From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F3EBC433FE for ; Thu, 10 Nov 2022 09:09:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229702AbiKJJI7 (ORCPT ); Thu, 10 Nov 2022 04:08:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229700AbiKJJI5 (ORCPT ); Thu, 10 Nov 2022 04:08:57 -0500 Received: from NAM11-CO1-obe.outbound.protection.outlook.com (mail-co1nam11on2088.outbound.protection.outlook.com [40.107.220.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C960C659D for ; Thu, 10 Nov 2022 01:08:55 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=SdVxcm0AvjtsM+oqDSlxs0XFp2fTW8lt8+Uiyq+TEiIJ0arbs0ypbDyEq6wyoh4aplVoW0ZmnfHSQQ4Gkwj5ZMAWy3McpWAX8H5MCq6umdhE6PnYO3O/YF6H3meFDzT9FAJbZAgLCfhFAtUKdgofv12uV1rpTcFGY6CTemYXNtljXoXKE9s+3E4OebOtrbJ3qhUN/8lYYxKoCPk5R6GAf+ioTa8Y8x5fQMCShZyznjw1ssIviA/KASet+5TneJh4MBcNMPbqgXLd5RV+L5SLkiQzZFzI2tKpaNL6L0MnUDZzb9DDK14D0BTpiwcNb6+d/5HaR7rpfzNrx/hrJe9oXg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=J/+biABVqal2H4180pM3lIQR+G/s86S3C93qa1zdVSY=; b=KMWmTZ+2afreImAnI2EOH5wvI3veMhEejFVbM/4QrcOu/Qn8SiILYLq3bP0FA/buxnTpMuxDOj08ds0j+FFumTfIzIx1cgQjNOuf4iYeCRX3c3g2UCHbImKrO0kw6SPDqeZYMgTGho+nlGc5LkQFL/QVYISZWlgA2kxUT2LAyEsf/ORBe9IDs35puZEP7PKwDfNA0gBxeTH74j94NAVwGu1OC5r1629hQ/GwLxPeMiO38X1jYOhKcc3zeWQWKBeRMzr/UOxE5QE5XkYbqvRE2G7yH+twnfgLfWvT4OmDNrOsN2PYki5uzdoS50y4jtyLVgzTTwSq3XhXX4eBFuhO2Q== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=J/+biABVqal2H4180pM3lIQR+G/s86S3C93qa1zdVSY=; b=mrerCIRfBqPxD7UVBOHzJ+/liXweyx1LKJw88UlO2eIrvPiEUZMDOCEgg0bDVNz/iDKaOFBEVzrwis20b6iQ9oSKB/YkN4rQ9rdz5JKArSZnO0uCKxDCE7qOjRLmg8FYJkZs/8Obp2P9FXC4aWIIqWndm4OKJQLGi7J53Y6mlQ1jrPZqGm3DCp8oAtrNn4zax/sLm6SWJEcltisjiVHFUrLhU9XPl1lNrRn1p8S/7JBamoYvyfGsbKK4veb8qpKGpxffgYDK68QFpiEVlJEf3cfQ3dJOA6gBhcUutjY9xVC45ZLQzauaurLYvCPcq0lAzkvTFZINSqyhtOxyYKQlqw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS7PR12MB6288.namprd12.prod.outlook.com (2603:10b6:8:93::7) by MW4PR12MB6707.namprd12.prod.outlook.com (2603:10b6:303:1ee::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5791.25; Thu, 10 Nov 2022 09:08:54 +0000 Received: from DS7PR12MB6288.namprd12.prod.outlook.com ([fe80::fe97:fe7a:9ed0:137c]) by DS7PR12MB6288.namprd12.prod.outlook.com ([fe80::fe97:fe7a:9ed0:137c%3]) with mapi id 15.20.5791.025; Thu, 10 Nov 2022 09:08:54 +0000 Message-ID: <15d10423-9f8b-668a-ba14-f9c15a3b3782@nvidia.com> Date: Thu, 10 Nov 2022 11:08:43 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH net] net: sched: fix race condition in qdisc_graft() Content-Language: en-US From: Gal Pressman To: Eric Dumazet , Maxim Mikityanskiy Cc: Jakub Kicinski , Maxim Mikityanskiy , "David S . Miller" , Paolo Abeni , netdev@vger.kernel.org, Cong Wang , eric.dumazet@gmail.com, syzbot , Dmitry Vyukov , Tariq Toukan References: <20221018203258.2793282-1-edumazet@google.com> <162f9155-dfe3-9d78-c59f-f47f7dcf83f5@nvidia.com> <20221103082751.353faa4d@kernel.org> <46dde206-53bf-8ba8-f964-6bcc22a303c7@nvidia.com> In-Reply-To: <46dde206-53bf-8ba8-f964-6bcc22a303c7@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: LO4P123CA0640.