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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0267BC433EF for ; Fri, 1 Jul 2022 06:19:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232695AbiGAGS7 (ORCPT ); Fri, 1 Jul 2022 02:18:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234806AbiGAGSm (ORCPT ); Fri, 1 Jul 2022 02:18:42 -0400 Received: from mta-64-225.siemens.flowmailer.net (mta-64-225.siemens.flowmailer.net [185.136.64.225]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C390F35DE6 for ; Thu, 30 Jun 2022 23:18:39 -0700 (PDT) Received: by mta-64-225.siemens.flowmailer.net with ESMTPSA id 20220701061839acf41b8db0c237fcfc for ; Fri, 01 Jul 2022 08:18:39 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=fm1; d=siemens.com; i=daniel.starke@siemens.com; h=Date:From:Subject:To:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:Cc:References:In-Reply-To; bh=KMvuX+r54T3mmQTIXIkVOy+qEFTUWVI0Nmhk8CwSFBU=; b=FeI8ctky519DNMWB0qXrO4yPPdhydoT8vVIUvUwbolwucptsjuMJBfgiF5M8bY553+TN30 OECFsEylH2+xN00i6igDjsgatAgfAWtWwG6v0CiQd29MDKIZ2AzvqnC/qItuWpLm/xaeU6L3 B6CiwWBvxeoXzGs5Fl0zpNIam3Neg=; From: "D. Starke" To: linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org Cc: linux-kernel@vger.kernel.org, Daniel Starke Subject: [PATCH v4 8/9] tty: n_gsm: fix resource allocation order in gsm_activate_mux() Date: Fri, 1 Jul 2022 08:16:51 +0200 Message-Id: <20220701061652.39604-8-daniel.starke@siemens.com> In-Reply-To: <20220701061652.39604-1-daniel.starke@siemens.com> References: <20220701061652.39604-1-daniel.starke@siemens.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Flowmailer-Platform: Siemens Feedback-ID: 519:519-314044:519-21489:flowmailer Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Daniel Starke Within gsm_activate_mux() all timers and locks are initiated before the actual resource for the control channel is allocated. This can lead to race conditions. Allocate the control channel DLCI object first to avoid race conditions. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Daniel Starke --- drivers/tty/n_gsm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) Stable backport remark has been removed compared to v3. No other changes applied. Link: https://lore.kernel.org/all/20220530144512.2731-8-daniel.starke@siemens.com/ diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 9e4ada510c9f..b0b093e8e9d9 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2483,6 +2483,10 @@ static int gsm_activate_mux(struct gsm_mux *gsm) struct gsm_dlci *dlci; int ret; + dlci = gsm_dlci_alloc(gsm, 0); + if (dlci == NULL) + return -ENOMEM; + timer_setup(&gsm->kick_timer, gsm_kick_timer, 0); timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); INIT_WORK(&gsm->tx_work, gsmld_write_task); @@ -2499,9 +2503,6 @@ static int gsm_activate_mux(struct gsm_mux *gsm) if (ret) return ret; - dlci = gsm_dlci_alloc(gsm, 0); - if (dlci == NULL) - return -ENOMEM; gsm->has_devices = true; gsm->dead = false; /* Tty opens are now permissible */ return 0; -- 2.34.1