From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=pass header.oldest-pass=0 smtp.remote-ip=52.101.189.135 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=pass; t=1794323648; b=bcFp7S9TeyqsxLgFN9eCm6KlejPAIeCQpFG8q9F7wHpR6+YglyJAt75IOfzL721LXvh/ KP33K/BrDMUAM9xbqM1VLwAUA6RJnQxe/2+olfA5yU0DlvcrTQuvczqUqZ+rD0Bo0mJHL ONQO2IBXAYOIWZiuez5jarqhW6svYhI3ufHub9ErR6pPL1Nm/BsYNKhuZnJvhw96Tm2xr Q3AAuugE9vKxmgMznXD5uuhwjrj+m8l4DnacGUDHdN+0dH3hnMryuIGAY/WYIm2s3TL/x al4DUrwb+AGvdj6iTRUBQ6rHhAFsnpzTwlIBT6+OhnIqv5GrxeRJHeblIv1bYA3gJYw== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794323648; h=DMARC-Filter:DKIM-Signature:Received:Received:Message-ID:Date: User-Agent:Subject:To:Cc:References:From:Content-Language:In-Reply-To: Content-Type:Content-Transfer-Encoding:X-ClientProxiedBy:MIME-Version: X-MS-PublicTrafficType:X-MS-TrafficTypeDiagnostic: X-MS-Office365-Filtering-Correlation-Id:X-MS-Exchange-SenderADCheck: X-MS-Exchange-AntiSpam-Relay:X-Microsoft-Antispam: X-Microsoft-Antispam-Message-Info:X-Forefront-Antispam-Report: X-MS-Exchange-AntiSpam-MessageData-ChunkCount: X-MS-Exchange-AntiSpam-MessageData-0:X-OriginatorOrg: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource:X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped; bh=XJF8w20/M5CvGkoGiiOWxIiX34yr2V1ilwsoDthVZCA=; b=rLXVw33vWye84MT5i0GY9EmabK8sTYa08PQezUXvl5NIObQq4DYiR7zXrmQljpqcG+rK +keyov/pRaEwMstwWcmVqwxC87daM+keCer4Wak73bpDE7RyEdzBcjCxk8t7n30MO5W+L U1QdRCI56MnmZBktEAx452tztU/lZA2P/CUFNSCBE8ytHY14jaNzTc4sLSprKtft7kKTP YiccektvWouH4wkS/WmlEn8iue9sj98G0N+wyiV/Gq7OvkKY9pJ3ngYALxK9KsP0tfteS y79zYzffXUIbpAkyEJ41CW1NAlUUPaawGIgOAXAIPUuBlJWWvO2jOpNrl9am5/Frgbg== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass header.d=efficios.com header.i=@efficios.com header.a=rsa-sha256 header.s=selector1 header.b=PU38j0yi; arc=pass header.oldest-pass=0 smtp.remote-ip=52.101.189.135 Received: from YT3PR01CU008.outbound.protection.outlook.com (mail-canadacentralazon11020135.outbound.protection.outlook.com [52.101.189.135]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (secp384r1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B4A34606A32A; Tue, 10 Nov 2026 15:14:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org B4A34606A32A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=efficios.com header.i=@efficios.com header.a=rsa-sha256 header.s=selector1 header.b=PU38j0yi ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=KIybOzOxBvaCCxPSlbKp0Picr9YeVasRI2J8JtRvANDkIEAbv76mXWsR4HfRE35U6fXy0Ds4scXPS413lBnrPvtvFFwEjevQzZz0oZS6LtnHlc/cxQOsk0QPDbu1/6A48uMrTF/YIo6dhlS+C5I16b3VuB3tOE2stW6IDJkT1ufFWxR9TDINNEfH7/ihnvegx3hDjsjxGT3xMHpwqKBzzfQfXKUWUxxrmffNMDiCO9YdTMy5Jv+Da+gTGqRmXfnyHwL/DedJWSh9Uf81/hesOKitu5KH2BDGfOWHiUYuo/mmAu5uPSplp+MzRz7XyQzq9Zl2YdaUBwxwBy5VsdA8Lw== 