsT7FKd76iKq7sbhSkDBU13yOqWQ/dQpTk5d10V4?= =?us-ascii?Q?Eavn9zwgUczn1pPg9ucv7fEc9q1S2Xd57OzRROs/FcIs+FDs4WWBiOWhnffy?= =?us-ascii?Q?rjC4jiOEEOOOo0AAdiWhw61ILHS+efhPO6JRldVlR17P92F4vylvt7DMrlWk?= =?us-ascii?Q?q9Lbz5L9gIqL3KB5vJOKLhN+vZCTJxC24eE9k103unMAGGMT2KVSRrBJwZJf?= =?us-ascii?Q?U7FX2PtmJG5QzHRduQlA2osLPscntqm2qg1pbsoaVfm8YTk3OFYeVHr1DTjG?= =?us-ascii?Q?AVQRxUAlkReJmaXrcvdrcBkGNMVsWXajVd5wEsZRbPc1vvRVP/t4KyoIDCum?= =?us-ascii?Q?8WkxowAqKLU4FIv7f1P2tn57kHAMKPs7dz9Y7KFGBzfhJB62pWT82V6WSz41?= =?us-ascii?Q?WvTgWyLKLg/uLdCltI2dzZWA99+MiD1nOByyqSjXATKpoa+q+S4RljixIOdx?= =?us-ascii?Q?TpTRLrApwE/DfyLYwUCiitbqEmqnzP8W/CYT5FG2alz2CFW8ss3KJwk2+i/u?= =?us-ascii?Q?dImSsjOwLoIQVq+wlTDAmrOPj+4ayRp4ZsrpUT5wxkGXFcWKaaEnwoeT1rSU?= =?us-ascii?Q?aitw9y+m+V0n++pUtQHOvCbM8gFQtl9GPg3SzsmQ6kk5GJVavwJyqI1I/aT7?= =?us-ascii?Q?aaZxysCZ7ugSq8/QOrd254xBeiY49m+OORfUTPozBV7JcUlyuLUY5bKktg5h?= =?us-ascii?Q?/jv75ch1uzevVPoTB0EHXw5ILJbx2wS37lXJTNCXNCSOgCmFMbP0YrYQN+HA?= =?us-ascii?Q?9scmE0mhSR6MJm4jcQJG0jchg5/X7Hwb7+Y352RjigArlRvyrYFHiz8GKc+D?= =?us-ascii?Q?B4ItYZsn4g91I6e7EWyDGyfdzrbafyT6iEjFsVj5ot+ek7gEAhN3r0FS5mmb?= =?us-ascii?Q?uoYO6yid33k8bMau63D3H7TyYQl/qvgTGvzfEpIE3ExsEcOPFvg2GQ0kLPkd?= =?us-ascii?Q?SZ6yZy0WoO8rv7TrhJgqQR/R+GTVX7eUkkIgJGJL1Klk3B8/iscuQUCDbTul?= =?us-ascii?Q?c0IIHz3pVcwAFok10Q0=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR11MB3885.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(10070799003)(52116014)(366016)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 2 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?CNl8HtUv+t6J2rzQAKqefUvKytoTpB/V4SVNDuWePwhOhKBTpzqqxw03l9M8?= =?us-ascii?Q?7X6NnK2HZXd5fDfMDCdS3qlFwTJ0TocKL7ZSDBuOuXzMKjn+fIpxjegHbzhr?= =?us-ascii?Q?KfixXMQhVXc61vzgWC/epuwobDF4INR67M+KfznTaLEe5pQzrh2rfPlCAcV5?= =?us-ascii?Q?srGGHL9roNFW7vmVPBzFh/pW+CsJQw/IQW4Swu1977YrH/Spnm7D/q8TdeRP?= =?us-ascii?Q?GEuEXyHGOGGcvwNEqWaedDlErJH5Ozca1stRQdR6VsrtCi3/S9eJhQIBCvty?= =?us-ascii?Q?3yedfr5/1mcuqTaVF1kh4AGuOL0ypvcZ+1byP52ohRT7dh2TMN7KW9EkH0EY?= =?us-ascii?Q?IIW5Xm0HiOUrcx9fNp9QZWCpMnLBAGE9oSl/99uFzgVpmfuUURGvyW7vdFM4?= =?us-ascii?Q?xZijF0af88lvE9kzY2j8ho1oYDA43WGMOg5xFauDYJxrtAJUjTvL1F1bbcWj?= =?us-ascii?Q?u01dbRxmIuLqdBH9vg9WvYX4fAwUFNMgk1K4q9MjKk4cIUYyQgdWd/aZv1IB?= =?us-ascii?Q?ilixqFchOBGh1H5y2ziAQtjvYjATZl6pipBokkAgEvv41AmUR40NzGImvKCz?= =?us-ascii?Q?8e71Js+xt9cGaMSD9KC1BU4nEwHgzOi1EsJdLyhB0alwKfhrtt6felmr6dum?= =?us-ascii?Q?bO+GZkrOEmeS8xMvbHGIx+Yvuiuo406GKjm0DTuChPsYjW1y31FqgzJBV6VB?= =?us-ascii?Q?181Ba1Votvsg18Af1DyKWE4Z306lhcv3H6cGHFKq9MfoFycEdtUWWkBwFBWa?