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:296::21) To DS7PR12MB6288.namprd12.prod.outlook.com (2603:10b6:8:93::7) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB6288:EE_|MW4PR12MB6707:EE_ X-MS-Office365-Filtering-Correlation-Id: ef06a0f8-56f3-4ac7-4cf7-08dac2fb30e0 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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:DS7PR12MB6288.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(39860400002)(376002)(366004)(346002)(136003)(396003)(451199015)(966005)(2906002)(6666004)(186003)(66476007)(478600001)(6486002)(38100700002)(2616005)(36756003)(54906003)(26005)(53546011)(6506007)(316002)(110136005)(6512007)(31696002)(83380400001)(66946007)(66556008)(107886003)(86362001)(8676002)(4326008)(31686004)(41300700001)(8936002)(7416002)(5660300002)(30864003)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?R21sRHRpVG55VmJvazRwcW8rS3VwRmFaenJSV1JCakZuODlBUnFSQU5iRDI1?= =?utf-8?B?U2l2MjIycE0xU0drQVNRSWIwdHFWb0xtUkhtbVBBY3JiY2JZSGxmTkE3M1Y3?= =?utf-8?B?RHdESzNmSlA1dElTczdaYjJVMzlFSmkwbURxOUh1ZlBBb3hmQVlzcWpvN09n?= =?utf-8?B?aEJ3Q1dLcDEzSkx4Mm1acXFkS2NGL2x6SGtYODRQS3p1akptanE5ZGh0bi80?= =?utf-8?B?OGJqWTg0ZzQyYy9DdkFlZG1hRkZkU0tSTS9abEREbVVHS1hVenBlK3B0VGpT?= =?utf-8?B?OC9RMU5NYlE3RjlUMmlaeFR5dE1NeC9Ra01DZ1NMZ3EvR1BQN0NyMkN4N0dN?= =?utf-8?B?NWxUMEYwcThPZ1J6NXZPR0NQT1AxZ3Z4ZmtNY0RsWE1wcDZ4NWpMYWpsMDBp?= =?utf-8?B?eFJWSitaVXc0VzNVYVpaYko4QlIxQ0hUTG9sOFJGZ1pBNmNLNEMzcWxVOC9u?= =?utf-8?B?djkrZ0VVSzEwc3pCTlp5UldWcy80MWNXV3VOLzlnclE5NU44UmxEL25qbkc4?= =?utf-8?B?NTJHclhwZlpqazJYdkFDRlBsWXRkT3pwanRUZGVRbFZJdXIrUFByK01mVWlD?= =?utf-8?B?a3hOc0ZaMTRKSFJZL2duZi9Ka3VMVURvUGkwNm9DeUF4ZHRoZE5SSkRuMzNS?= =?utf-8?B?YWVjbm9wL2xTdU00MDRnTkQwM09jMnoyc3ZaanpPSnNlZ25aL3lUT3R5MHp6?= =?utf-8?B?enJoQ2VyaWlOK011V0JJN0kzOWpHek40UnhCZEloYTJsSWZoOFhHVkI2MXFi?= =?utf-8?B?a2lkdklxN3o2bjNudWY5UkEzZDZHRnZmODRxMXdTbXF6ZDVnbGFGTDZOZTV2?= =?utf-8?B?ZlpRbzJwaVJKcmJFUHZqTDZvQnF0M2lxQkZXSE5UUzRTK3Q5dnNrV1VvSmZv?= =?utf-8?B?RDcwMGxhamJFT1FVaHIyVHhBbVUvcVpvQzluUUJYWW9aNXF5dmdTUEI0eVF4?= =?utf-8?B?L25XOFBETEVtdCtjYlUrWkNJN002OVdmRnQ2cURYWkRpdmNUaUhXNTVYN3ZC?= =?utf-8?B?Rml3d0lSa1JVQmpYVkwvM0l1UWhQL2VDSU1FNUFVMjlWeXBYa2hQeCtmYTlM?= =?utf-8?B?YXhweWlrNEtRWWpjcUxRSW9Ieml6bk04cXN4NVJEdGgybFdRWURxeE1vSUlU?= =?utf-8?B?a0FsNXRoZkNTeTBhUEJVUGpITEx2NGpxOWphZnVrdE1ibHU5aHBhd1dINXJP?= =?utf-8?B?MXlVWnlHWjg0aWRDRFhuV1NwLzc0UFZvMWhrdWl1bjNaRnk1dFFVTDFlMk9V?= =?utf-8?B?QjhVUFNIeHNXTm5kbkJGcnVkMytFK2xnZFJDUHpQbkNQYll3RktYWXZybnc2?= =?utf-8?B?eGYwYkN0T1BCcmhHb002V0pZdnM3RW1MU3c3OEVBOWVzWlkzRkhCNWw2cFR3?= =?utf-8?B?V1g5MHBaVk9ORy92MlR6N0ZvN2xzeGdxK0FKc1JuTzZBUnphdFV3MXplM3dW?= =?utf-8?B?a3FydUNLeC9CQmNvVWlzTnNjTzJXS1dGR0tBUEs3RkgydVBaSHE5Rk5hVmlC?= =?utf-8?B?RjNVRFlvd0ZhdUdWVFZmenZpOUxIamhiVll5eUx2d3RWZ1ZYZlRQTjM4ZU1z?