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=XJF8w20/M5CvGkoGiiOWxIiX34yr2V1ilwsoDthVZCA=; b=RdQeub+cWfQqXgi4LKSK6SERIE+wTd+Idl3luawWNJrxqisb8PljTPVVUaOgADtu7icUoGHA35vSfoRIp8iKzAzD9/UEbj+Qm90FCk7Uc/bXfPoLDYItu1fQPIkWfApj5uqmMS6J4uEiN+h65ORsyJu3FsL6U5HQthjrn+txolnqX4APDzthy/3tcRn/c2YYeuKiFfbInOCbCfC8DT73RS2DqcpuWFRQrSu1ZBWTnJbdlhY272rSB7weF2h/ejWI2AWX/NMNiMR4hJmu3dlxYfgv1RrPLMGjEsgZHU4P6l280wpbzsG23buTP0YLM2Sm9SxmvQ6T7Ek8R1Kmma4jgg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=efficios.com; dmarc=pass action=none header.from=efficios.com; dkim=pass header.d=efficios.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=XJF8w20/M5CvGkoGiiOWxIiX34yr2V1ilwsoDthVZCA=; b=PU38j0yinasi9fbpcxWB1okxwwPoZxh49uzu1d8ISk6q9mouU9uiQVm3Dk9ueQrJavG8mZBya5qu24FLZZX4woktDqPAdvzjbJu1a3KNm2516S6usMBxZRKr4rDR64bWw8xhMfWAYm4zY+PeOWNjLpcznh04mXowDjd/TOu4yaz9WPlaypaDUOt0aazk8OLri34teRrngWVR9k/SnpY827rHFD7kZqVJeO0cFDNk7+tE3StcZ3T3qqZ2O0lL6yDNic248tDeFtA8Ga82Wj2MVhhJgPr0Xbos9ddiO9mAsZAifkwrM0FYC5F3NNQZ4ye0g78HyqUxezET4nDcIdmvVw== Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=efficios.com; Received: from YT6PR01MB491026.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:1d0::10) by YT5PR01MB215679.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:19a::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.615.8; Tue, 10 Nov 2026 15:14:04 +0000 Received: from YT6PR01MB491026.CANPRD01.PROD.OUTLOOK.COM ([fe80::6b9e:a901:67c5:7ddc]) by YT6PR01MB491026.CANPRD01.PROD.OUTLOOK.COM ([fe80::6b9e:a901:67c5:7ddc%6]) with mapi id 15.21.0615.007; Tue, 10 Nov 2026 15:14:04 +0000 Message-ID: Date: Tue, 10 Nov 2026 10:14:03 -0500 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 10/12] rcu_txn: Test a commit from atomic context To: Puranjay Mohan Cc: "Paul E . McKenney" , linux-kernel@vger.kernel.org, Boqun Feng , Josh Triplett , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Uladzislau Rezki , Steven Rostedt , Lai Jiangshan , Zqiang , Linus Torvalds , Matthew Wilcox , Christian Brauner , Greg Kroah-Hartman , "Liam R . Howlett" , Lorenzo Stoakes , Alice Ryhl , Andrew Ballance , Peter Zijlstra , Will Deacon , Mark Rutland , Ingo Molnar , Thomas Gleixner , rcu@vger.kernel.org References: <20261016133319.433617-1-mathieu.desnoyers@efficios.com> <20261016133319.433617-11-mathieu.desnoyers@efficios.com> <20261023182218.479327-7-puranjay@kernel.org> From: Mathieu Desnoyers Content-Language: en-US In-Reply-To: <20261023182218.479327-7-puranjay@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: YT4PR01CA0126.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:d5::14) To YT6PR01MB491026.