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 06D55C25B08 for ; Mon, 15 Aug 2022 19:36:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343920AbiHOTfz (ORCPT ); Mon, 15 Aug 2022 15:35:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244222AbiHOT2T (ORCPT ); Mon, 15 Aug 2022 15:28:19 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C384A5D0CF; Mon, 15 Aug 2022 11:43:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 392D7611E7; Mon, 15 Aug 2022 18:43:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B929C433D6; Mon, 15 Aug 2022 18:43:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660589030; bh=DQYpAKgxnwyRGtLDlzQC5Y75d+Ggep7f0vdNwu/fXAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FdUwHOY61+PEYG7wzMlImxL1maXq+mc99hUvGTsgadK3zvuJzKfausZ1r46YSREhY B1gdi9WOJN4ypfg4dYeUxjW4E1EblqzCnI3cavn0xk83ZRu2nuzpaRNSVG8Un44p9t qaagi0Hb8emC2TSU2fGLPSvab2LYivhW6siEehnQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Starke , Sasha Levin Subject: [PATCH 5.15 590/779] tty: n_gsm: fix resource allocation order in gsm_activate_mux() Date: Mon, 15 Aug 2022 20:03:54 +0200 Message-Id: <20220815180402.560197049@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Daniel Starke [ Upstream commit 7349660438603ed19282e75949561406531785a5 ] 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 Link: https://lore.kernel.org/r/20220701122332.2039-2-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/n_gsm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 23fcb34240ac..b5ce10b0656f 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2435,6 +2435,10 @@ 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_waitqueue_head(&gsm->event); @@ -2450,9 +2454,6 @@ 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; -- 2.35.1