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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 9E229C433E0 for ; Thu, 18 Jun 2020 01:27:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C7E221D7A for ; Thu, 18 Jun 2020 01:27:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443629; bh=ZHXm/Zfr+LPZhCMSLNZ/aEVe2ma6TnqweMHKim1xix8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EaCAsSe9ZJDrmE8cNtT/JPUEBKWpFcmrOyOufoQuPdY2B9OwyS+FS7AajZku12N7k EpwHV6HWJE/Ara/XsHhTCdJtpwWT2f+JIJ333DEOwKdQqH7iewjT4ZNAsKNTUaAKaI uJnOuMB84FdiOhf6OzoSDg6qIHbV5MeOXM10MZ8c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731787AbgFRB1I (ORCPT ); Wed, 17 Jun 2020 21:27:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:57632 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730566AbgFRBXp (ORCPT ); Wed, 17 Jun 2020 21:23:45 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 462FE20776; Thu, 18 Jun 2020 01:23:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443424; bh=ZHXm/Zfr+LPZhCMSLNZ/aEVe2ma6TnqweMHKim1xix8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U6mCVmBg51j/xjoLgAG63sAqB6Crdn3GQ//QLvmTTdqCFA6F5/tHwuM+UYSbHmJHk Q7yYnOnlQBv215nnxDm17ZhUWDU9WN0uNNAF7ywyZOEXkMd2Zgt5ecOYmwg7K8Y6Ps UyHV3xsM6E1dgH1z2aR4uKIGhkR9Zv1hsHD0vVXA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takashi Iwai , Sasha Levin , alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 4.19 065/172] ALSA: usb-audio: Fix racy list management in output queue Date: Wed, 17 Jun 2020 21:20:31 -0400 Message-Id: <20200618012218.607130-65-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618012218.607130-1-sashal@kernel.org> References: <20200618012218.607130-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai [ Upstream commit 5b6cc38f3f3f37109ce72b60bda215a5f6892c0b ] The linked list entry from FIFO is peeked at queue_pending_output_urbs() but the actual element pop-out is performed outside the spinlock, and it's potentially racy. Do delete the link at the right place inside the spinlock. Fixes: 8fdff6a319e7 ("ALSA: snd-usb: implement new endpoint streaming model") Link: https://lore.kernel.org/r/20200424074016.14301-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/usb/endpoint.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index 36e255d88937..48611849b79b 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -359,17 +359,17 @@ static void queue_pending_output_urbs(struct snd_usb_endpoint *ep) ep->next_packet_read_pos %= MAX_URBS; /* take URB out of FIFO */ - if (!list_empty(&ep->ready_playback_urbs)) + if (!list_empty(&ep->ready_playback_urbs)) { ctx = list_first_entry(&ep->ready_playback_urbs, struct snd_urb_ctx, ready_list); + list_del_init(&ctx->ready_list); + } } spin_unlock_irqrestore(&ep->lock, flags); if (ctx == NULL) return; - list_del_init(&ctx->ready_list); - /* copy over the length information */ for (i = 0; i < packet->packets; i++) ctx->packet_size[i] = packet->packet_size[i]; -- 2.25.1