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McKenney" , Kunwu Chan , "rcu@vger.kernel.org" , "linux-xfs@vger.kernel.org" , hch , Thomas Gleixner Subject: Re: rcu stalls during fstests runs for xfs Message-ID: <20260220190142.GA2120005@joelbox2> References: <13b25e07-d7b8-4b4e-a249-b6826b2eea39@paulmck-laptop> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: BL1PR13CA0202.namprd13.prod.outlook.com (2603:10b6:208:2be::27) To DS0PR12MB6486.namprd12.prod.outlook.com (2603:10b6:8:c5::21) Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR12MB6486:EE_|DS0PR12MB6629:EE_ X-MS-Office365-Filtering-Correlation-Id: 7dae80da-4bef-4fe4-4aa3-08de70b27ccc X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?q5phgZagquxIRQ1xSxr5CMEg1FF0Q5CXPOMablKlrih/Q2TzCyXQUVDrSwqs?= =?us-ascii?Q?dudkmR46XpzHu8Ti3lMz3qrRjo/i9abjboTiCp9M3tCcKSwg6AXvZRsvUg/1?= =?us-ascii?Q?DnFS1TbBpmQbbdnN+9YHHFvDh50AZNMdEwWCsdxseR4D+xN0/CN7CYTAMfiq?= =?us-ascii?Q?hQJe7VduxquN9q/3WZ+9mWvIfnTACH3zT81LS4e7/0eHNcWNCFwdxv2DKu9a?= =?us-ascii?Q?NV9eM3PWraQ0TmUQk9TQKEXI5Ro63m+hkXujrJqvs0fB4KC5wORsomPBlTa2?= =?us-ascii?Q?/F98JCDOj1rzA7P7uK+Saw+OK7ISQjS9v1Bf254CMUx3NbCOpW3Q/X87HQVc?= =?us-ascii?Q?rOjw+faBg7mS7G29dMCh2NfjCOgA32gDe9kqlKoXqRc/VIemTeQmKOOa0uP0?= =?us-ascii?Q?+VgLGDWJAWeeFCh3QuM7KLCka8V4UN9mdX+hfZ1sjxpFCLakbRSXCtj+nCmC?= =?us-ascii?Q?nJT7wHJuowH9YSkpSbefKp3vkuJilaPt+3pbF1Nf3M4Nt7qHEXzsSpKYbndM?= =?us-ascii?Q?wBZFsFJYv+ziX4KZXeExC9PmL1G/rmJweE+AlKSYOUBHPaxdlZR/k9JCPZfj?= =?us-ascii?Q?+KAG/bHs0M2SBuy5NOEFgN42VFb+ChwJXtGEdgW2Y+RQUrjSzVz18Y2qy65y?= =?us-ascii?Q?Ylkth4jm+otRx2INQIn6aek3nEGZcrvDYT8+HUEHhzY49hpdn3MJMKU7gzgb?= =?us-ascii?Q?0pmr9FqC1ydpQuPcHv04puFYLtm0yHleEeMtv6mSXPDMDLBy8EdwOYWLbHZR?= =?us-ascii?Q?lEDSvtu/SzmRl5AfWNB4UOgVmVc26qhTHZjUzgHupFZEA77YC5eET/gU4lLm?= =?us-ascii?Q?34pVjGfEVhe7vD7VYPxemo63Whv+VVm4UmftQXX1dvdLARczCnItuDpS/+jH?= =?us-ascii?Q?1gUo0CA+meEJBNTOWPwfex3Lnlcarp9ql6a1FrOKXBiPCCChRjslj119WovG?= =?us-ascii?Q?YqSh0tBiCUHnYssvAH46MAh7Z+dPK9rNtQS2/VCdanlZ1Qw+NL9UuQc+KNiw?= =?us-ascii?Q?H1ZyHYnWqqTtHHBU3eBcawdETplL2n4f5jSqmA8YdhepDmXpuwWcdYvSHUNP?= =?us-ascii?Q?FoiZNByznpLeQIgeh2SOGd3jmjEg6gKkx2NigbC+XEuTEXrD2UwcnvUgfuPx?= =?us-ascii?Q?5GfpmVH4Ksk4nZjHqMfa6uome1VFD2apDGdTVfMHnj9ZhGoiZwZWYsWdIOfu?= =?us-ascii?Q?naL+sFVX1tZlFPmWuTW8F20/+K+qMGz5iSbJ1na4TJHTGAo2cSkIo6KO1Ddf?= =?us-ascii?Q?/6VMHtiyilT8uoLZBiKEIR5z+/OIWHbMG65398AxG37L99Sspmwntj+tuAhd?= =?us-ascii?Q?r/6+E4Yw/QmNwlyWwQc3Je4xO36kZtpP6YGnnUXNC8U7PrzKhjP7U4EzhJuI?