= =?utf-8?B?YjZQQVdmWCtXU29qMUxEVHYxRnNyNEhCMGJqS0I4SDJVbzd0ZUc3MHQ4cW9O?= =?utf-8?B?Zjh6ZDl6QXNPS3FkbVIvdXY0Q01RdWs2cGlha3BYN0VqcXNFS21iN3k3WVJN?= =?utf-8?B?ZlJobUhKY1ZRNVJIWlBvczVKUHEwOWRJWXlOVzNhN2x6T1Q0RHVuN0lyMHpU?= =?utf-8?B?UkFLb1Y5V3NPSy92bXFzYnp3MHJBSEJLY0FraUFjTVk1d2hBTitaUWJNZlBJ?= =?utf-8?B?SHZ1VC9LQk8wK3lMbXBXZTZ3R2hOemRUbEZOdGl2cEpVVjlRcFpqbzZ4SG9h?= =?utf-8?B?aEhMcjl0MTNUNEhJTktiWXpQOGpJVU9GOENYckVNVnJWaG4rTkFVWWdwQ3V4?= =?utf-8?B?d0w0M3BRZnBSaG5KSDRjcDBTZ2FrOEJjNjJubE0rU0UxekJ1NmRlRzB3aGJs?= =?utf-8?B?S0k3VUZKMWNVMVh5YzhCTUZTQm9Xam51bFNlTEdpaGVSb3FuWFFpVlJweHJV?= =?utf-8?B?MzdHcFFuV1BZd2ZKRnFZelV1MkxMb29KRm1KRWo2cDdZYlFjRmtCOEpUcDhF?= =?utf-8?Q?1gqwIeEIcciQ4v2K/KgwKa9ju?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: ef06a0f8-56f3-4ac7-4cf7-08dac2fb30e0 X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB6288.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Nov 2022 09:08:54.1275 (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: qzmTuCCsxTGw2LQg89M3S1adVFzLj3gSwDZjjTrrF2pPQJpylFuHJc/CfWG6TeCj X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB6707 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 06/11/2022 10:07, Gal Pressman wrote: > On 03/11/2022 18:33, Eric Dumazet wrote: >> On Thu, Nov 3, 2022 at 9:31 AM Maxim Mikityanskiy wrote: >>> On Thu, 3 Nov 2022 at 17:30, Eric Dumazet wrote: >>>> On Thu, Nov 3, 2022 at 8:27 AM Jakub Kicinski wrote: >>>>> On Thu, 3 Nov 2022 08:17:06 -0700 Eric Dumazet wrote: >>>>>> On Thu, Nov 3, 2022 at 6:34 AM Gal Pressman wrote: >>>>>>> On 18/10/2022 23:32, Eric Dumazet wrote: >>>>>>>> We had one syzbot report [1] in syzbot queue for a while. >>>>>>>> I was waiting for more occurrences and/or a repro but >>>>>>>> Dmitry Vyukov spotted the issue right away. >>>>>>>> >>>>>>>> >>>>>>>> qdisc_graft() drops reference to qdisc in notify_and_destroy >>>>>>>> while it's still assigned to dev->qdisc >>>>>>>> >>>>>>>> >>>>>>>> Indeed, RCU rules are clear when replacing a data structure. >>>>>>>> The visible pointer (dev->qdisc in this case) must be updated >>>>>>>> to the new object _before_ RCU grace period is started >>>>>>>> (qdisc_put(old) in this case). >>>>>>>> >>>>>>>> [1] >>>>>>>> BUG: KASAN: use-after-free in __tcf_qdisc_find.part.0+0xa3a/0xac0 net/sched/cls_api.c:1066 >>>>>>>> Read of size 4 at addr ffff88802065e038 by task syz-executor.4/21027 >>>>>>>> >>>>>>>> CPU: 0 PID: 21027 Comm: syz-executor.4 Not tainted 6.0.0-rc3-syzkaller-00363-g7726d4c3e60b #0 >>>>>>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 >>>>>>>> Call Trace: >>>>>>>> >>>>>>>> __dump_stack lib/dump_stack.c:88 [inline] >>>>>>>> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 >>>>>>>> print_address_description mm/kasan/report.c:317 [inline] >>>>>>>> print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 >>>>>>>> kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 >>>>>>>> __tcf_qdisc_find.part.0+0xa3a/0xac0 