= =?us-ascii?Q?YvtXtaNXfJwBQapRCIObgbACmvQ4TkqrU89EOy2fY3reHgG/zHJ2Ssu+hTsx?= =?us-ascii?Q?alp/Dia+0GlwrI4jpVbqYPFQtsbKSKKH978vdCrJHqsvuqYjmhcXjik2mSl9?= =?us-ascii?Q?1PoQGX/Y2h0LRHjz07KX8Ub1v341yvG6/356mHFOFp4OrP5eoX7gVS1R+mLk?= =?us-ascii?Q?ZXWvp9gNKfBk6bQ/5XAPsjTj2PycKLQKFK35I/VLDbYVvZh9p33odWo61FpA?= =?us-ascii?Q?DOB4FY+2RjsBIkg4E/I43/0hC382cJmetfWDYfpIZ8pGE6Eug5VVSE5YWn0D?= =?us-ascii?Q?WSbeExBj1d89jd18pWr9t7doCBBzQEv7VSrNiGdvu06f8VAaOl0rLwzH4Rod?= =?us-ascii?Q?3aZVMGW3c/WX/K1AjEBNwYGcrvdTld+pG/lw8GaYX8eEtItZjaq7RmVx8NNp?= =?us-ascii?Q?sfuh6XYiA72RJrGBukG0gkLs7snzOOy8h9K6DQTFg8VSiADR+AZ0z3r24+Na?= =?us-ascii?Q?rHMZy0OkVG44VBQwbf2zP4i4OUIzD/qSj3D6iIQzrRXhS/MpRaPzaGbLHbGJ?= =?us-ascii?Q?ZlPVoR49sTkUDDii/GMzLHu79hUC7A/ZmD5d4EFw6KtG00RQc29BSlk7BJc2?= =?us-ascii?Q?g1GhrRa6QlLKokTTQzN/5c+HAIKj/2OdE1wCHwHChfDZlOg9ngSoYKbNUHUF?= =?us-ascii?Q?lWPYDay15AhxbD1ynY634eWMA2xwuWcRey2/wXCBmP3BrlcKH4I/BSf9BJRD?= =?us-ascii?Q?oqpbUxG202X0+6HIp1EVf9bf1SxsG5/d0EgfX7ppR35gQaiUENCVdi/s2xT8?= =?us-ascii?Q?CZi273pvRdV+mE9zfRE4Z28UpVTn55L3n4lgZRe7TcOv42Wg8pSm59oz70nj?= =?us-ascii?Q?rgrXV8fG3l/+xaDgI3N4/EmVzP8vvXUK8NLaqWmvjEqgIOkExQFViDw82FT+?= =?us-ascii?Q?NB4GxgO+QiCltgpQh9IZ6NeKNVTt/AZEHFg8GK600mTLiRCFqOOLGYsxk6Sr?= =?us-ascii?Q?z95aOLFrBy/2vTytAPvqSyMMIgHG1V/e0Z+47kmIoWRC/gDTwWUDzJHJ6WAs?= X-MS-Exchange-AntiSpam-MessageData-1: 0QpyY/9KYLtn4TDEXXDzKujXIaWJdRMJGmY= X-OriginatorOrg: windriver.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2debb0f4-0282-4d5b-f94a-08de6bfff0ff X-MS-Exchange-CrossTenant-AuthSource: MN2PR11MB3885.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Feb 2026 19:33:33.8804 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 8ddb2873-a1ad-4a18-ae4e-4644631433be X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: nyEmStleWWks32rfnrDy9CqXAxydQpXcOCrckZqLDdR4/5u7peGNa7VSqdoXIp/QlUtixee5iksTCT9qo4gRtxyOFJrturMK2Gpj6xJ63Cs= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CO1PR11MB5044 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjE0MDE2MyBTYWx0ZWRfX9y6InFIXSLb4 tQFrpGV60+IKuuE7fcUjFGHGwmtrp62m0ula+GqCttbK1vwa7xoJdupl/EF1fj/tycBr8N4lNOd a28bjsrHlQTMP5W6tVgPhyG8NnDvZv/TIa4k7G1KLm6KDCn164ZsKPiPpntDZWwIccZ4r7sy3GU ZqJgooT0KNtYpoLJPLsipPXYxQBnYT5+4PcOsEagDlj9+bVvzhH7VWExHyMqqbX+FuPAaB6vqCe /V5jY/rjhYE2q+6MAWO4FEG0c5f4+4T362DPrfma9a2Y3YvZlWoU8bzE9bZfhkm/K1oU2pQbdKv D71Xb28GFeTb9EqfA/qg04rfcIiOJPLoTs/M/wVVo+UyAsM3l5OfCCzoybT3NldnVeqMaDFas2a Lj6ucoszpqdAJDLC4gU/TsVdHQz5H1udjkLdsERL5WXT+atSZqJeQzFql5oUE65E7wBiXnMDW7t gIUOC+OwEnq//gUpdxQ== X-Proofpoint-ORIG-GUID: d1WJwzjFOZl0sfXA0j8JAHoCcPtvvwRT X-Proofpoint-GUID: d1WJwzjFOZl0sfXA0j8JAHoCcPtvvwRT