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 X-Spam-Level: X-Spam-Status: No, score=-20.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2539C433EF for ; Wed, 8 Sep 2021 04:39:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 399ED610FF for ; Wed, 8 Sep 2021 04:39:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 399ED610FF Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=fb.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B738F6B006C; Wed, 8 Sep 2021 00:39:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B242D6B0071; Wed, 8 Sep 2021 00:39:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 94E966B0072; Wed, 8 Sep 2021 00:39:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0082.hostedemail.com [216.40.44.82]) by kanga.kvack.org (Postfix) with ESMTP id 7F0BC6B006C for ; Wed, 8 Sep 2021 00:39:41 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3F1D22C5A1 for ; Wed, 8 Sep 2021 04:39:41 +0000 (UTC) X-FDA: 78563152962.21.81FA1A3 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by imf20.hostedemail.com (Postfix) with ESMTP id BE9FED0000A9 for ; Wed, 8 Sep 2021 04:39:40 +0000 (UTC) Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 1884U7cx006034; Tue, 7 Sep 2021 21:39:27 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=subject : to : cc : references : from : message-id : date : in-reply-to : content-type : content-transfer-encoding : mime-version; s=facebook; bh=CiHSqBgnimKMylyiy+U6Bfi+FRAVApKuCL4LdaKKfHk=; b=pSSeN7kbA4AdlAUibclrTQ76XfjJqapIhi5OKnxSAeukh62mclKubA+Y0+hf2wtVtMkF RPYe3X5vLwLSLVoZ6zk2oBdFapUBavx651nBTeM6Yj6362bV2STdL8yt+Ao+ojZwftoB 4NSRZc1/n/rNvmpPDizWzRuEyY5DHnvtHHE= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3axcq4uw4p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Tue, 07 Sep 2021 21:39:27 -0700 Received: from NAM11-DM6-obe.outbound.protection.outlook.com (100.104.98.9) by o365-in.thefacebook.com (100.104.94.228) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.14; Tue, 7 Sep 2021 21:39:25 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=gp9Cq752NPeFSfveaxn4yAvd9qlLpdIgsbvV3HhvDNh1h2moBjHlZZb4W+UUIGW4N94bjrrCM8q7rzg62hQv3cizzfhilUnMtRWfrFHzQhou2PI+odsfoudkyYvD4Dgnb/wuxeygcrhCo3JXD2HX0eiL7KjT+H0lDqLNYLEmIhCuULG5RbbbMHarR3GvFdwcMNnRb0BrKZpL1d6qr+DI4SHTEPQKn2LsZ8PK3hP2prm3bhbJs2O6lmMGjepfqg6q4yRiae7he76YGk6ptmQKviI5YAYt++kuAy8C147/Vd0+zhTVwwvnSJS74+AvvGufn1r8yvmwtyL56WLPdxa27w== 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; bh=CiHSqBgnimKMylyiy+U6Bfi+FRAVApKuCL4LdaKKfHk=; b=agbR4jkXgQ0AyqfDXQIGcOIvYhDrLCyC9gVrb9n9LkLEBJfhSaeAtSWaybc/38ROopCgpwxAUdr1EaFLdfLfNhLOlczjml8owyg8d00Kf5emEUEUNnO1WMlDEy+VNKt1m4NLr2sC7lkzfkk8AgWUzXGOsBek4r47gpf6Cv/LXUzA2IxrJeoteS8Y7KTAg9CM8qWypgnWlDwKgc5XLYO6QJbZ6JAYUvA1R8PHtyYl1fTJLlQAVJC7dEqe1Nu8FJHkt/Jdx3ZLn5Xa4XxETmSCewopbdzsovIbjCYZ/yOcDAgqxlRHQktx0BFKFl/AfdqcOnKdt0tlj/ffGWof5jOjfQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=fb.com; dmarc=pass