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dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.117.161 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.117.161; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.117.161) by CY4PEPF0000EE3B.mail.protection.outlook.com (10.167.242.14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9366.7 via Frontend Transport; Tue, 25 Nov 2025 17:14:50 +0000 Received: from rnnvmail201.nvidia.com (10.129.68.8) by mail.nvidia.com (10.129.200.67) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Tue, 25 Nov 2025 09:14:25 -0800 Received: from NV-2Y5XW94.nvidia.com (10.126.231.35) by rnnvmail201.nvidia.com (10.129.68.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Tue, 25 Nov 2025 09:14:22 -0800 From: Shameer Kolothum To: , CC: , , , , , , , Subject: [PATCH v3] mm/hugetlb: Fix incorrect error return from hugetlb_reserve_pages() Date: Tue, 25 Nov 2025 17:13:50 +0000 Message-ID: <20251125171350.86441-1-skolothumtho@nvidia.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: rnnvmail203.nvidia.com (10.129.68.9) To rnnvmail201.nvidia.com (10.129.68.8) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CY4PEPF0000EE3B:EE_|BY5PR12MB4082:EE_ X-MS-Office365-Filtering-Correlation-Id: a7556eaa-137b-4351-64d7-08de2c46245e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|82310400026|376014|1800799024; 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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Nov 2025 17:14:50.1764 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: a7556eaa-137b-4351-64d7-08de2c46245e X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CY4PEPF0000EE3B.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR12MB4082 Content-Type: text/plain; charset="utf-8" The function hugetlb_reserve_pages() returns the number of pages added to the reservation map on success and a negative error code on failure (e.g. -EINVAL, -ENOMEM). However, in some error paths, it may return -1 directly. For example, a failure at: if (hugetlb_acct_memory(h, gbl_reserve) < 0) goto out_put_pages; results in returning -1 (since add =3D -1), which may be misinterpreted in userspace as -EPERM. Fix this by explicitly capturing and propagating the return values from helper functions, and using -EINVAL for all other failure cases. Fixes: 986f5f2b4be3 ("mm/hugetlb: make hugetlb_reserve_pages() return nr of= entries updated") Reviewed-by: Joshua Hahn Reviewed-by: Jason Gunthorpe Signed-off-by: Shameer Kolothum Acked-by: Oscar Salvador --- From v2: https://lore.kernel.org/linux-mm/20251024094240.337630-1-skolothumtho@nvid= ia.com/ -Changed err return for resv_map_alloc() and region_add() failure cases. -Added R-by tags Thanks!=20 --- mm/hugetlb.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0455119716ec..868caa6476f5 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -7269,6 +7269,7 @@ long hugetlb_reserve_pages(struct inode *inode, struct resv_map *resv_map; struct hugetlb_cgroup *h_cg =3D NULL; long gbl_reserve, regions_needed =3D 0; + int err; =20 /* This should never happen */ if (from > to) { @@ -7308,8 +7309,10 @@ long hugetlb_reserve_pages(struct inode *inode, } else { /* Private mapping. */ resv_map =3D resv_map_alloc(); - if (!resv_map) + if (!resv_map) { + err =3D -ENOMEM; goto out_err; + } =20 chg =3D to - from; =20 @@ -7317,11 +7320,15 @@ long hugetlb_reserve_pages(struct inode *inode, set_vma_resv_flags(vma, HPAGE_RESV_OWNER); } =20 - if (chg < 0) + if (chg < 0) { + /* region_chg() above can return -ENOMEM */ + err =3D (chg =3D=3D -ENOMEM) ? -ENOMEM : -EINVAL; goto out_err; + } =20 - if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h), - chg * pages_per_huge_page(h), &h_cg) < 0) + err =3D hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h), + chg * pages_per_huge_page(h), &h_cg); + if (err < 0) goto out_err; =20 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) { @@ -7337,14 +7344,17 @@ long hugetlb_reserve_pages(struct inode *inode, * reservations already in place (gbl_reserve). */ gbl_reserve =3D hugepage_subpool_get_pages(spool, chg); - if (gbl_reserve < 0) + if (gbl_reserve < 0) { + err =3D gbl_reserve; goto out_uncharge_cgroup; + } =20 /* * Check enough hugepages are available for the reservation. * Hand the pages back to the subpool if there are not */ - if (hugetlb_acct_memory(h, gbl_reserve) < 0) + err =3D hugetlb_acct_memory(h, gbl_reserve); + if (err < 0) goto out_put_pages; =20 /* @@ -7363,6 +7373,7 @@ long hugetlb_reserve_pages(struct inode *inode, =20 if (unlikely(add < 0)) { hugetlb_acct_memory(h, -gbl_reserve); + err =3D add; goto out_put_pages; } else if (unlikely(chg > add)) { /* @@ -7423,7 +7434,7 @@ long hugetlb_reserve_pages(struct inode *inode, kref_put(&resv_map->refs, resv_map_release); set_vma_resv_map(vma, NULL); } - return chg < 0 ? chg : add < 0 ? add : -EINVAL; + return err; } =20 long hugetlb_unreserve_pages(struct inode *inode, long start, long end, --=20 2.43.0