From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (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 2E34A38422B for ; Wed, 4 Mar 2026 22:02:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=192.198.163.15 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772661779; cv=fail; b=NqkEW8fleG8jgB51btGk50SvYLPeSmXzapGi9kwg4xZa8fdWLhcqeuO3UwqMZaaDj/040No/TV8g4bU+l76Pk3Whmi9Ivmawycn67NSMVqX7P+fMFjXsFirLCQ43scmvrP4RdyhKc5CCmLXdeVxd9u0rsps0Pcx3En0aPzXLd18= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772661779; c=relaxed/simple; bh=Aifsn4HhFw1Z6/QaU4tZWLZVc12LFLDZCFBqo9LrLeA=; h=Date:From:To:CC:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=MMYDCgxTJS+2UgdoRSS6oSm/nTN+RVtQvTMowD6Qh2UO+PH8mY4rmG9CfFHpEP7lEw3D3JCuSFQ3oH+m049Z5fs+S5FQ26e51fVFEBGWJy2DFiU5kItadpZNHRzksy4f+awJsEyvf6C8j/PFXLELZb31agzhtM9te1lXF0FutQc= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ROoY1S7X; arc=fail smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ROoY1S7X" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1772661777; x=1804197777; h=date:from:to:cc:subject:message-id:references: content-transfer-encoding:in-reply-to:mime-version; bh=Aifsn4HhFw1Z6/QaU4tZWLZVc12LFLDZCFBqo9LrLeA=; b=ROoY1S7Xxt9e14KYERUqBnilRrRdKXu3eeLrzF8DnJ00yeAMx8tgtJP9 0q/qFjQ65x6WYfE8tMz9BMuonuJDkEYVb4DBsjGvHEtqc+CqXHS6HxvSX VAcnWZQEfalCUNqD56orvMbhzGn1cAqzUkztps8G3ga2JI1cZxNbxRXEN F4sSA5JMY/0uY8iXAEeb5soH88vU3HDk2FOvj6+muHc39sUspnvR3iKQf /CcCeIX6el0GjyIPKjDpsb5P/4sBC0fXDMJ6WFc2zm/qJGxsp5Ba/mfXB 7xeKugxI8iUbkmLtvmseWEnaGzFD7gY2AVcTQN+Gt87/lDmwDXGVon/2r A==; X-CSE-ConnectionGUID: 3iGGNs56TRqSPXtwquY2xw== X-CSE-MsgGUID: BpJzVa7EQmqgcLekbyunxg== X-IronPort-AV: E=McAfee;i="6800,10657,11719"; a="73859874" X-IronPort-AV: E=Sophos;i="6.21,324,1763452800"; d="scan'208";a="73859874" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Mar 2026 14:02:57 -0800 X-CSE-ConnectionGUID: wQinXnduTB6It1RpDEfpkg== X-CSE-MsgGUID: GnTFtDaqTQ+pMmEWubgRWQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,324,1763452800"; d="scan'208";a="241486058" Received: from fmsmsx903.amr.corp.intel.com ([10.18.126.92]) by fmviesa002.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Mar 2026 14:02:56 -0800 Received: from FMSMSX903.amr.corp.intel.com (10.18.126.92) by fmsmsx903.amr.corp.intel.com (10.18.126.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Wed, 4 Mar 2026 14:02:55 -0800 Received: from fmsedg903.ED.cps.intel.com (10.1.192.145) by FMSMSX903.amr.corp.intel.com (10.18.126.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37 via Frontend Transport; Wed, 4 Mar 2026 14:02:55 -0800 Received: from CY3PR05CU001.outbound.protection.outlook.com (40.93.201.45) by edgegateway.intel.com (192.55.55.