X-Authority-Analysis: v=2.4 cv=Fek6BZ+6 c=1 sm=1 tr=0 ts=6990ce11 cx=c_pps a=/yS4kdDgObtqNMJizKN72Q==:117 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=t7CeM3EgAAAA:8 a=VwQbUJbxAAAA:8 a=CjxXgO3LAAAA:8 a=6S3VQf3ZLieD-afqmuUA:9 a=FdTzh2GWekK77mhwV6Dw:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-14_02,2026-02-13_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 lowpriorityscore=0 phishscore=0 priorityscore=1501 bulkscore=0 clxscore=1011 malwarescore=0 suspectscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602140163 Content-Type: text/plain; charset="utf-8" From: Ionut Nechita After reverting commit 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking when enabling/disabling SR-IOV") and moving the lock to sriov_numvfs_store(), the path through driver .remove() (e.g. rmmod, or manual unbind) that calls pci_disable_sriov() directly remains unprotected against concurrent hotplug events. This affects any SR-IOV capable driver that calls pci_disable_sriov() from its .remove() callback (i40e, ice, mlx5, bnxt, etc.). On s390, platform-generated hot-unplug events for VFs can race with sriov_del_vfs() when a PF driver is being unloaded. The platform event handler takes pci_rescan_remove_lock, but sriov_del_vfs() does not, leading to double removal and list corruption. We cannot use a plain mutex_lock() here because sriov_del_vfs() may also be called from paths that already hold pci_rescan_remove_lock (e.g. remove_store -> pci_stop_and_remove_bus_device_locked, or sriov_numvfs_store with the lock taken by the previous patch). Using mutex_lock() in those cases would deadlock. Instead, introduce owner tracking for pci_rescan_remove_lock via a new pci_lock_rescan_remove_nested() helper. This function checks if the current task already holds the lock: - If the lock is not held: acquires it and returns true, providing full serialization against concurrent hotplug events (including platform-generated events on s390). - If the lock is already held by the current task (nested call from remove_store or sriov_numvfs_store paths): returns false without re-acquiring, avoiding deadlock while the caller already provides the necessary serialization. - If the lock is held by another task (concurrent hotplug): blocks until the lock is released, then acquires it, providing complete serialization. This is the key improvement over a trylock approach. Fixes: 18f9e9d150fc ("PCI/IOV: Factor out sriov_add_vfs()") Cc: stable@vger.kernel.org Signed-off-by: Ionut Nechita Signed-off-by: Ionut Nechita --- drivers/pci/iov.c | 10 ++++++++++ drivers/pci/pci.h | 1 + drivers/pci/probe.c | 12 ++++++++++++ 3 files changed, 23 insertions(+) diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 4a659c34935e..38372ac0e2ad 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -629,19 +629,25 @@ static int sriov_add_vfs(struct pci_dev *dev, u16 num= _vfs) { unsigned int i; int rc; + bool nested; =20 if (dev->no_vf_scan) return 0; =20 + nested =3D !pci_lock_rescan_remove_nested(); for (i =3D 0; i < num_vfs; i++) { rc =3D pci_iov_add_virtfn(dev, i); if (rc) goto failed; } + if (!nested) + pci_unlock_rescan_remove(); return 0; failed: while (i--) pci_iov_remove_virtfn(dev, i); + if (!nested) + pci_unlock_rescan_remove(); =20 return rc; } @@ -764,10 +770,14 @@ static int sriov_enable(struct pci_dev *dev, int nr_v= irtfn) static void sriov_del_vfs(struct pci_dev *dev) { struct pci_sriov *iov =3D dev->sriov; + bool nested; int i; =20 + nested =3D !pci_lock_rescan_remove_nested(); for (i =3D 0; i < iov->num_VFs; i++) pci_iov_remove_virtfn(dev, i); + if (!nested) + pci_unlock_rescan_remove(); } =20 static void sriov_disable(struct pci_dev *dev) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index c8a0522e2e1f..7d3b705728fd 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -367,6 +367,7 @@ static inline void pci_remove_legacy_files(struct pci_b= us *bus) { } /* Lock for read/write access to pci device and bus lists */ extern struct rw_semaphore pci_bus_sem; extern struct mutex pci_slot_mutex; +bool pci_lock_rescan_remove_nested(void); =20 extern raw_spinlock_t pci_lock; =20 diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 7711f579fa1d..5f38ed0c641a 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -3478,19 +3478,31 @@ EXPORT_SYMBOL_GPL(pci_rescan_bus); * routines should always be executed under this mutex. */ DEFINE_MUTEX(pci_rescan_remove_lock); +static struct task_struct *pci_rescan_remove_owner; =20 void pci_lock_rescan_remove(void) { mutex_lock(&pci_rescan_remove_lock); + pci_rescan_remove_owner =3D current; } EXPORT_SYMBOL_GPL(pci_lock_rescan_remove); =20 void pci_unlock_rescan_remove(void) { + pci_rescan_remove_owner =3D NULL; mutex_unlock(&pci_rescan_remove_lock); } EXPORT_SYMBOL_GPL(pci_unlock_rescan_remove); =20 +bool pci_lock_rescan_remove_nested(void) +{ + if (pci_rescan_remove_owner =3D=3D current) + return false; + pci_lock_rescan_remove(); + return true; +} +EXPORT_SYMBOL_GPL(pci_lock_rescan_remove_nested); + static int __init pci_sort_bf_cmp(const struct device *d_a, const struct device *d_b) { --=20 2.53.0