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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 BB3A7C18E5F for ; Sun, 8 Mar 2020 08:18:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85C652072A for ; Sun, 8 Mar 2020 08:18:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726213AbgCHISm convert rfc822-to-8bit (ORCPT ); Sun, 8 Mar 2020 04:18:42 -0400 Received: from coyote.holtmann.net ([212.227.132.17]:35823 "EHLO mail.holtmann.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725306AbgCHISm (ORCPT ); Sun, 8 Mar 2020 04:18:42 -0400 Received: from marcel-macbook.fritz.box (p4FEFC5A7.dip0.t-ipconnect.de [79.239.197.167]) by mail.holtmann.org (Postfix) with ESMTPSA id 29982CED15; Sun, 8 Mar 2020 09:28:08 +0100 (CET) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3608.60.0.2.5\)) Subject: Re: [PATCH] bluetooth/rfcomm: fix ODEBUG bug in rfcomm_dev_ioctl From: Marcel Holtmann In-Reply-To: <1583589488-22450-1-git-send-email-hqjagain@gmail.com> Date: Sun, 8 Mar 2020 09:18:39 +0100 Cc: Johan Hedberg , "David S. Miller" , Jakub Kicinski , Bluez mailing list , netdev , linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: <449B4F83-8BCD-413C-823B-C7A5554801FB@holtmann.org> References: <1583589488-22450-1-git-send-email-hqjagain@gmail.com> To: Qiujun Huang X-Mailer: Apple Mail (2.3608.60.0.2.5) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Qiujun, > Needn't call 'rfcomm_dlc_put' here, because 'rfcomm_dlc_exists' didn't > increase dlc->refcnt. > > Reported-by: syzbot+4496e82090657320efc6@syzkaller.appspotmail.com > Signed-off-by: Qiujun Huang > --- > net/bluetooth/rfcomm/tty.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c > index 0c7d31c..ea2a1df0 100644 > --- a/net/bluetooth/rfcomm/tty.c > +++ b/net/bluetooth/rfcomm/tty.c > @@ -414,7 +414,6 @@ static int __rfcomm_create_dev(struct sock *sk, void __user *arg) > if (IS_ERR(dlc)) > return PTR_ERR(dlc); > else if (dlc) { > - rfcomm_dlc_put(dlc); > return -EBUSY; > } > dlc = rfcomm_dlc_alloc(GFP_KERNEL); Please see the proposed change from Hillf. It is better to not bother with the else if here since the if statement will already leave the function. if (dlc) return -EBUSY; Regards Marcel