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 B1561C4332F for ; Wed, 23 Nov 2022 09:15:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237259AbiKWJPD (ORCPT ); Wed, 23 Nov 2022 04:15:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237295AbiKWJOx (ORCPT ); Wed, 23 Nov 2022 04:14:53 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F419410612F for ; Wed, 23 Nov 2022 01:14:51 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id A7AF7B81EF1 for ; Wed, 23 Nov 2022 09:14:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F020EC433D6; Wed, 23 Nov 2022 09:14:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669194889; bh=bMI6dkkkMc5xKkDcdAp1/uN4HZC3fI9uMyPmQYNVCX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SswBo5x6NXMDMiKfEkxGNCIBagIqCpRkBo4hg3ITbFVvWSctlahztX4NRuFxhepxf k4OXuz8+yzhf1BNDCYAs1Os4icQQ+bqWHhnFH3a9Q/iRMHYzFSlBa2oZ8/MpU1Pmfg 3MEtOuMH0dMTDUyMQgybYbtYZ5liMzOcyIoy0CTo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Duoming Zhou , Sasha Levin Subject: [PATCH 5.4 088/156] tty: n_gsm: fix sleep-in-atomic-context bug in gsm_control_send Date: Wed, 23 Nov 2022 09:50:45 +0100 Message-Id: <20221123084601.170731238@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084557.816085212@linuxfoundation.org> References: <20221123084557.816085212@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: stable@vger.kernel.org From: Duoming Zhou [ Upstream commit 7b7dfe4833c70a11cdfa51b38705103bd31eddaa ] The function gsm_dlci_t1() is a timer handler that runs in an atomic context, but it calls "kzalloc(..., GFP_KERNEL)" that may sleep. As a result, the sleep-in-atomic-context bug will happen. The process is shown below: gsm_dlci_t1() gsm_dlci_open() gsm_modem_update() gsm_modem_upd_via_msc() gsm_control_send() kzalloc(sizeof(.., GFP_KERNEL) //may sleep This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to GFP_ATOMIC in order to mitigate the bug. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Duoming Zhou Link: https://lore.kernel.org/r/20221002040709.27849-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 22da64453054..98c67ddf2fd9 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1413,7 +1413,7 @@ static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, unsigned int command, u8 *data, int clen) { struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), - GFP_KERNEL); + GFP_ATOMIC); unsigned long flags; if (ctrl == NULL) return NULL; -- 2.35.1