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Tue, 6 Oct 2026 11:09:49 -0500 Message-ID: <023e73af-ebfd-4490-bf56-e91df10f7855@amd.com> Date: Tue, 6 Oct 2026 21:39:48 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/hugetlb: use kvmalloc_objs for hugetlb_fault_mutex_table To: , , , , , , CC: , References: <20261006160128.31447-1-dheerajkumar.srivastava@amd.com> Content-Language: en-US From: Dheeraj Kumar Srivastava In-Reply-To: <20261006160128.31447-1-dheerajkumar.srivastava@amd.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL6PEPF00022570:EE_|DS6PR12MB534567:EE_ X-MS-Office365-Filtering-Correlation-Id: c2577bc6-bc69-4c87-0d86-08df23c4426d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|23010399003|36860700016|1800799024|376014|10067099003|56012099006|18002099003|11063799006|22082099003; X-Microsoft-Antispam-Message-Info: knnqffqC+yVSbKMzx9fDDjGGjbFazaH0gRwd3Vv5/QXKwB5IjEXiqJWymrs2sjjQfEL88d6mIKLuOe6PqN3JuU2m6jrJ1bgsmJNmSysmTnRmfh8YFGrmgVpE7i2j1WD2RCBwDNYx6TDVXb2nXdAWCrQ3ocMrUpTXBDoZ+eP55nynDuoFrSI4IcPEwyKxcyvoW3Tg8BMLxmtKt9f+WM8ZThiBY4nRgZ2WgiQ33Ndwsge5LEqh6qAuSpzG3jKUiaKFpewG4QBualsfN3QufiOluHLOmbicU2e+3Jpr1Eicxq4jOsybg+o9u/2A5d5KfJMz9YnrmwKCl5gGQ0ReP2OG2+eKEmoF+S/KmDPOwjFQd8B9vpSeJ3cHD4/JWAkUC6Esxtg7HVU6Mi3KcwriTIk0cVBpUI+MpSc+4VtDTP1sKOt8cCAW19DaCuEbctmLEH5aMkJRlqwy+wWtSQhUMy3pmUr51Aa99kYNb6ZEpmeU7vxbIZhNAxLuKD3IIqWae1ZJt5M/Al4ZpXvLFt4lPhFprumCuLEIuCOo5ruFwczb9lIrgEqrP5ffXa72dPIqATW/Sfogs2JLaliOP9t1SqHeol+2g4+vv1zM4WyUAbQ7Sey4vrojJ5MBTziXXxXXHT6mrXvNaFO2JfaveEkOT7mGBusnOx4o0qrBuzG52SwV0pB0VkkiN1wBQkC6aX+FJjt0 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb08.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(23010399003)(36860700016)(1800799024)(376014)(10067099003)(56012099006)(18002099003)(11063799006)(22082099003);DIR:OUT;SFP:1101; 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The subsequent kmalloc for the mutex table can exceed > MAX_PAGE_ORDER when struct mutex is enlarged by debug options like > CONFIG_DEBUG_MUTEXES and CONFIG_DEBUG_LOCK_ALLOC, resulting in: > > WARNING: at __alloc_frozen_pages_noprof (order > MAX_PAGE_ORDER) > kernel BUG at mm/hugetlb.c (BUG_ON(!hugetlb_fault_mutex_table)) > Kernel panic - not syncing: Fatal exception > > Switch to kvmalloc_objs() so the allocation falls back to vmalloc when > the contiguous physical allocation is too large. The table is only > accessed by index, so virtual contiguity is sufficient. Sorry, I forgot to include the "Changes since v1" change log. Changes since v1: -> Use kvmalloc_objs() instead of kvmalloc_array(). Thanks Dheeraj > > Fixes: 8382d914ebf7 ("mm, hugetlb: improve page-fault scalability") > Signed-off-by: Dheeraj Kumar Srivastava > --- > mm/hugetlb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index cea25773a6c9..6fc5c0bdb500 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -4177,7 +4177,7 @@ static int __init hugetlb_init(void) > num_fault_mutexes = 1; > #endif > hugetlb_fault_mutex_table = > - kmalloc_objs(struct mutex, num_fault_mutexes); > + kvmalloc_objs(struct mutex, num_fault_mutexes); > BUG_ON(!hugetlb_fault_mutex_table); > > for (i = 0; i < num_fault_mutexes; i++)