From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-db5eur01on0124.outbound.protection.outlook.com ([104.47.2.124]:22704 "EHLO EUR01-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751799AbeBZJkp (ORCPT ); Mon, 26 Feb 2018 04:40:45 -0500 Subject: Re: [lkp-robot] [net] 37b927536f: kernel_BUG_at_net/core/net_namespace.c To: kernel test robot Cc: davem@davemloft.net, vyasevic@redhat.com, kstewart@linuxfoundation.org, pombredanne@nexb.com, vyasevich@gmail.com, mark.rutland@arm.com, gregkh@linuxfoundation.org, adobriyan@gmail.com, fw@strlen.de, nicolas.dichtel@6wind.com, xiyou.wangcong@gmail.com, roman.kapl@sysgo.com, paul@paul-moore.com, dsahern@gmail.com, daniel@iogearbox.net, lucien.xin@gmail.com, mschiffer@universe-factory.net, rshearma@brocade.com, netdev@vger.kernel.org, ebiederm@xmission.com, avagin@virtuozzo.com, gorcunov@virtuozzo.com, eric.dumazet@gmail.com, stephen@networkplumber.org, lkp@01.org References: <20180226020446.GC3019@yexl-desktop> From: Kirill Tkhai Message-ID: <7f32f11e-ed61-5a90-d8f1-63511959ae70@virtuozzo.com> Date: Mon, 26 Feb 2018 12:40:33 +0300 MIME-Version: 1.0 In-Reply-To: <20180226020446.GC3019@yexl-desktop> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org List-ID: On 26.02.2018 05:04, kernel test robot wrote: > > FYI, we noticed the following commit (built with gcc-7): > > commit: 37b927536f46b27de240934db9580c3d3eba9937 ("net: Introduce net_sem for protection of pernet_list") > url: https://github.com/0day-ci/linux/commits/Kirill-Tkhai/Replacing-net_mutex-with-rw_semaphore/20180215-064145 > > > 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 -m 512M > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > > > +------------------------------------------+------------+------------+ > | | b6d8347bf7 | 37b927536f | > +------------------------------------------+------------+------------+ > | boot_successes | 8 | 0 | > | boot_failures | 0 | 8 | > | kernel_BUG_at_net/core/net_namespace.c | 0 | 8 | > | invalid_opcode:#[##] | 0 | 8 | > | RIP:ops_init | 0 | 8 | > | Kernel_panic-not_syncing:Fatal_exception | 0 | 8 | > +------------------------------------------+------------+------------+ > > > > [ 0.258559] kernel BUG at net/core/net_namespace.c:73! > [ 0.260018] invalid opcode: 0000 [#1] > [ 0.261073] Modules linked in: > [ 0.262005] CPU: 0 PID: 1 Comm: swapper Not tainted 4.15.0-05871-g37b9275 #1 > [ 0.263875] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 > [ 0.266084] RIP: 0010:ops_init+0x101/0x120 > [ 0.267233] RSP: 0000:ffffc9000000be00 EFLAGS: 00010246 > [ 0.268647] RAX: 0000000000000000 RBX: ffffffff823280a0 RCX: 0000000000000000 > [ 0.270000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88001c602180 > [ 0.270000] RBP: ffff88001c602140 R08: ffffffff82323d00 R09: ffff88001c602140 > [ 0.270000] R10: ffffffff82323308 R11: ffffffff827ff64d R12: ffffffff82323400 > [ 0.270000] R13: 0000000000000003 R14: ffffffff826e17b9 R15: 0000000000000000 > [ 0.270000] FS: 0000000000000000(0000) GS:ffffffff82235000(0000) knlGS:0000000000000000 > [ 0.270000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.270000] CR2: 0000000000000000 CR3: 0000000002213000 CR4: 00000000000006b0 > [ 0.270000] Call Trace: > [ 0.270000] ? set_debug_rodata+0x11/0x11 > [ 0.270000] register_pernet_operations+0x101/0x1e0 > [ 0.270000] register_pernet_subsys+0x24/0x40 > [ 0.270000] netlink_proto_init+0x143/0x160 > [ 0.270000] ? eth_offload_init+0x14/0x14 > [ 0.270000] do_one_initcall+0x4d/0x190 > [ 0.270000] kernel_init_freeable+0x10e/0x190 > [ 0.270000] ? rest_init+0xa0/0xa0 > [ 0.270000] kernel_init+0xa/0xf0 > [ 0.270000] ret_from_fork+0x3a/0x50 > [ 0.270000] Code: 8d 14 c5 e8 ff ff ff e8 be 14 11 00 4b 89 2c ef 49 8d 7e 08 4d 89 bc 24 50 06 00 00 be 08 00 00 00 e8 34 22 95 ff e9 77 ff ff ff <0f> 0b 0f 0b b8 f4 ff ff ff eb 91 b8 f4 ff ff ff e9 77 ff ff ff > [ 0.270000] RIP: ops_init+0x101/0x120 RSP: ffffc9000000be00 > [ 0.270013] ---[ end trace e0045ead2b146f98 ]--- There was the check: BUG_ON(!mutex_is_locked(&net_mutex)); which was killed in one of next commits of this patchset: commit 447cd7a0d7d1e5b4486e99cce289654fec9951e3 Author: Kirill Tkhai Date: Tue Feb 13 12:26:44 2018 +0300 net: Allow pernet_operations to be executed in parallel So, the whole patchset as an atomic change is safe; and the only thing is the hunk removing the BUG_ON() had to go in another patch. Anyway, thanks for testing, Xiaolong. Kirill