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:1d0::10) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: YT6PR01MB491026:EE_|YT5PR01MB215679:EE_ X-MS-Office365-Filtering-Correlation-Id: c705248a-26ff-4739-890c-08df3f3d41e7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|23010399003|7416014|376014|1800799024|4143699003|56012099006|22082099003|18002099003|10067099003|261022105027099003|261022075727099003|261028144727099003|261026140227099003|261026121527099003; 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:YT6PR01MB491026.CANPRD01.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(13230040)(366016)(23010399003)(7416014)(376014)(1800799024)(4143699003)(56012099006)(22082099003)(18002099003)(10067099003)(261022105027099003)(261022075727099003)(261028144727099003)(261026140227099003)(261026121527099003);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?YVZmRXR2R1d4MEpuYlZzcUw2VGhUdzhKYi9ibjdCNks1WlJ2YU1XZEF6cElU?= =?utf-8?B?OUN6UldnajlieFlIZnIzeDVRdFQ2VTR6Z0VFQ1ppcThGZjNRbDBoZVlQdmo5?= =?utf-8?B?VEVaUm52MnVJZkdXSVJUN2lWMjFXQmJCV0czWXpWMVdMTGdma3paYjFlV21t?= =?utf-8?B?OEtIT2VGTUlXbHN5Um5rYTVMWjhJUGE0bldVTmF5VmR5SXViSTgyVVVOM1dq?= =?utf-8?B?US9UWEZnNDlid3Y1ZEVSRWVPUTgrYWxCTmJGRDBSUFZYS0ZLVlpNUDlvQUZ2?= =?utf-8?B?Wkx3bm9hNUhNK2ZBR2VNMlAxbWFYRGNhOVBUNUJlV3p1STNPR0w3YVV4ZEZK?= =?utf-8?B?NzV6VDBVUWtncTZ5NHZmek1XRDUrYzdYOTJGL2NObDBqWSt5ZUtLdXBBeERy?= =?utf-8?B?bnRaam1ZS0ZRZHRPcnJlQUwyMldVVzRZRWpDbDFyTTNzL2owUk5GWEc3cVNP?= =?utf-8?B?bkNTd094K2pqcmx5cXdnbkVQcGhZeE8rSTlWWmthMzYvblB6Sm9pYjlwYW1O?= =?utf-8?B?SzhUUWNWZTY4WXRnWGFMZEF1eWRkbmZBbCtZYzNHY0tRWDNIYXpFMVA4Y2Qy?= =?utf-8?B?eDc0OTAvNGdjV0hQZ2FZWFJvTTFlelFXYm9HQkl3dXpBUnQwT0dGRGtmKzZE?= =?utf-8?B?VGp2N3gzSU44TGFncWhRY1BJbUVjT2h1dU9ybTQ4S1c2cjNDbC9qWmlLYVF4?= =?utf-8?B?cFZBQkJRaCttWC9TNHdqMDEyVnhjSUhmK05wQVdPcG92YW5rYlU0SSs2L3lx?= =?utf-8?B?akw0RVZMUFpXQmVEU29ydElodk0rVGNDQ1N2T2QvYUJ1cWZpRU05M01oY2Mw?= =?utf-8?B?S1NPY1BXRkV4MHVueTVEQU85N1g3VHBRRVBWNWVFT0x4SlNzQkdBYlNObVVi?= =?utf-8?B?ZWJuTWFGczVBWmswaGpXYXM0eVVxZEFqNy90VTNXZFJOMlZqRjJmd2tMUDZJ?= =?utf-8?B?aWllRFhMWHJaejBuVSs2cVY4QVJaZEh0Y2RHVXBkNW9WQURzZkthb3hNL00r?= =?utf-8?B?YUZwdnlZWlkwOWU3eUhzU09lanQ4ZXIrbUpkaVgvMjBqTmRjaU9pVUZJa2Z4?= =?utf-8?B?SFcwaU9DbkVmT05SVGJmZjNwTEsvVld0S0lVRk1FN3owd2FKQUp0WEhiblYr?= =?utf-8?B?ZUx4ckgvRlpGMmNieTQzakxqUTFaeEtrU0R2azMwblFxN2puUy90ZWtoNUR1?= =?utf-8?B?SFplS1MvUUVrc2srTXd1SUtFQjNVblNJbjdlMGx0QnNQQWlRR2pkWms5b3Zy?= =?utf-8?B?YlVQNDFGRkRVcVh1SjUwcmt2bXlTTW55VTZIQWp4bFpmaStKa21mYWpuRHRy?= =?utf-8?B?VzI3OVMxaWdHdVlpVmkwUXBkdVh1T1FHbjNnSW5zYzM5bTNtb216UjZHSTlG?= =?utf-8?B?b0FTTDFMazBsZGlGcStDMVpyakwvRjFJVmF2Z1ZmWkRxdmdMUyt0MFRtUHIz?= =?utf-8?B?WVhmaE1kY1FNKy9lalZ2Z0prck1ocUZKQWt4b1orMEJmR0hVUUtNMGR3d1NP?= =?utf-8?B?cHdKTVdWTXo1aWpoYW96UVhaNGdMZThvVlBPRTEwOFFSd3F3WXBIdFAxUjdi?