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Wed, 4 Mar 2026 14:02:55 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=vxSveXm/rhlDn3BgzvP4Eu0hXI9QwW1nL6DwtRWdd8AaxqFo+ZRxbwZavXcTtLcGZkF+IH+8hdQFZF9ZBEx5BkhNDSL8bl4p7CxdLVqEllrntoCb6GdY7ictA1EHVE32oUrcQI3RbF3nMVHXkLQbYbc2e/Tz5e9gGI+cL4B8tQxXyrMxYfCdwPcLRRGviHWoIxqZBotvSupnJ9tv1HAmSY0PY9kfe966bsfvsW7o6qLKkRipDLQMq+uScH4wJkkkmqhpXy+IvxBfCBpgWpeIOkdj0FeY2KEceLe13bhLOuMTXeJ1A5pf5Ka2h40z/iqWuMhIXqKGrNWjFaoQoN3ssQ== 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=yi6h2BrRIDnX1vjDJK7HTd0HWwqigQ3mvutLLPGjrfI=; b=FvHj+PXRL6vzBOKoOykjIb1F4IXz8LhuRDQL2jHwe5kfSvX5EazmmuzSWLnbyaetPBCXwwIQWQCYAQ14ehhc7PalnUTUmbOq74sW96B9vktQEzJm3WjkFyLNeT2/OaS3YcfTXXjClYjDE+hEj8sQl2I+qwQqc0Ay6NBReJYY2djy0F7QQ+1kZhPvNdtuxQsuot0lEB+geBgvQp8+eRgfg2GJ0/WQp1SmMtTuNdl5UtWj7hJWW+lumnBYLQQQjuf/x+ZXUVqxwfB3PFG456zl0p+Z0Y2e+eHb3z3XmundpXBsjFBURs2MiCx+Yl0V5Fl21vHuiqS5Z4R+rLM/xhXSng== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from PH7PR11MB6522.namprd11.prod.outlook.com (2603:10b6:510:212::12) by IA1PR11MB6539.namprd11.prod.outlook.com (2603:10b6:208:3a1::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9678.17; Wed, 4 Mar 2026 22:02:48 +0000 Received: from PH7PR11MB6522.namprd11.prod.outlook.com ([fe80::e0c5:6cd8:6e67:dc0c]) by PH7PR11MB6522.namprd11.prod.outlook.com ([fe80::e0c5:6cd8:6e67:dc0c%4]) with mapi id 15.20.9654.022; Wed, 4 Mar 2026 22:02:47 +0000 Date: Wed, 4 Mar 2026 14:02:44 -0800 From: Matthew Brost To: Zi Yan CC: Balbir Singh , Usama Arif , Andrew Morton , , , , , , , , , , , , , , , , Usama Arif Subject: Re: [PATCH] mm/migrate_device: fix folio refcount leak on folio_split_unmapped failure Message-ID: References: <20260304120132.3973445-1-usamaarif642@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: BY3PR04CA0026.namprd04.prod.outlook.com (2603:10b6:a03:217::31) To PH7PR11MB6522.namprd11.prod.outlook.com (2603:10b6:510:212::12) 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: PH7PR11MB6522:EE_|IA1PR11MB6539:EE_ X-MS-Office365-Filtering-Correlation-Id: 73db87c1-9544-4507-138f-08de7a39c507 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: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH7PR11MB6522.namprd11.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: =?utf-8?B?TVBIdWlZaHg1K0FDRmJYSU45YlhOK05XaGpJd3h6RjM3NHp6aExoU2FMcW1j?= =?utf-8?B?bVZPZHM3Ny80VW5laVRwSVRBTW5TU3o2OStyVCtJQlkvYWdQMVRoeUZaNnV6?= =?utf-8?B?VEQ4V25vd0w2WFRRTGhMYmJrRFJiUi9BMDZlTU9QVkM0TmNpYkRack84bVdo?= =?utf-8?B?dW5DVEhLZVp1bzBFWE5uS0MzR1BXZWlSYllSWEdrcVN3Sm9BWmRQTGwyaWNR?= =?utf-8?B?UHc5aWlyT1M1LzFFazVnV2JxeUU1bEEzcUk4NUZlL0ttV01BV0tZMzFGNUJS?= =?utf-8?B?emhiYjVrVEY2ZGJ2Ly8rZ1hTMFdBMjgwM25jU0F4eDdFRDBEblgxT29vNWtk?= =?utf-8?B?dkMyZFZBSTQrOS9uaTg4aGlpam1Zd3dwaGg2VEEydGdIa3JGZU1UQ2VvTWVP?= =?utf-8?B?N3JxY0RiRktxNlNrR0gvY1VGQjFJTUQyZU5ML1BTSE0wbXhOV0NLeXNHa1dS?= =?utf-8?B?QnYvamt0aUI3aUZ4K2l6Q1ovT3JaUStWRTZ6elFyYkNCaU8zMzJTYS9HYzF6?= =?utf-8?B?bk9yalVnMVEvS2FSUDJpUm00RWxzUE5qMUhRQXF5endOaGZqZSt4dTBqWEFB?= =?utf-8?B?SisxeXBpQnh3Ylc2TThIc0RzQmMrWmcwak9Qbm1WN2hyQ0dQK1JxL25nU1Ja?= =?utf-8?B?MktMdC9KcmVIa05rMUNmeFUrWHhWdnM0alE1VFFuT3pCU0VVQkhlQmgzREoz?