action=none header.from=fb.com; dkim=pass header.d=fb.com; arc=none Received: from SN6PR1501MB2064.namprd15.prod.outlook.com (2603:10b6:805:d::27) by SN6PR15MB2255.namprd15.prod.outlook.com (2603:10b6:805:19::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4478.19; Wed, 8 Sep 2021 04:39:19 +0000 Received: from SN6PR1501MB2064.namprd15.prod.outlook.com ([fe80::c143:fac2:85b4:14cb]) by SN6PR1501MB2064.namprd15.prod.outlook.com ([fe80::c143:fac2:85b4:14cb%7]) with mapi id 15.20.4478.025; Wed, 8 Sep 2021 04:39:19 +0000 Subject: Re: [PATCH mm] mm/mmap: relax mmap_assert_locked() for find_vma() To: Liam Howlett CC: "bpf@vger.kernel.org" , "linux-mm@kvack.org" , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , "kernel-team@fb.com" , Luigi Rizzo References: <20210907062650.1309736-1-yhs@fb.com> <20210908030941.rfew4t63fw4s4bpz@revolver> From: Yonghong Song Message-ID: <95576066-0750-2f0f-9886-de00f62abe0e@fb.com> Date: Tue, 7 Sep 2021 21:39:17 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: <20210908030941.rfew4t63fw4s4bpz@revolver> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BYAPR04CA0018.namprd04.prod.outlook.com (2603:10b6:a03:40::31) To SN6PR1501MB2064.namprd15.prod.outlook.com (2603:10b6:805:d::27) MIME-Version: 1.0 Received: from [IPv6:2620:10d:c085:21e8::18c1] (2620:10d:c090:400::5:8117) by BYAPR04CA0018.namprd04.prod.outlook.com (2603:10b6:a03:40::31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4500.14 via Frontend Transport; Wed, 8 Sep 2021 04:39:19 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 27430269-e73a-4d3d-198f-08d972829f62 X-MS-TrafficTypeDiagnostic: SN6PR15MB2255: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-FB-Source: Internal X-MS-Oob-TLC-OOBClassifiers: OLM:10000; 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:SN6PR1501MB2064.namprd15.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(376002)(346002)(366004)(39860400002)(396003)(136003)(478600001)(45080400002)(8676002)(2906002)(2616005)(5660300002)(31696002)(31686004)(66946007)(66476007)(8936002)(4326008)(66556008)(38100700002)(6916009)(316002)(6486002)(54906003)(86362001)(52116002)(36756003)(186003)(53546011)(83380400001)(43740500002)(45980500001);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WnZidkxTcXM2cG91YVNMUjlFSDJYYk4vZ3NWK09Zc0FWcWlGeEovaUtxd0w1?= =?utf-8?B?Qmo2YzBCcGRmbDhyMXF6U0dXM254WXlnUjU5WGp3Nkg3RTdPWkZSL0ZRR20z?= =?utf-8?B?L3o2aUVNSFNXZDF5bWhDMUp1SmlvZTZsWmtWUlhCMnErZmZiVmovaXVna21x?= =?utf-8?B?MkRDV1VMeUpBQkoxY0hOZkpIMlNnQWZ4UWNWU3UxS2lSSWxybElxRDZnTlYz?= =?utf-8?B?ZFEwODI5clg1eFVXVkVjaTUwekRoN1ZTZ09zZGJkdGUxNHlyV2Q1c1dYQnhU?= =?utf-8?B?b210cGRQWUVaMHJrSm5BUVBqbkVWeXl1TitZUU15SVg5a0JLUmZPSHRjK2NK?= =?utf-8?B?SDFsUGM0ekt5UE1iUWkrejcwbnVWakludDNRRDJlN0doeEY0NFB6aTY1QUFD?= =?utf-8?B?QzE3b253S05DcjN5ZDJadXI0SnRzelh5TVQ2bnNtb0RQeUlhQ09sc0hZTmRN?= =?utf-8?B?WDJBamdramkxZWhGaWpDYVdMY1liR0NWaDhNOHMyUjFQUWVoK3lQQW9zR3FV?= =?utf-8?B?bkVIZFFVNG44NlBZWmdIQmhlVFdaSTFxNGwyNUo3UGp3MGpPSE9YNU9WY2NR?= =?utf-8?B?ZjJwSHFDa29UVzdsTnQxK0pzWFBCdzJ4Qk5SK09QZjI2cVpQakhPZ2YyWG83?= =?utf-8?B?Q3hwODQyQXZKUGFTVDV0Qmh2WTd0bnNTV3MxeFlDelBlUmw2UzRpSzFRc2FP?= =?utf-8?B?OWpIdkNZT3FocTBCUEM5RTdZWmxtWUppZWwvWlBiYy8zbVJ2QjhLMlJ6Vncy?= =?utf-8?B?YjU0Z3ZYWWQvenhTQzdmVlVZOUdXT0lCTlUrek1kT2x4UGFIUzBhM3Vubkh4?= =?utf-8?B?R0pqOVcxV1ovSUZ0ZW1YblQrM0dRRE93dzVwY1grRFpORXRiUkxoZFRONTIx?= =?utf-8?B?c0NyNFlUMXk3eThGbWdGMVhPMzlHWTYwZFBZQVJhaFNacnMrVnhGNDkvUDhJ?= =?utf-8?B?a0RObnpUR3JJQ08yUWJ6U1lON2VJTjFBdWx5bmVKcVAyeHlmL3VUZ1JEQm1a?= =?utf-8?B?aDl2bjhSakZ2NUIvLzNPNHJKVFRRaExXMXFoUlBqdTM2NUhYcnBlVkkxdlQv?= =?utf-8?B?VU1GOU9HZEZoZWQ3VGtOVDlpWG52aGt2aU9mcjcwb2VzZE8wbzJISHMxd213?= =?utf-8?B?bC8xeVJnK2hHTnFhRVdnYkdGRHJKcFMzSnhnRDd5M0owMU5ydGMrYnZSdHhJ?= =?utf-8?B?Nnd0ZEhFRWFLY25vVGxCN2lCR01JMmNSTjZvUUE4RWF1MnF4cHVQNUh2WDFm?= =?utf-8?B?cm41Q2Q5NjUvK3NvakdINllTMDV5bGQxNkE1S2dha0xMRkFkMkJ5Z2t1RGlq?= =?utf-8?B?Rit4Qnc2QzRQTGt5cC9XZDhHUThVZ2ZMdlZWbEdvNldmalV3ZW8wRHhQQk9D?= =?utf-8?B?UDJDVkhjaHFJUkFMd1ZDKzRpLzZ1VlljS0Y1WGZSdzFvOWh3cktNREVOM3hO?= =?utf-8?B?eS9TWWV6ZStWL1Q2LzdWMHZJOGhjb3E1OHNlYTFITzVIOTcxbnBpN3Y5cjlt?= =?utf-8?B?TzB2TlYvUzBmRUtCemdCRTU0RytrUVBmODFoT3hsTmVWa1ZIVUpnMWNVc0Jq?= =?utf-8?B?VGlUV3B3bk9wUEh3OWlpRHc4SmROZ1lldmdFNlE2VU0vT1NOUkNXSGRRck0y?= =?utf-8?B?U0Q0U1g2aDFsMzNRdktqVitHTWlMOUQxbHBGYWEzNWxPUGlJZENnQWlVM0Zi?= =?utf-8?B?ekVlQVNhNnluTGQxKzVVTERsUy9lanRnTk5kV2U5TnFPOWhYN1R6UFVFbmtn?= =?utf-8?B?UjFMS2lKU2VJMDRyaGVKbDlsNzNpcDhWY1BaZ09pcXZwSmxMSDlBVzdWeENv?= =?utf-8?B?N1JHVEJFWXp6elR1dzJhZz09?= X-MS-Exchange-CrossTenant-Network-Message-Id: 27430269-e73a-4d3d-198f-08d972829f62 X-MS-Exchange-CrossTenant-AuthSource: SN6PR1501MB2064.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Sep 2021 04:39:19.6286 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: QUJCQMID6uqhwfuQsbChxtB87WC0p8QY0J3J2wq5nsqLX23yE2sQsO0l8068K1gZ X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN6PR15MB2255 X-OriginatorOrg: fb.com X-Proofpoint-GUID: N3AaAPUWLxqnpQJ3WtlFP7nC5XWhCfiE X-Proofpoint-ORIG-GUID: N3AaAPUWLxqnpQJ3WtlFP7nC5XWhCfiE X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-09-08_01:2021-09-07,2021-09-08 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 adultscore=0 spamscore=0 lowpriorityscore=0 bulkscore=0 suspectscore=0 mlxscore=0 impostorscore=0 clxscore=1011 mlxlogscore=999 priorityscore=1501 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109080027 X-FB-Internal: deliver X-Rspamd-Queue-Id: BE9FED0000A9 Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=fb.com header.s=facebook header.b=pSSeN7kb; dmarc=pass (policy=reject) header.from=fb.com; spf=pass (imf20.hostedemail.com: domain of "prvs=8885b17d91=yhs@fb.com" designates 