net/sched/cls_api.c:1066 >>>>>>>> __tcf_qdisc_find net/sched/cls_api.c:1051 [inline] >>>>>>>> tc_new_tfilter+0x34f/0x2200 net/sched/cls_api.c:2018 >>>>>>>> rtnetlink_rcv_msg+0x955/0xca0 net/core/rtnetlink.c:6081 >>>>>>>> netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501 >>>>>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] >>>>>>>> netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345 >>>>>>>> netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921 >>>>>>>> sock_sendmsg_nosec net/socket.c:714 [inline] >>>>>>>> sock_sendmsg+0xcf/0x120 net/socket.c:734 >>>>>>>> ____sys_sendmsg+0x6eb/0x810 net/socket.c:2482 >>>>>>>> ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536 >>>>>>>> __sys_sendmsg+0xf3/0x1c0 net/socket.c:2565 >>>>>>>> do_syscall_x64 arch/x86/entry/common.c:50 [inline] >>>>>>>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 >>>>>>>> entry_SYSCALL_64_after_hwframe+0x63/0xcd >>>>>>>> RIP: 0033:0x7f5efaa89279 >>>>>>>> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 >>>>>>>> RSP: 002b:00007f5efbc31168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e >>>>>>>> RAX: ffffffffffffffda RBX: 00007f5efab9bf80 RCX: 00007f5efaa89279 >>>>>>>> RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005 >>>>>>>> RBP: 00007f5efaae32e9 R08: 0000000000000000 R09: 0000000000000000 >>>>>>>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 >>>>>>>> R13: 00007f5efb0cfb1f R14: 00007f5efbc31300 R15: 0000000000022000 >>>>>>>> >>>>>>>> >>>>>>>> Allocated by task 21027: >>>>>>>> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 >>>>>>>> kasan_set_track mm/kasan/common.c:45 [inline] >>>>>>>> set_alloc_info mm/kasan/common.c:437 [inline] >>>>>>>> ____kasan_kmalloc mm/kasan/common.c:516 [inline] >>>>>>>> ____kasan_kmalloc mm/kasan/common.c:475 [inline] >>>>>>>> __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525 >>>>>>>> kmalloc_node include/linux/slab.h:623 [inline] >>>>>>>> kzalloc_node include/linux/slab.h:744 [inline] >>>>>>>> qdisc_alloc+0xb0/0xc50 net/sched/sch_generic.c:938 >>>>>>>> qdisc_create_dflt+0x71/0x4a0 net/sched/sch_generic.c:997 >>>>>>>> attach_one_default_qdisc net/sched/sch_generic.c:1152 [inline] >>>>>>>> netdev_for_each_tx_queue include/linux/netdevice.h:2437 [inline] >>>>>>>> attach_default_qdiscs net/sched/sch_generic.c:1170 [inline] >>>>>>>> dev_activate+0x760/0xcd0 net/sched/sch_generic.c:1229 >>>>>>>> __dev_open+0x393/0x4d0 net/core/dev.c:1441 >>>>>>>> __dev_change_flags+0x583/0x750 net/core/dev.c:8556 >>>>>>>> rtnl_configure_link+0xee/0x240 net/core/rtnetlink.c:3189 >>>>>>>> rtnl_newlink_create net/core/rtnetlink.c:3371 [inline] >>>>>>>> __rtnl_newlink+0x10b8/0x17e0 net/core/rtnetlink.c:3580 >>>>>>>> rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3593 >>>>>>>> rtnetlink_rcv_msg+0x43a/0xca0 net/core/rtnetlink.c:6090 >>>>>>>> netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501 >>>>>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] >>>>>>>> netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345 >>>>>>>> netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921 >>>>>>>> sock_sendmsg_nosec net/socket.c:714 [inline] >>>>>>>> sock_sendmsg+0xcf/0x120 net/socket.c:734 >>>>>>>> ____sys_sendmsg+0x6eb/0x810 net/socket.c:2482 >>>>>>>> ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536 >>>>>>>> __sys_sendmsg+0xf3/0x1c0 net/socket.c:2565 >>>>>>>> do_syscall_x64 arch/x86/entry/common.c:50 [inline] >>>>>>>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 >>>>>>>> entry_SYSCALL_64_after_hwframe+0x63/0xcd >>>>>>>> >>>>>>>> Freed by task 21020: >>>>>>>> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 >>>>>>>> kasan_set_track+0x21/0x30 mm/kasan/common.c:45 >>>>>>>> kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 >>>>>>>> ____kasan_slab_free mm/kasan/common.c:367 [inline] >>>>>>>> ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:329 >>>>>>>> kasan_slab_free include/linux/kasan.h:200 [inline] >>>>>>>> slab_free_hook mm/slub.c:1754 [inline] >>>>>>>> slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780 >>>>>>>> slab_free mm/slub.c:3534 [inline] >>>>>>>> kfree+0xe2/0x580 mm/slub.c:4562 >>>>>>>> rcu_do_batch kernel/rcu/tree.c:2245 [inline] >>>>>>>> rcu_core+0x7b5/0x1890 kernel/rcu/tree.c:2505 >>>>>>>> __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571 >>>>>>>> >>>>>>>> Last potentially related work creation: >>>>>>>> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 >>>>>>>> __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348 >>>>>>>> call_rcu+0x99/0x790 kernel/rcu/tree.c:2793 >>>>>>>> qdisc_put+0xcd/0xe0 net/sched/sch_generic.c:1083 >>>>>>>> notify_and_destroy net/sched/sch_api.c:1012 [inline] >>>>>>>> qdisc_graft+0xeb1/0x1270 net/sched/sch_api.c:1084 >>>>>>>> tc_modify_qdisc+0xbb7/0x1a00 net/sched/sch_api.c:1671 >>>>>>>> rtnetlink_rcv_msg+0x43a/0xca0 net/core/rtnetlink.c:6090 >>>>>>>> netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501 >>>>>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] >>>>>>>> netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345 >>>>>>>> netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921 >>>>>>>> sock_sendmsg_nosec net/socket.c:714 [inline] >>>>>>>> sock_sendmsg+0xcf/0x120 net/socket.c:734 >>>>>>>> ____sys_sendmsg+0x6eb/0x810 net/socket.c:2482 >>>>>>>> ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536 >>>>>>>> __sys_sendmsg+0xf3/0x1c0 net/socket.c:2565 >>>>>>>> do_syscall_x64 arch/x86/entry/common.c:50 [inline] >>>>>>>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 >>>>>>>> entry_SYSCALL_64_after_hwframe+0x63/0xcd >>>>>>>> >>>>>>>> Second to last potentially related work creation: >>>>>>>> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 >>>>>>>> __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348 >>>>>>>> kvfree_call_rcu+0x74/0x940 kernel/rcu/tree.c:3322 >>>>>>>> neigh_destroy+0x431/0x630 net/core/neighbour.c:912 >>>>>>>> neigh_release include/net/neighbour.h:454 [inline] >>>>>>>> neigh_cleanup_and_release+0x1f8/0x330 net/core/neighbour.c:103 >>>>>>>> neigh_del net/core/neighbour.c:225 [inline] >>>>>>>> neigh_remove_one+0x37d/0x460 net/core/neighbour.c:246 >>>>>>>> neigh_forced_gc net/core/neighbour.c:276 [inline] >>>>>>>> neigh_alloc net/core/neighbour.c:447 [inline] >>>>>>>> ___neigh_create+0x18b5/0x29a0 net/core/neighbour.c:642 >>>>>>>> ip6_finish_output2+0xfb8/0x1520 net/ipv6/ip6_output.c:125 >>>>>>>> __ip6_finish_output net/ipv6/ip6_output.c:195 [inline] >>>>>>>> ip6_finish_output+0x690/0x1160 net/ipv6/ip6_output.c:206 >>>>>>>> NF_HOOK_COND include/linux/netfilter.h:296 [inline] >>>>>>>> ip6_output+0x1ed/0x540 net/ipv6/ip6_output.c:227 >>>>>>>> dst_output include/net/dst.h:451 [inline] >>>>>>>> NF_HOOK include/linux/netfilter.h:307 [inline] >>>>>>>> NF_HOOK include/linux/netfilter.h:301 [inline] >>>>>>>> mld_sendpack+0xa09/0xe70 net/ipv6/mcast.c:1820 >>>>>>>> mld_send_cr net/ipv6/mcast.c:2121 [inline] >>>>>>>> mld_ifc_work+0x71c/0xdc0 net/ipv6/mcast.c:2653 >>>>>>>> process_one_work+0x991/0x1610 kernel/workqueue.c:2289 >>>>>>>> worker_thread+0x665/0x1080 kernel/workqueue.c:2436 >>>>>>>> kthread+0x2e4/0x3a0 kernel/kthread.c:376 >>>>>>>> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 >>>>>>>> >>>>>>>> The buggy address belongs to the object at ffff88802065e000 >>>>>>>> which belongs to the cache kmalloc-1k of size 1024 >>>>>>>> The buggy address is located 56 bytes inside of >>>>>>>> 1024-byte region [ffff88802065e000, ffff88802065e400) >>>>>>>> >>>>>>>> The buggy address belongs to the physical page: >>>>>>>> page:ffffea0000819600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20658 >>>>>>>> head:ffffea0000819600 order:3 compound_mapcount:0 compound_pincount:0 >>>>>>>> flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) >>>>>>>> raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888011841dc0 >>>>>>>> raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 >>>>>>>> page dumped because: kasan: bad access detected >>>>>>>> page_owner tracks the page as allocated >>>>>>>> page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3523, tgid 3523 (sshd), ts 41495190986, free_ts 41417713212 >>>>>>>> prep_new_page mm/page_alloc.c:2532 [inline] >>>>>>>> get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283 >>>>>>>> __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5515 >>>>>>>> alloc_pages+0x1a6/0x270 mm/mempolicy.c:2270 >>>>>>>> alloc_slab_page mm/slub.c:1824 [inline] >>>>>>>> allocate_slab+0x27e/0x3d0 mm/slub.c:1969 >>>>>>>> new_slab mm/slub.c:2029 [inline] >>>>>>>> ___slab_alloc+0x7f1/0xe10 mm/slub.c:3031 >>>>>>>> __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118 >>>>>>>> slab_alloc_node mm/slub.c:3209 [inline] >>>>>>>> __kmalloc_node_track_caller+0x2f2/0x380 mm/slub.c:4955 >>>>>>>> kmalloc_reserve