= =?utf-8?B?RHdQZUFQSFRsYmlZRkJWenhSQ213YlJydmFRTWZyUXdFSjkveml4eFRnYk1N?= =?utf-8?B?V3RSTFlOQ2xTU0NMSWZKMWZBNWFTclZMQ01nV1NJL0ZUdndTckRrY0JNN2V5?= =?utf-8?B?SUkvaGtDRUJlOWk3R1VXVDZTYWdnbmdSdHRWZ2NMdW85OWd1R3EvYzdyL0pF?= =?utf-8?B?Z0x0Sm1UaHk1RWRXY05EZEZGUzFmb2lhSDRUZHIvVElSZ2dnQ3lXSVMzOFY5?= =?utf-8?B?TWYyRWpqK2hDaEY4MUQ3ekRrUlNiWlI2N1k4OWxieGVPU0FjbWlKNnVSaUV4?= =?utf-8?B?OGo3N0FyVHJibXM0WEJOZHNEOE05dmQ5WUlYVnNoTDhxK3VWdlk4amYzV1VC?= =?utf-8?B?T1J5UXZkanZnc1d1c1E2NS9FTFpBTFdUY3hGNXJKc2FGTWJZRXRmQ2lxWDFR?= =?utf-8?B?VTBQaHpQTzZIaHQxT0ZuQjl1MVlzcHh5aGRwdlVCUnhMZTdSbGh3OERiRDhX?= =?utf-8?B?aFJUV2hneklUUjNCdDV1SkVobERHamltb0dDVWcrUXZzaEZCbm5NQU5jQjI0?= =?utf-8?B?N3A1dXJJaXE1M0tQNitPSXpDeE55R0NRQkhrSytjMk5xa2VhVGxNUUtTRDdC?= =?utf-8?B?aFdobHB0SjdEQUlZUzJ4NWhQM3k5L1ZWcEJQNkZDdTVBak9RcW9SVXpCVENi?= =?utf-8?B?dHFzNjI5ckJsbDE4WlpjZjlWd3FBV1BWVWZleXFKZyszRnRsY2RnOE1nQVQ4?= =?utf-8?B?MzRHZWRGYjJXaGFCcU5sQkZvcDIzd2M2U1hHMHRPQnA1WVIvYjlUWjhjdGM1?= =?utf-8?B?Y3dTeXpZOWpLdEpxQTE3SFVOOG5BVmVsOXM3KzVIdjZadzFHREkzVG8vYnhm?= =?utf-8?B?S2U3akZ5TEpicWVobEYwRzN6NGlGSys4SmxpaS8vc0ZsK1VzaThCdGpyVldE?= =?utf-8?B?WUl4dnZmUXp4Vkt6aGpSeWxxdXJDdHZ0dXRSSlovU0dmbmRCNmdyODhnTkJW?= =?utf-8?B?cnB4dUp5NExORHJvWms5OTcvQkgzSVNnM2V6MHhiVGxGK1ZhTjZGNEJtMC9Y?= =?utf-8?B?emJsVG94c3pKZGF0SEg5TzlUSDBVdkxWQWdTS2J1djZqeUZ5WEtrUGhnVWRV?= =?utf-8?B?RFVhVzM2Y0ZJNVJWREYwN3YwR3R3d3N0bjQvT0tuN3ZWS1V0OWFVbFdORW11?= =?utf-8?B?SmZVTEhUa0l3YU1xbWQ3N256dUdiSGFkd3R1QlZtSTdQZ1V6aXFHOVg2NU1l?= =?utf-8?B?eDFmSm1kcDM0bUl3R2VJaEZidDhWTjFidUQ3OVE4dGZmaUgydmNBVllFZlJE?= =?utf-8?B?L1dJNE5XS0dYSFpmR2xDbm84YjVKT1FKZTh5WkRDNUlKVm5zZkdBTCtkQ0ZZ?= =?utf-8?B?NkQ2S2NHWEdxbEhYSnRzbjV1TGdGM1lvOFp4Zldpek9lVHQ2NjlJMXNMZkJp?= =?utf-8?B?MXlYU24wb0dZZ1cyTDFPcmpGTngxSUNrWW11RHhoejgwb0ZwMXZpdld1L1NN?= =?utf-8?B?eHM0ZVdBZzdKNndwRTFSWnJUNy93cmpqekNFMkFuWGpYMXBZdXVJT1UwRnBX?= =?utf-8?B?SkU1RmQ3RTBpNVpLeUwzRXovRXFsbEFmTmR5KzlVVkU5SDNqTnc4anZwNm1X?= =?utf-8?B?VUw5YjJ6OFZIQzNyajBYclA2Qi9JVVNwWHRoK2F6SVM1bmtGMWF6bUw5alZ4?= =?utf-8?Q?i7yoU4cOmH6ZLnEI=3D?= X-Exchange-RoutingPolicyChecked: jGsKt+4vM8PbMoGr7jc4NctXjiuqoLCsqWd0jcJsab3FLkZB6G1cbZnspT4Hhomd8QAQ3BAusY5hD+gVekgISJDxxDMCPYrW6iZVaGGu2jmyoGahsNkAssmXCcNL5ikOuzcr+F29oNYiYkeyAnTf1PX4hAEkoqVx6NZIWxEL7Qta88D+5hmFkKxHPYvkyMt8miKvJ85dLYOWNWa7m8603loXCmT27CwUiVUxaDbrkRlvax+WE/7zX+zSEie3M4MzdjKNpP7pHzt8/B2zGtA7XtjLh2+/UnIIj4VeJJWKDC8FrD/LOby4LjCxMoxeEVbT8Z6I9N7JQbH4x+R1zCQIlQ== X-MS-Exchange-CrossTenant-Network-Message-Id: 73db87c1-9544-4507-138f-08de7a39c507 X-MS-Exchange-CrossTenant-AuthSource: PH7PR11MB6522.