= =?us-ascii?Q?yxccZQT4BsaqrT6m/pSXEW8zYYz75CWGpl3COYoKSNXZuNxnLHgERQkmGulD?= =?us-ascii?Q?5T3zAlXVIr8eM96VgnwOx5BF8pued3Od0gWBBLYLz9aLJzqQT2e5tqKnrjrB?= =?us-ascii?Q?csnQFvntYcrjoUsUFo6ANGuO+sbQnDg/AgaIcsEwQxH9XoyskAD/wbM14D6v?= =?us-ascii?Q?/jFMPiKnAUj+SEejg98=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS0PR12MB6486.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?sq4XJrgYccefjG/pH1iEI7XOnk6gWkDmOku7x0FNid0r5T8RGwpKZllpQKQ3?= =?us-ascii?Q?EJngDTwSRW/e16IT1Dr2dzY7jgZNOgLelRHCbRdQeypMQ0uDxtv32O6/Dxmi?= =?us-ascii?Q?u5yTtiDn7D6ArjHeVYcNsWbpWq4xVqbph3jf4KnZYXq6eqpKlECe+IH0V4xq?= =?us-ascii?Q?keqlbeMDeUWwodmYL3P8qpexde3vG3s2Jbp2MusJA8XkQrTSdmA0W2szxDe1?= =?us-ascii?Q?KPKsTpDSIEi1FBvyYKLsQWnMzpUmzT3IrImhtnZU6Ostda/iaa6w+7Ok6gSa?= =?us-ascii?Q?Y3TWTkW5tAaWjsaZe9z8cyjYbVZrcNV1EFv/k33RD+LJsctcBnyZBlV0Bf9G?= =?us-ascii?Q?RdJVadNrGr1E/q83I8PKhEgO0jpg2V5j6w6eJZi3dTZfhwgRj7qyKZbncxkJ?= =?us-ascii?Q?D5giuPERYdvEatUdJ+7toagTOkVaoKBABsjBfre5bWxSHxe3FbSWcpPQNS80?= =?us-ascii?Q?00tD92KMLI1L1on7wkybESohfdddviRWrWsjgRYGvITrpp263KiVgXRujPus?= =?us-ascii?Q?/71gIaf2fMC9jjlK2h8blOLStbTobxvAaeWczI0V33hG5tKPlprdZRwFLdYh?= =?us-ascii?Q?vgT8DjhpeUiQ+/Q84vYuEEURs3quk2LnPyCURGI1wq5wNyeMMcxF88ALQ2uD?= =?us-ascii?Q?VfUf9NcyW3cCCLobIId6B0Lr4DjoQ04lhuZCbsUnMJ80zzxcLWCEzFiUXjAO?= =?us-ascii?Q?zYZydNud9LECw8wiuPARoGxd5ItfqcmTEHOc5N4PHATyEb7mC1AAw80y5N3z?= =?us-ascii?Q?YMsQ0Y+eydybfQRy/Q55tgST0+BZXCcseMJe9jPsR6plcweT3aNVQ8flqwLJ?= =?us-ascii?Q?zv+Ce4yy/Ne4jMaM08+UZYDOeW0I50chHW/s0EOiEVF8khv0BwHNOKkqY5nG?= =?us-ascii?Q?epVzdMH5rHUTPcpTIYvvN21PFaD+L4ZumNLGp80Q47sTl0ICb8qf2L4gAwVc?= =?us-ascii?Q?fRFz7UaUO3CAVBEudeVbrxVsl2HLLAinJ+v19+5wZ+toFzHk9jgsE0WC/cZS?= =?us-ascii?Q?1QoLLnjfrVARa08/WTP3FxhOnfKl2DzWF1D4X/J0/51vXLuM4PZrD0FJI7uS?= =?us-ascii?Q?0Jjxe5heDBCfyJ630QMiOJxWQLBCAwV6y41F5/XnRLTyhULYQvG1XjrlamV0?= =?us-ascii?Q?RDAWjrzW4mIGabJjGqxUBTOgi/dUeffMDvgpVUB4cp2Jzb+sQY904z2hbnAy?= =?us-ascii?Q?fe8m0jgxokLtzz2WVJPdgZQcFpDTvtT3+knE/qvi4jDepm3NZabgXFhO9jXY?= =?us-ascii?Q?d8jLbpBjdcEJpGhQx0p3MTEsA+K0sP9/ddO0ZwcZQSEV4N+6LYgYgyNvD0dR?= =?us-ascii?Q?igziLfRTpkawmMXJvYx7vGBN8uYiIon9+I84S8JYnIcwFYpEeLkK3KgI820d?= =?us-ascii?Q?e5Va3Oce240bVD1HLiGPPPr7QR7ac2qJWKHUM09dFINWOU6CxIyw+4dnw0In?= =?us-ascii?Q?sTBFnWzDC5XJso19iE0d8aAKoP6aOz+8y8bvrQYCJ1+Nj5t2yGd2qqnhVasZ?= =?us-ascii?Q?uxFdLnr/AQ9nsM2A+eLGZovl8z5kHpGXaXTf31zSKlNEyjMVbDeHwIr/gkA4?= =?us-ascii?Q?umn0eyTNsr8eR2Wv45+eM5iZ8uheaBj3vxeTLUrRtoSXEdewapqWiUjF95L/?= =?us-ascii?Q?aao97OZP3tkuSjGxmbiTzHtUSwPWcR9L4RIsiJfKS3OPst6MRAkcj5aTeKxY?