net/core/skbuff.c:358 [inline] >>>>>>>> __alloc_skb+0xd9/0x2f0 net/core/skbuff.c:430 >>>>>>>> alloc_skb_fclone include/linux/skbuff.h:1307 [inline] >>>>>>>> tcp_stream_alloc_skb+0x38/0x580 net/ipv4/tcp.c:861 >>>>>>>> tcp_sendmsg_locked+0xc36/0x2f80 net/ipv4/tcp.c:1325 >>>>>>>> tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1483 >>>>>>>> inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819 >>>>>>>> sock_sendmsg_nosec net/socket.c:714 [inline] >>>>>>>> sock_sendmsg+0xcf/0x120 net/socket.c:734 >>>>>>>> sock_write_iter+0x291/0x3d0 net/socket.c:1108 >>>>>>>> call_write_iter include/linux/fs.h:2187 [inline] >>>>>>>> new_sync_write fs/read_write.c:491 [inline] >>>>>>>> vfs_write+0x9e9/0xdd0 fs/read_write.c:578 >>>>>>>> ksys_write+0x1e8/0x250 fs/read_write.c:631 >>>>>>>> page last free stack trace: >>>>>>>> reset_page_owner include/linux/page_owner.h:24 [inline] >>>>>>>> free_pages_prepare mm/page_alloc.c:1449 [inline] >>>>>>>> free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1499 >>>>>>>> free_unref_page_prepare mm/page_alloc.c:3380 [inline] >>>>>>>> free_unref_page+0x19/0x4d0 mm/page_alloc.c:3476 >>>>>>>> __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2548 >>>>>>>> qlink_free mm/kasan/quarantine.c:168 [inline] >>>>>>>> qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 >>>>>>>> kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294 >>>>>>>> __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:447 >>>>>>>> kasan_slab_alloc include/linux/kasan.h:224 [inline] >>>>>>>> slab_post_alloc_hook mm/slab.h:727 [inline] >>>>>>>> slab_alloc_node mm/slub.c:3243 [inline] >>>>>>>> slab_alloc mm/slub.c:3251 [inline] >>>>>>>> __kmem_cache_alloc_lru mm/slub.c:3258 [inline] >>>>>>>> kmem_cache_alloc+0x267/0x3b0 mm/slub.c:3268 >>>>>>>> kmem_cache_zalloc include/linux/slab.h:723 [inline] >>>>>>>> alloc_buffer_head+0x20/0x140 fs/buffer.c:2974 >>>>>>>> alloc_page_buffers+0x280/0x790 fs/buffer.c:829 >>>>>>>> create_empty_buffers+0x2c/0xee0 fs/buffer.c:1558 >>>>>>>> ext4_block_write_begin+0x1004/0x1530 fs/ext4/inode.c:1074 >>>>>>>> ext4_da_write_begin+0x422/0xae0 fs/ext4/inode.c:2996 >>>>>>>> generic_perform_write+0x246/0x560 mm/filemap.c:3738 >>>>>>>> ext4_buffered_write_iter+0x15b/0x460 fs/ext4/file.c:270 >>>>>>>> ext4_file_write_iter+0x44a/0x1660 fs/ext4/file.c:679 >>>>>>>> call_write_iter include/linux/fs.h:2187 [inline] >>>>>>>> new_sync_write fs/read_write.c:491 [inline] >>>>>>>> vfs_write+0x9e9/0xdd0 fs/read_write.c:578 >>>>>>>> >>>>>>>> Fixes: af356afa010f ("net_sched: reintroduce dev->qdisc for use by sch_api") >>>>>>>> Reported-by: syzbot >>>>>>>> Diagnosed-by: Dmitry Vyukov >>>>>>>> Signed-off-by: Eric Dumazet >>>>>>>> --- >>>>>>>> net/sched/sch_api.c | 5 +++-- >>>>>>>> 1 file changed, 3 insertions(+), 2 deletions(-) >>>>>>>> >>>>>>>> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c >>>>>>>> index