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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 44D3EC3A5A1 for ; Thu, 22 Aug 2019 17:26:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12143206DD for ; Thu, 22 Aug 2019 17:26:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566494791; bh=oylRR7tSe0koEcCNyDNiwT/AtGRhGuiECLpAT7wlnAU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ltdV7xpM+kaBhYmIM9DXKyGx0sHZGzo58K0ShR7ROeaMxt1UIxsqbi5Zuz1TMZ+eq mZsSCJXOAzb/B+tZuoFSPpRDbeGiYk1caDgEEa7nhn7LRqcMe4q8DImJfXW3ol1dWh cU3JOeieHmqWWF0iyLNemN0iXaBPQXBV+r2ko2OY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391831AbfHVR02 (ORCPT ); Thu, 22 Aug 2019 13:26:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:48392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404379AbfHVRZT (ORCPT ); Thu, 22 Aug 2019 13:25:19 -0400 Received: from localhost (wsip-184-188-36-2.sd.sd.cox.net [184.188.36.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CF0282341F; Thu, 22 Aug 2019 17:25:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566494719; bh=oylRR7tSe0koEcCNyDNiwT/AtGRhGuiECLpAT7wlnAU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p1HpBHuOZp8TjmXkyhntQ0O+Q2r4G3zF56KMI1Oq0uIrdrasmNRrAjAIoBNzC69er hK6jVaIxfE+RYSVqQVJd7s2OCB/WyT85k/mMIYNmTK3RJjw7UHONehEzIEgS8GSEJL aZrqABfm9RX+juNA5+E0+0R7m8Zuqv10Ed61HExI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver Neukum , syzbot+1b2449b7b5dc240d107a@syzkaller.appspotmail.com Subject: [PATCH 4.14 48/71] usb: cdc-acm: make sure a refcount is taken early enough Date: Thu, 22 Aug 2019 10:19:23 -0700 Message-Id: <20190822171729.936606642@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190822171726.131957995@linuxfoundation.org> References: <20190822171726.131957995@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oliver Neukum commit c52873e5a1ef72f845526d9f6a50704433f9c625 upstream. destroy() will decrement the refcount on the interface, so that it needs to be taken so early that it never undercounts. Fixes: 7fb57a019f94e ("USB: cdc-acm: Fix potential deadlock (lockdep warning)") Cc: stable Reported-and-tested-by: syzbot+1b2449b7b5dc240d107a@syzkaller.appspotmail.com Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20190808142119.7998-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1342,10 +1342,6 @@ made_compressed_probe: if (acm == NULL) goto alloc_fail; - minor = acm_alloc_minor(acm); - if (minor < 0) - goto alloc_fail1; - ctrlsize = usb_endpoint_maxp(epctrl); readsize = usb_endpoint_maxp(epread) * (quirks == SINGLE_RX_URB ? 1 : 2); @@ -1353,6 +1349,13 @@ made_compressed_probe: acm->writesize = usb_endpoint_maxp(epwrite) * 20; acm->control = control_interface; acm->data = data_interface; + + usb_get_intf(acm->control); /* undone in destruct() */ + + minor = acm_alloc_minor(acm); + if (minor < 0) + goto alloc_fail1; + acm->minor = minor; acm->dev = usb_dev; if (h.usb_cdc_acm_descriptor) @@ -1501,7 +1504,6 @@ skip_countries: usb_driver_claim_interface(&acm_driver, data_interface, acm); usb_set_intfdata(data_interface, acm); - usb_get_intf(control_interface); tty_dev = tty_port_register_device(&acm->port, acm_tty_driver, minor, &control_interface->dev); if (IS_ERR(tty_dev)) {