From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============0282790738636533144==" MIME-Version: 1.0 From: Toke Høiland-Jørgensen To: lkp@lists.01.org Subject: Re: [xdp] 9cb54e254c: kernel/bpf/devmap.c:#suspicious_rcu_dereference_check() Date: Wed, 10 Apr 2019 12:00:58 +0200 Message-ID: <87r2aaw55x.fsf@toke.dk> In-Reply-To: <20190410075954.GC17122@shao2-debian> List-Id: --===============0282790738636533144== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable kernel test robot writes: > FYI, we noticed the following commit (built with gcc-7): > > commit: 9cb54e254ca479ce636857a1fd1e1a3e9f8796b1 ("[PATCH net-next v4 4/6= ] xdp: Always use a devmap for XDP_REDIRECT to a device") > url: https://github.com/0day-ci/linux/commits/Toke-H-iland-J-rgensen/xdp-= Use-a-default-map-for-xdp_redirect-helper/20190409-161851 > > > in testcase: trinity > with following parameters: > > runtime: 300s > > test-description: Trinity is a linux system call fuzz tester. > test-url: http://codemonkey.org.uk/projects/trinity/ > > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -= m 8G > > caused below changes (please refer to attached dmesg/kmsg for entire log/= backtrace): > > > +--------------------------------------------------------------+---------= ---+------------+ > | | c76c6654= 40 | 9cb54e254c | > +--------------------------------------------------------------+---------= ---+------------+ > | boot_successes | 0 = | 0 | > | boot_failures | 40 = | 38 | > | BUG:kernel_reboot-without-warning_in_test_stage | 28 = | 10 | > | BUG:kernel_hang_in_boot_stage | 12 = | 12 | > | WARNING:suspicious_RCU_usage | 0 = | 16 | > | kernel/bpf/devmap.c:#suspicious_rcu_dereference_check()usage | 0 = | 16 | > +--------------------------------------------------------------+---------= ---+------------+ > > > > [ 413.653218] WARNING: suspicious RCU usage > [ 413.654564] 5.1.0-rc4-00599-g9cb54e2 #43 Tainted: G T > [ 413.656563] ----------------------------- > [ 413.657808] kernel/bpf/devmap.c:807 suspicious rcu_dereference_check()= usage! > [ 413.660285] = > [ 413.660285] other info that might help us debug this: > [ 413.660285] = > [ 413.662614] = > [ 413.662614] rcu_scheduler_active =3D 2, debug_locks =3D 1 > [ 413.664483] 2 locks held by trinity-c3/2248: > [ 413.665800] #0: 00000000713e8e50 (&f->f_pos_lock){+.+.}, at: __fdget_= pos+0x81/0x90 > [ 413.668184] #1: 000000005e54a26c (&p->lock){+.+.}, at: seq_lseek+0x42= /0x1c0 > [ 413.670412] = > [ 413.670412] stack backtrace: > [ 413.671876] CPU: 0 PID: 2248 Comm: trinity-c3 Tainted: G = T 5.1.0-rc4-00599-g9cb54e2 #43 > [ 413.674557] Call Trace: > [ 413.675374] dump_stack+0x1e/0x28 > [ 413.676366] lockdep_rcu_suspicious+0xc6/0xd0 > [ 413.677802] dev_map_default_show+0x84/0xd0 Ah, right, seems I forgot an rcu_read_lock() here. Will fix :) -Toke --===============0282790738636533144==-- 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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED 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 9DC9AC10F14 for ; Wed, 10 Apr 2019 10:01:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7688A2133D for ; Wed, 10 Apr 2019 10:01:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729075AbfDJKBD (ORCPT ); Wed, 10 Apr 2019 06:01:03 -0400 Received: from mail-lf1-f66.google.com ([209.85.167.66]:43010 "EHLO mail-lf1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726494AbfDJKBC (ORCPT ); Wed, 10 Apr 2019 06:01:02 -0400 Received: by mail-lf1-f66.google.com with SMTP id g7so1328855lfh.10 for ; Wed, 10 Apr 2019 03:01:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=KzJDW3WJV2hOrFAxGOF2965hJbMvrNPR3inf4tGe8BA=; b=hVsQ92RwryYjXitX6B/C2GfCylRoYTQAJsVvSS7rnKqr1CYo4Sn42qwp75L9an+QVu