c98af0ada706efee202a20a6bfb6f2b984106f45..4a27dfb1ba0faab3692a82969fb8b78768742779 100644 >>>>>>>> --- a/net/sched/sch_api.c >>>>>>>> +++ b/net/sched/sch_api.c >>>>>>>> @@ -1099,12 +1099,13 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent, >>>>>>>> >>>>>>>> skip: >>>>>>>> if (!ingress) { >>>>>>>> - notify_and_destroy(net, skb, n, classid, >>>>>>>> - rtnl_dereference(dev->qdisc), new); >>>>>>>> + old = rtnl_dereference(dev->qdisc); >>>>>>>> if (new && !new->ops->attach) >>>>>>>> qdisc_refcount_inc(new); >>>>>>>> rcu_assign_pointer(dev->qdisc, new ? : &noop_qdisc); >>>>>>>> >>>>>>>> + notify_and_destroy(net, skb, n, classid, old, new); >>>>>>>> + >>>>>>>> if (new && new->ops->attach) >>>>>>>> new->ops->attach(new); >>>>>>>> } else { >>>>>>> Hi Eric, >>>>>>> We started seeing the following WARN_ON happening on htb destroy >>>>>>> following your patch: >>>>>>> https://elixir.bootlin.com/linux/v6.1-rc3/source/net/sched/sch_htb.c#L1561 >>>>>>> >>>>>>> Anything comes to mind? >>>>>> Not really. Let's ask Maxim Mikityanskiy >>>>> CC: Maxim on non-nvidia address >>>>> >>>> Wild guess is that we need this fix: >>>> >>>> diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c >>>> index e5b4bbf3ce3d5f36edb512d4017ebd97209bb377..f82c07bd3d60e26e5a1fe2b335dbec29aebb602e >>>> 100644 >>>> --- a/net/sched/sch_htb.c >>>> +++ b/net/sched/sch_htb.c >>>> @@ -1558,7 +1558,7 @@ static int htb_destroy_class_offload(struct >>>> Qdisc *sch, struct htb_class *cl, >>>> /* Before HTB is destroyed, the kernel grafts noop_qdisc to >>>> * all queues. >>>> */ >>>> - WARN_ON(!(old->flags & TCQ_F_BUILTIN)); >>>> + WARN_ON(old && !(old->flags & TCQ_F_BUILTIN)); >>> I don't think it's the right fix. If the WARN_ON happens and doesn't >>> complain about old == NULL, it's not NULL, so this extra check won't >>> help. In any case, old comes from dev_graft_qdisc, which should never >>> return NULL. >>> >>> Maybe something changed after Eric's patch, so that the statement >>> above is no longer true? I.e. I expect a noop_qdisc here, but there is >>> some other qdisc attached to the queue. I need to recall what was the >>> destroy flow and what code assigned noop_qdisc there... >> Gal please provide a repro. It is not clear if you get a WARN or a NULL deref. > The WARN_ON is triggering, old is not NULL and old->flags is equal to 0x174. > > It reproduces consistently: > ip link set dev eth2 up > ip addr add 194.237.173.123/16 dev eth2 > tc qdisc add dev eth2 clsact > tc qdisc add dev eth2 root handle 1: htb default 1 offload > tc class add dev eth2 classid 1: parent root htb rate 18000mbit ceil > 22500.0mbit burst 450000kbit cburst 450000kbit > tc class add dev eth2 classid 1:3 parent 1: htb rate 3596mbit burst > 89900kbit cburst 89900kbit > tc qdisc delete dev eth2 clsact > tc qdisc delete dev eth2 root handle 1: htb default 1 > > Please let me know if there's anything else you want me to check. Hi Eric, did you get a chance to take a look?