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,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 1E988C3A5A4 for ; Thu, 22 Aug 2019 17:40:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E78F823402 for ; Thu, 22 Aug 2019 17:40:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566495624; bh=6KUXWNDA8/+Pde2MDNRP2/6V1yRx83M8Ry5DX+w5b6U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kHcIRk3pWAaxK87bYEhqv9AhsxSpxI1KdPFb9S8OSKi6MHYWF7HkWHsLJ1yiXUFiw gSz+qZGKrhOZGPHgLQ45UCJLu9YJIbPhuM59VcouIAJ5Yo9oBG+d/Z5w/92uICMdWp xoJKKDBOiSTQtL6mmA5JvriLLKJEU5iv2K39hCCA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404083AbfHVRYH (ORCPT ); Thu, 22 Aug 2019 13:24:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:41576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391556AbfHVRWt (ORCPT ); Thu, 22 Aug 2019 13:22:49 -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 8AC74233FE; Thu, 22 Aug 2019 17:22:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566494568; bh=6KUXWNDA8/+Pde2MDNRP2/6V1yRx83M8Ry5DX+w5b6U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t8T9IeOEzdB5bcmc3C1nto/O6YpadIn40vq5p+7G1WD+hvjx+lkyveEj86TTuyUc8 KUexa4nen13A5BORvuI0PQJ55NI0vWMaOiaJPCatfIiPOInhk9ghXooZGIx5SIgSzE dMCoNmAKsnpqXtQDG4nh38lDxE7kI4Ttq5xTx+iw= 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 4.4 58/78] usb: cdc-acm: make sure a refcount is taken early enough Date: Thu, 22 Aug 2019 10:19:02 -0700 Message-Id: <20190822171833.717553055@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190822171832.012773482@linuxfoundation.org> References: <20190822171832.012773482@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 | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1319,13 +1319,6 @@ made_compressed_probe: if (acm == NULL) goto alloc_fail; - minor = acm_alloc_minor(acm); - if (minor < 0) { - dev_err(&intf->dev, "no more free acm devices\n"); - kfree(acm); - return -ENODEV; - } - ctrlsize = usb_endpoint_maxp(epctrl); readsize = usb_endpoint_maxp(epread) * (quirks == SINGLE_RX_URB ? 1 : 2); @@ -1333,6 +1326,16 @@ 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) { + dev_err(&intf->dev, "no more free acm devices\n"); + kfree(acm); + return -ENODEV; + } + acm->minor = minor; acm->dev = usb_dev; acm->ctrl_caps = ac_management_function; @@ -1474,7 +1477,6 @@ 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)) {