67.231.153.30 as permitted sender) smtp.mailfrom="prvs=8885b17d91=yhs@fb.com" X-Rspamd-Server: rspam01 X-Stat-Signature: k3caxdtp6ufgj6d1m8da4hpias6w7zgp X-HE-Tag: 1631075980-982530 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 9/7/21 8:09 PM, Liam Howlett wrote: > * Yonghong Song [210907 02:27]: >> Current bpf-next bpf selftest "get_stack_raw_tp" triggered the warning: >> >> [ 1411.304463] WARNING: CPU: 3 PID: 140 at include/linux/mmap_lock.h:164 find_vma+0x47/0xa0 >> [ 1411.304469] Modules linked in: bpf_testmod(O) [last unloaded: bpf_testmod] >> [ 1411.304476] CPU: 3 PID: 140 Comm: systemd-journal Tainted: G W O 5.14.0+ #53 >> [ 1411.304479] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 >> [ 1411.304481] RIP: 0010:find_vma+0x47/0xa0 >> [ 1411.304484] Code: de 48 89 ef e8 ba f5 fe ff 48 85 c0 74 2e 48 83 c4 08 5b 5d c3 48 8d bf 28 01 00 00 be ff ff ff ff e8 2d 9f d8 00 85 c0 75 d4 <0f> 0b 48 89 de 48 8 >> [ 1411.304487] RSP: 0018:ffffabd440403db8 EFLAGS: 00010246 >> [ 1411.304490] RAX: 0000000000000000 RBX: 00007f00ad80a0e0 RCX: 0000000000000000 >> [ 1411.304492] RDX: 0000000000000001 RSI: ffffffff9776b144 RDI: ffffffff977e1b0e >> [ 1411.304494] RBP: ffff9cf5c2f50000 R08: ffff9cf5c3eb25d8 R09: 00000000fffffffe >> [ 1411.304496] R10: 0000000000000001 R11: 00000000ef974e19 R12: ffff9cf5c39ae0e0 >> [ 1411.304498] R13: 0000000000000000 R14: 0000000000000000 R15: ffff9cf5c39ae0e0 >> [ 1411.304501] FS: 00007f00ae754780(0000) GS:ffff9cf5fba00000(0000) knlGS:0000000000000000 >> [ 1411.304504] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 1411.304506] CR2: 000000003e34343c CR3: 0000000103a98005 CR4: 0000000000370ee0 >> [ 1411.304508] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> [ 1411.304510] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> [ 1411.304512] Call Trace: >> [ 1411.304517] stack_map_get_build_id_offset+0x17c/0x260 >> [ 1411.304528] __bpf_get_stack+0x18f/0x230 >> [ 1411.304541] bpf_get_stack_raw_tp+0x5a/0x70 >> [ 1411.305752] RAX: 0000000000000000 RBX: 5541f689495641d7 RCX: 0000000000000000 >> [ 1411.305756] RDX: 0000000000000001 RSI: ffffffff9776b144 RDI: ffffffff977e1b0e >> [ 1411.305758] RBP: ffff9cf5c02b2f40 R08: ffff9cf5ca7606c0 R09: ffffcbd43ee02c04 >> [ 1411.306978] bpf_prog_32007c34f7726d29_bpf_prog1+0xaf/0xd9c >> [ 1411.307861] R10: 0000000000000001 R11: 0000000000000044 R12: ffff9cf5c2ef60e0 >> [ 1411.307865] R13: 0000000000000005 R14: 0000000000000000 R15: ffff9cf5c2ef6108 >> [ 1411.309074] bpf_trace_run2+0x8f/0x1a0 >> [ 1411.309891] FS: 00007ff485141700(0000) GS:ffff9cf5fae00000(0000) knlGS:0000000000000000 >> [ 1411.309896] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 1411.311221] syscall_trace_enter.isra.20+0x161/0x1f0 >> [ 1411.311600] CR2: 00007ff48514d90e CR3: 0000000107114001 CR4: 0000000000370ef0 >> [ 1411.312291] do_syscall_64+0x15/0x80 >> [ 1411.312941] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> [ 1411.313803] entry_SYSCALL_64_after_hwframe+0x44/0xae >> [ 1411.314223] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> [ 1411.315082] RIP: 0033:0x7f00ad80a0e0 >> [ 1411.315626] Call Trace: >> [ 1411.315632] stack_map_get_build_id_offset+0x17c/0x260 >> >> To reproduce, first build `test_progs` binary: >> make -C tools/testing/selftests/bpf -j60 >> and then run the binary at tools/testing/selftests/bpf directory: >> ./test_progs -t get_stack_raw_tp >> >> The warning is due to commit 5b78ed24e8ec("mm/pagemap: add mmap_assert_locked() annotations to find_vma*()") >> which added mmap_assert_locked() in find_vma() function. The mmap_assert_locked() function >> asserts that mm->mmap_lock needs to be held. But this is not the case for >> bpf_get_stack() or bpf_get_stackid() helper (kernel/bpf/stackmap.c), which >> uses mmap_read_trylock_non_owner() instead. Since mm->mmap_lock is not held >> in bpf_get_stack[id]() use case, the above warning is emitted during test run. >> >> This patch fixed the issue by replacing mmap_assert_locked() with rwsem_is_locked(&mm->mmap_lock) >> in find_vma(). > > I'm not a fan of removing the lockdep check. I'd rather see find_vma() > do the lockdep and call another internal function which does exactly > what you have below. Then you could call the one and everyone else > could keep the code they have. Okay, will do that in the next revision. > > More importantly, since this is the only user of the > mmap_read_trylock_non_owner(), is there a build bot that could be used > to catch errors introduced in this > path? We do have libbpf ci to test selftest against current *bpf_next* and some past old kernels. In this case, I think it is linux-next first introduced issue, and then the change went to net-next and then bpf-next. So to catch this earlier, we need to do libbpf ci on linux-next and/or net-next. We will discuss how we could incorporate this. > > Thanks, > Liam > >> >> Cc: Luigi Rizzo >> Fixes: 5b78ed24e8ec("mm/pagemap: add mmap_assert_locked() annotations to find_vma*()") >> Signed-off-by: Yonghong Song >> --- >> mm/mmap.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> Alternatively we could add a bool argument to find_vma to indicate whether >> mm->mmap_lock has been held or not. But I would like to report and try the >> simpler solution first. >> >> diff --git a/mm/mmap.c b/mm/mmap.c >> index 88dcc5c25225..8c78b85475b1 100644 >> --- a/mm/mmap.c >> +++ b/mm/mmap.c >> @@ -2275,7 +2275,7 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) >> struct rb_node *rb_node; >> struct vm_area_struct *vma; >> >> - mmap_assert_locked(mm); >> + VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm); >> /* Check the cache first. */ >> vma = vmacache_find(mm, addr); >> if (likely(vma)) >> -- >> 2.30.2 >>