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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 F2587C04FF3 for ; Mon, 24 May 2021 15:37:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CECD86157E for ; Mon, 24 May 2021 15:37:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232614AbhEXPit (ORCPT ); Mon, 24 May 2021 11:38:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:50532 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232442AbhEXPe7 (ORCPT ); Mon, 24 May 2021 11:34:59 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6007C613D6; Mon, 24 May 2021 15:32:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621870346; bh=joO3Ie+i6vmfuJPGjsekZplCcaCP4G08dYDWWb+cgMs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fwZGb3rnhPtIL39BPRBYHYDwgNEuQalCLt3QCeW1DDElgr8j2OBBrbY4l3ply7vIL Zu2IBT/TFHYi14IaBSumJds+fMVfcBx4UY1qZn/GBnq7hXVSvaZ37LtM4jy/m/sILl gtcEILBWFsu+YSRL11E0p4qwe6IHH7Tx/Z5QvwFY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hyeonggon Yoo <42.hyeyoo@gmail.com>, Takashi Iwai Subject: [PATCH 4.9 06/36] ALSA: line6: Fix racy initialization of LINE6 MIDI Date: Mon, 24 May 2021 17:24:51 +0200 Message-Id: <20210524152324.370249772@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210524152324.158146731@linuxfoundation.org> References: <20210524152324.158146731@linuxfoundation.org> User-Agent: quilt/0.66 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: Takashi Iwai commit 05ca447630334c323c9e2b788b61133ab75d60d3 upstream. The initialization of MIDI devices that are found on some LINE6 drivers are currently done in a racy way; namely, the MIDI buffer instance is allocated and initialized in each private_init callback while the communication with the interface is already started via line6_init_cap_control() call before that point. This may lead to Oops in line6_data_received() when a spurious event is received, as reported by syzkaller. This patch moves the MIDI initialization to line6_init_cap_control() as well instead of the too-lately-called private_init for avoiding the race. Also this reduces slightly more lines, so it's a win-win change. Reported-by: syzbot+0d2b3feb0a2887862e06@syzkallerlkml..appspotmail.com Link: https://lore.kernel.org/r/000000000000a4be9405c28520de@google.com Link: https://lore.kernel.org/r/20210517132725.GA50495@hyeyoo Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Link: https://lore.kernel.org/r/20210518083939.1927-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/line6/driver.c | 4 ++++ sound/usb/line6/pod.c | 5 ----- sound/usb/line6/variax.c | 6 ------ 3 files changed, 4 insertions(+), 11 deletions(-) --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -687,6 +687,10 @@ static int line6_init_cap_control(struct line6->buffer_message = kmalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL); if (!line6->buffer_message) return -ENOMEM; + + ret = line6_init_midi(line6); + if (ret < 0) + return ret; } else { ret = line6_hwdep_init(line6); if (ret < 0) --- a/sound/usb/line6/pod.c +++ b/sound/usb/line6/pod.c @@ -421,11 +421,6 @@ static int pod_init(struct usb_line6 *li if (err < 0) return err; - /* initialize MIDI subsystem: */ - err = line6_init_midi(line6); - if (err < 0) - return err; - /* initialize PCM subsystem: */ err = line6_init_pcm(line6, &pod_pcm_properties); if (err < 0) --- a/sound/usb/line6/variax.c +++ b/sound/usb/line6/variax.c @@ -217,7 +217,6 @@ static int variax_init(struct usb_line6 const struct usb_device_id *id) { struct usb_line6_variax *variax = (struct usb_line6_variax *) line6; - int err; line6->process_message = line6_variax_process_message; line6->disconnect = line6_variax_disconnect; @@ -233,11 +232,6 @@ static int variax_init(struct usb_line6 if (variax->buffer_activate == NULL) return -ENOMEM; - /* initialize MIDI subsystem: */ - err = line6_init_midi(&variax->line6); - if (err < 0) - return err; - /* initiate startup procedure: */ variax_startup1(variax); return 0;