= =?us-ascii?Q?KPSeB0BaK+4aku5AiTmKYPMBONng3xg/91Ms1YKus+khrmqIuFhBkKSbjaRu?= =?us-ascii?Q?kEQF2demKA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7dae80da-4bef-4fe4-4aa3-08de70b27ccc X-MS-Exchange-CrossTenant-AuthSource: DS0PR12MB6486.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Feb 2026 19:01:43.9519 (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: ppVZgDcNTgVxyFrfOrSimaMgbiBjxADA7zM2WkJIs5WYPoEhCUjVhffDSTih/0u7vSnLDk7zKubumzx/zZpRjg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB6629 On Fri, Feb 13, 2026 at 01:26:32AM +0000, Shinichiro Kawasaki wrote: > Cc+: Thomas, > > On Jan 30, 2026 / 20:16, Shin'ichiro Kawasaki wrote: > > On Jan 29, 2026 / 15:19, Paul E. McKenney wrote: > > [...] > > > And Thomas Gleixner posted an alleged fix to the CID issue here: > > > > > > https://lore.kernel.org/lkml/20260129210219.452851594@kernel.org/ > > > > > > Please let him know whether or not it helps. > > > > Good to see this fix candidate series, thanks :) I have set up the patches and > > started my regular test runs. So far, the hangs have been observed once or twice > > a week. To confirm the effect of the fix series, I think two weeks runs will be > > required. Once I get the result, will share it on this thread and with Thomas. > > Two weeks have passed, and I did not observed the hang! Then I'm confident that > the v1 fix series by Thomas avoided the rcu stall issue in my xfs-zoned test > systems. The series is already in v6.19 kernel tag as v2. Great. > > Thomas, just FYI. > > I faced mysterious kernel hangs during my regular fstests runs [1]. RCU experts > suggested the hangs might be caused by the recent MMCID changes. I tried your v1 > fix patch series "sched/mmcid: Cure mode transition woes", and confirmed it > avoids the hangs. Thank you for the fix. The v2 series is already in v6.19 > kernel tag, so this report might not be so valuable, but just in case. (And > thank you again for the additional quick fix for my blktests failure caused by > one of the patches in the series). > > [1] https://lore.kernel.org/rcu/aXdO52wh2rqTUi1E@shinmob/ Good to see that this got resolved. I am guessing there's nothing from an RCU point of view that could be done differently to diagnose this earlier, since I pretty quickly spotted it was MMCID related when I saw the existing report. Let me/us RCU folk know if there's anything else to do here though.. thanks, -- Joel Fernandes