= =?utf-8?B?WUFpR0wrbDlUcUtOaDdUSWhWR2ZKMmRmVHNMT2pxVDJQTkpiUld1ZkpkYTVY?= =?utf-8?B?MWs0aU55TVFJZGZXWkFBZWVPZ1BRL1lCTmxLU21nUGcvZ1NtMFBnUmx4Szg5?= =?utf-8?B?dGpmUHhsNkFPUndPMFg0SDJISURIblhVZVVNaSt2YkxQc0t6U1FHckR1Y1p2?= =?utf-8?B?Qlg3ODc5NE9KZkx1VSs0S2VmYmJoQTBzUHNjd1VQZEpFbWV1amJZQVhJMEVM?= =?utf-8?B?ZllQMlRQcnBoYWpNbSt4K09TMmVqNENIclRuVWlWMnBFTlJmaWFPdmtuMXlM?= =?utf-8?B?SjJGK3FpVVlNWXpPRGpQM3I4blBXaklNTVRPL1ZWbDBVZ1kzRzltSVBHa1B4?= =?utf-8?B?YytQNUhSWXFXc3c4cmlCUit4WFZKdmlydnhTWXNUaGFiSzYwaXgxN1RNMUk1?= =?utf-8?B?Mnd6bGhlUDJuMjM4T0hxamJFTzBPVlpma2w3ZDhDbkcraFVGNWRHeWFlQXlO?= =?utf-8?B?RkVjZ1E3NGxkZlBSQmpqMzJlbERRRXV3L3Q2RE5Sd0wyZldpR3p5dE5HWldW?= =?utf-8?B?ZEl6M1JkQ2k0YSsxSWFZTnhDdHFLRmdlMTB6KzV6NjNZSVN2MTYwTlVmTXl6?= =?utf-8?B?Umo2SHpESkVvMks2R1A0VWxFai9GTThKYVlhVU5GdzQ0SDlLTi9XZzJKOTM0?= =?utf-8?B?cGtQeExyUjBhREMwa2hBTi9jQTJFRC9tMUpXWlNPMlNMcEtGY05SYXpRRGNF?= =?utf-8?B?VDEyVC96ZU1jWXJPMTYrU0Uya2RkZURiZS9OMGEzWTdYVkwzTjI1a1prZkpZ?= =?utf-8?Q?iGP1PHl4EM45gKNm9ejkqyYy3/iNCkmkxd8zX?= X-OriginatorOrg: efficios.com X-MS-Exchange-CrossTenant-Network-Message-Id: c705248a-26ff-4739-890c-08df3f3d41e7 X-MS-Exchange-CrossTenant-AuthSource: YT6PR01MB491026.CANPRD01.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Nov 2026 15:14:04.2011 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4f278736-4ab6-415c-957e-1f55336bd31e X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: lFD5DizEYvuao9hKYaixsKiMO9kS4EQ+dXNXl8zqMJs/oajCIRHrfTTqQAqt/B/JrV/nYwPK/3tk5BbO+MIKFpEABP6UtSSxrm7mkO4pD5M= X-MS-Exchange-Transport-CrossTenantHeadersStamped: YT5PR01MB215679 On 2026-10-23 14:22, Puranjay Mohan wrote: [...] > This matters on !PREEMPT_RT too: there, a one-record commit or a cancel > under a raw spinlock calls kfree(), which lockdep can flag (see my reply > to patch 1). The test can't catch that as written. Agreed. The next version will fix the free in patch 1, and this test will catch it. [...] > Running the one-record and cancel cases under raw_spin_lock_irqsave() in > a loop would catch it. My first try reserved and committed one handle at a time. It did not catch it: each kfree() gave back the object that the reserve had just taken, so the sheaf never filled. As in your reproducer, the next version reserves 4096 one-record handles first. Then it commits them all under one raw spinlock, and does the same for cancels. On x86_64, this gives your barn->lock splat with kfree() put back, and passes with kfree_rcu(). [...] > A kunit_skip() when PROVE_RAW_LOCK_NESTING is off, or > debug_locks is already 0, or TAINT_WARN is already set, would make that > visible. Planned for the next version, with these three conditions. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com