MBB5J48HGDF1ChNNts8HWM1FY6lwVoReqUcdqz4hnFEbfVkNdi/NS+2r/Ep3UgZampdj GgCzLTLRQKxVMK96asTG95rqHM1g1hhZyqyQSYdY7T1PsnvXRSC4ANsvnS+l1Ycbv0QR dnl9tZIuqfeAeNflJ2pesVWv+RqFlcyqrKuWGsL6C3GHnu71/jxrJ9EUPTYJAbIueaN+ IDqLSR8Edh2ZrKC9ZuEaRcSnNf4jhuoQWJK1BXRIOZhzqUH9fRSz9ohxsPmoD04ZZVkj q9Pg== X-Gm-Message-State: APjAAAU47mJcN8l06m/CSBa/cVWHb3wP3sxsYXySzUIRo+fYOf8dgqe2 SwrO3by/7eq0FARANzSplOqJbg== X-Google-Smtp-Source: APXvYqz2MC8uGzfKI136OZGxfSbjmMfovZ2ogs5amtCJe3bl+J5gfa8RKyB+b3UehujPdlmsYu91hw== X-Received: by 2002:ac2:4357:: with SMTP id o23mr1365744lfl.146.1554890460556; Wed, 10 Apr 2019 03:01:00 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk (alrua-x1.vpn.toke.dk. [2a00:7660:6da:10::2]) by smtp.gmail.com with ESMTPSA id v28sm385463lfi.33.2019.04.10.03.00.59 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 10 Apr 2019 03:00:59 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 88A7F1804A4; Wed, 10 Apr 2019 12:00:58 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: kernel test robot Cc: David Miller , netdev@vger.kernel.org, Jesper Dangaard Brouer , Daniel Borkmann , Alexei Starovoitov , Jakub Kicinski , =?utf-8?B?QmrDtnJuVMO2cGVs?= , lkp@01.org Subject: Re: [xdp] 9cb54e254c: kernel/bpf/devmap.c:#suspicious_rcu_dereference_check() In-Reply-To: <20190410075954.GC17122@shao2-debian> References: <20190410075954.GC17122@shao2-debian> X-Clacks-Overhead: GNU Terry Pratchett Date: Wed, 10 Apr 2019 12:00:58 +0200 Message-ID: <87r2aaw55x.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org kernel test robot writes: > FYI, we noticed the following commit (built with gcc-7): > > commit: 9cb54e254ca479ce636857a1fd1e1a3e9f8796b1 ("[PATCH net-next v4 4/6] xdp: Always use a devmap for XDP_REDIRECT to a device") > url: https://github.com/0day-ci/linux/commits/Toke-H-iland-J-rgensen/xdp-Use-a-default-map-for-xdp_redirect-helper/20190409-161851 > > > in testcase: trinity > with following parameters: > > runtime: 300s > > test-description: Trinity is a linux system call fuzz tester. > test-url: http://codemonkey.org.uk/projects/trinity/ > > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > > > +--------------------------------------------------------------+------------+------------+ > | | c76c665440 | 9cb54e254c | > +--------------------------------------------------------------+------------+------------+ > | boot_successes | 0 | 0 | > | boot_failures | 40 | 38 | > | BUG:kernel_reboot-without-warning_in_test_stage | 28 | 10 | > | BUG:kernel_hang_in_boot_stage | 12 | 12 | > | WARNING:suspicious_RCU_usage | 0 | 16 | > | kernel/bpf/devmap.c:#suspicious_rcu_dereference_check()usage | 0 | 16 | > +--------------------------------------------------------------+------------+------------+ > > > > [ 413.653218] WARNING: suspicious RCU usage > [ 413.654564] 5.1.0-rc4-00599-g9cb54e2 #43 Tainted: G T > [ 413.656563] ----------------------------- > [ 413.657808] kernel/bpf/devmap.c:807 suspicious rcu_dereference_check() usage! > [ 413.660285] > [ 413.660285] other info that might help us debug this: > [ 413.660285] > [ 413.662614] > [ 413.662614] rcu_scheduler_active = 2, debug_locks = 1 > [ 413.664483] 2 locks held by trinity-c3/2248: > [ 413.665800] #0: 00000000713e8e50 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x81/0x90 > [ 413.668184] #1: 000000005e54a26c (&p->lock){+.+.}, at: seq_lseek+0x42/0x1c0 > [ 413.670412] > [ 413.670412] stack backtrace: > [ 413.671876] CPU: 0 PID: 2248 Comm: trinity-c3 Tainted: G T 5.1.0-rc4-00599-g9cb54e2 #43 > [ 413.674557] Call Trace: > [ 413.675374] dump_stack+0x1e/0x28 > [ 413.676366] lockdep_rcu_suspicious+0xc6/0xd0 > [ 413.677802] dev_map_default_show+0x84/0xd0 Ah, right, seems I forgot an rcu_read_lock() here. Will fix :) -Toke