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DM8PR11MB5734.namprd11.prod.outlook.com ([fe80::51b7:91e3:7c34:57a5]) by DM8PR11MB5734.namprd11.prod.outlook.com ([fe80::51b7:91e3:7c34:57a5%3]) with mapi id 15.20.4500.019; Tue, 14 Sep 2021 03:13:41 +0000 Subject: Re: [syzbot] memory leak in blk_iolatency_init To: syzbot , axboe@kernel.dk, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tj@kernel.org References: <0000000000004ee28405cbe8d287@google.com> From: "Xu, Yanfei" Message-ID: <5feaeb5d-a0c7-ac9a-7511-19c993a5a78e@windriver.com> Date: Tue, 14 Sep 2021 11:13:32 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 In-Reply-To: <0000000000004ee28405cbe8d287@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: HKAPR03CA0026.apcprd03.prod.outlook.com (2603:1096:203:c9::13) To DM8PR11MB5734.namprd11.prod.outlook.com (2603:10b6:8:31::22) 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X-Proofpoint-ORIG-GUID: y8wcOycSIAIA_k4RVhNU92f6SPe_ACLB X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.182.1,Aquarius:18.0.790,Hydra:6.0.391,FMLib:17.0.607.475 definitions=2021-09-13_09,2021-09-09_01,2020-04-07_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 phishscore=0 mlxlogscore=999 lowpriorityscore=0 priorityscore=1501 impostorscore=0 spamscore=0 clxscore=1011 suspectscore=0 bulkscore=0 malwarescore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109140017 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 9/14/21 7:28 AM, syzbot wrote: > [Please note: This e-mail is from an EXTERNAL e-mail address] > > Hello, > > syzbot found the following issue on: > > HEAD commit: a3fa7a101dcf Merge branches 'akpm' and 'akpm-hotfixes' (pa.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=12b4a5b3300000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9ee3a4c022ccbbca > dashboard link: https://syzkaller.appspot.com/bug?extid=01321b15cc98e6bf96d6 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148c170b300000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+01321b15cc98e6bf96d6@syzkaller.appspotmail.com > > 2021/09/09 22:14:31 executed programs: 444 > BUG: memory leak > unreferenced object 0xffff888129acdb80 (size 96): > comm "syz-executor.1", pid 12661, jiffies 4294962682 (age 15.220s) > hex dump (first 32 bytes): > 20 47 c9 85 ff ff ff ff 20 d4 8e 29 81 88 ff ff G...... ..).... > 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [] kmalloc include/linux/slab.h:591 [inline] > [] kzalloc include/linux/slab.h:721 [inline] > [] blk_iolatency_init+0x28/0x190 block/blk-iolatency.c:724 > [] blkcg_init_queue+0xb4/0x1c0 block/blk-cgroup.c:1185 > [] blk_alloc_queue+0x22a/0x2e0 block/blk-core.c:566 > [] blk_mq_init_queue_data block/blk-mq.c:3100 [inline] > [] __blk_mq_alloc_disk+0x25/0xd0 block/blk-mq.c:3124 > [] loop_add+0x1c3/0x360 drivers/block/loop.c:2344 > [] loop_control_get_free drivers/block/loop.c:2501 [inline] > [] loop_control_ioctl+0x17e/0x2e0 drivers/block/loop.c:2516 > [] vfs_ioctl fs/ioctl.c:51 [inline] > [] __do_sys_ioctl fs/ioctl.c:874 [inline] > [] __se_sys_ioctl fs/ioctl.c:860 [inline] > [] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:860 > [] 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+0x44/0xae > > Hi Jens, How about this fix? Once blk_throtl_init() queue init failed, blkcg_iolatency_exit() will not be invoked for cleanup. That leads a memory leak. Swap the blk_throtl_init() and blk_iolatency_init() calls can solve this. Reported-by: syzbot+01321b15cc98e6bf96d6@syzkaller.appspotmail.com Fixes: 19688d7f9592 (block/blk-cgroup: Swap the blk_throtl_init() and blk_iolatency_init() calls) Signed-off-by: Yanfei Xu diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 3c88a79a319b..1ded4181a6de 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1182,10 +1182,6 @@ int blkcg_init_queue(struct request_queue *q) if (preloaded) radix_tree_preload_end(); - ret = blk_iolatency_init(q); - if (ret) - goto err_destroy_all; - ret = blk_ioprio_init(q); if (ret) goto err_destroy_all; @@ -1194,6 +1190,12 @@ int blkcg_init_queue(struct request_queue *q) if (ret) goto err_destroy_all; + ret = blk_iolatency_init(q); + if (ret) { + blk_throtl_exit(q); + goto err_destroy_all; + } + return 0; > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches >