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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 2A700C2D0E4 for ; Fri, 20 Nov 2020 16:56:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1C452100A for ; Fri, 20 Nov 2020 16:56:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730196AbgKTQ4L (ORCPT ); Fri, 20 Nov 2020 11:56:11 -0500 Received: from netrider.rowland.org ([192.131.102.5]:55997 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1730139AbgKTQ4K (ORCPT ); Fri, 20 Nov 2020 11:56:10 -0500 Received: (qmail 621944 invoked by uid 1000); 20 Nov 2020 11:56:09 -0500 Date: Fri, 20 Nov 2020 11:56:09 -0500 From: Alan Stern To: syzbot Cc: balbi@kernel.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: memory leak in hub_event Message-ID: <20201120165609.GE619708@rowland.harvard.edu> References: <00000000000014163805b48b5063@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00000000000014163805b48b5063@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 20, 2020 at 07:15:20AM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 4d02da97 Merge tag 'net-5.10-rc5' of git://git.kernel.org/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13a7d2b6500000 > kernel config: https://syzkaller.appspot.com/x/.config?x=c5353ac514ca5a43 > dashboard link: https://syzkaller.appspot.com/bug?extid=44e64397bd81d5e84cba > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14925089500000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16810051500000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+44e64397bd81d5e84cba@syzkaller.appspotmail.com > > BUG: memory leak > unreferenced object 0xffff88810d5ff800 (size 2048): > comm "kworker/1:0", pid 17, jiffies 4294949188 (age 14.280s) > hex dump (first 32 bytes): > ff ff ff ff 31 00 00 00 00 00 00 00 00 00 00 00 ....1........... > 00 00 00 00 00 00 00 00 00 00 00 00 03 00 00 00 ................ > backtrace: > [<00000000f0428224>] kmalloc include/linux/slab.h:552 [inline] > [<00000000f0428224>] kzalloc include/linux/slab.h:664 [inline] > [<00000000f0428224>] usb_alloc_dev+0x32/0x450 drivers/usb/core/usb.c:582 > [<000000001802b3dd>] hub_port_connect drivers/usb/core/hub.c:5128 [inline] > [<000000001802b3dd>] hub_port_connect_change drivers/usb/core/hub.c:5362 [inline] > [<000000001802b3dd>] port_event drivers/usb/core/hub.c:5508 [inline] > [<000000001802b3dd>] hub_event+0x118d/0x20d0 drivers/usb/core/hub.c:5590 > [<0000000092d3650d>] process_one_work+0x27d/0x590 kernel/workqueue.c:2272 > [<00000000d4629ab0>] worker_thread+0x59/0x5d0 kernel/workqueue.c:2418 > [<000000003c358b45>] kthread+0x178/0x1b0 kernel/kthread.c:292 > [<000000003689dbb0>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 This looks like a reference is being taken but not released. Hard to tell where it's happening, though. Let's try to narrow it down. Alan Stern #syz test: upstream 4d02da97 Index: usb-devel/drivers/media/usb/gspca/gspca.c =================================================================== --- usb-devel.orig/drivers/media/usb/gspca/gspca.c +++ usb-devel/drivers/media/usb/gspca/gspca.c @@ -1489,6 +1489,8 @@ int gspca_dev_probe2(struct usb_interfac } gspca_dev->v4l2_dev.release = gspca_release; + ret = -EIO; + goto out; ret = v4l2_device_register(&intf->dev, &gspca_dev->v4l2_dev); if (ret) goto out;