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Mar 2026 22:02:47.1801 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Zv3BKWKbMAWehTbwZLydsof7nPtw6ihwkkiQqV7/60Cu4HRIJtqc+suGJNoO2C31ll3EiykRGplCjkHGe+QyeA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR11MB6539 X-OriginatorOrg: intel.com On Wed, Mar 04, 2026 at 04:54:01PM -0500, Zi Yan wrote: > On 4 Mar 2026, at 16:48, Balbir Singh wrote: > > > On 3/5/26 02:17, Zi Yan wrote: > >> On 4 Mar 2026, at 7:01, Usama Arif wrote: > >> > >>> From: Usama Arif > >>> > >>> migrate_vma_split_unmapped_folio() takes an extra reference via > >>> folio_get() before calling folio_split_unmapped(). On success, the > >>> split consumes this reference: __folio_freeze_and_split_unmapped() > >>> expects the +1 in its folio_ref_freeze() check, and distributes it > >>> across the resulting sub-folios via folio_ref_unfreeze(...+1), which > >>> are later balanced by folio_put() calls in __migrate_device_finalize(). > >>> > >>> If folio_split_unmapped() fails (e.g., unexpected pinning returns > >>> -EAGAIN), the function returns without calling folio_put(). The extra > >>> reference is never released. > >>> > >>> Add the missing folio_put() on the error path. > >>> > >>> Fixes: 4265d67e405a4 ("mm/migrate_device: add THP splitting during migration") > >>> Closes: https://lore.kernel.org/all/CAA1CXcDyqPPwf_-W7B+PFQtL8HdoJGCEqVsVxq7DhOUB=L4PQA@mail.gmail.com/ > >>> Reported-by: Nico Pache > >>> Signed-off-by: Usama Arif > >>> --- > >>> mm/migrate_device.c | 4 +++- > >>> 1 file changed, 3 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/mm/migrate_device.c b/mm/migrate_device.c > >>> index 0a8b31939640f..351ecd9065d13 100644 > >>> --- a/mm/migrate_device.c > >>> +++ b/mm/migrate_device.c > >>> @@ -917,8 +917,10 @@ static int migrate_vma_split_unmapped_folio(struct migrate_vma *migrate, > >>> folio_get(folio); > >>> split_huge_pmd_address(migrate->vma, addr, true); > >>> ret = folio_split_unmapped(folio, 0); > >>> - if (ret) > >>> + if (ret) { > >>> + folio_put(folio); > >>> return ret; > >>> + } > >>> migrate->src[idx] &= ~MIGRATE_PFN_COMPOUND; > >>> flags = migrate->src[idx] & ((1UL << MIGRATE_PFN_SHIFT) - 1); > >>> pfn = migrate->src[idx] >> MIGRATE_PFN_SHIFT; > >>> -- > >>> 2.47.3 > >> > >> Add Balbir, who wrote the code, to comment on this. > >> > > > > Thanks Zi! > > > > Just wondering if there is a reproducer for the issue and how the fix was tested? > > I expect migrate_vma_finalize() to be called for folios, even when split failed and > > drop the lock. > > Does migrate_vma_finalize() do folio_put() for failed-to-split folios? > If so, how does it distinguish between split folios and failed-to-split folios? > By comparing source and destination folio orders? > > What we see from migrate_vma_split_unmapped_folio() is that > it adds a refcount for all input folios, but only drops a refcount > for the split folio. Isn’t it cause failed-to-split folios to have > additional refcount? I wonder if I’ve actually seen this bug. I’ve occasionally seen CPU page faults hang forever spinning, which could be caused by the page’s refcount accidentally being increased here. It’s quite difficult and random to reproduce, so I don’t have a real analysis of what’s happening in this case. Matt > > > Best Regards, > Yan, Zi