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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 2DFDBC433E0 for ; Tue, 23 Jun 2020 21:03:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F224520702 for ; Tue, 23 Jun 2020 21:03:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592946198; bh=cEZ8sz7+sb3ad7uTTqXR6PsY7tAHH2fLQBrtuQCGpK0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YmvY1E4Mwm3pxhxSN6DTtwfL7ADjKSXstAJ6iUB3U70uX+08oFQK8mBYzKVYFIv9L WIa3J04Lnrc7oLAWKGKh0C+WEwjGpX2vKOkKlbXBBZR40j92C8ed1cJl+/N+02tlsd KxyeeKOvAl33ms+V5cmNw4Ih//29FaouHlwbuAag= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404296AbgFWVDP (ORCPT ); Tue, 23 Jun 2020 17:03:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:34256 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391978AbgFWUio (ORCPT ); Tue, 23 Jun 2020 16:38:44 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E06512085B; Tue, 23 Jun 2020 20:38:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592944724; bh=cEZ8sz7+sb3ad7uTTqXR6PsY7tAHH2fLQBrtuQCGpK0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P31YHzW6qR3Sz9kDfKuBkbgLijQcMIzoAKcx0AqZS9IasA1Gus1GJlk2aS8TxMnzr Zlgx5JdaOdvujKLW60+7M6BGBexmR5Kk8keg28xxBuH8QRnOZDeP0LTFyi5tbJx885 ua54sjnkdN0q5Z6R2oKWHec/YBsIDdow5FLX/cQk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Sasha Levin Subject: [PATCH 4.19 060/206] ALSA: usb-audio: Fix racy list management in output queue Date: Tue, 23 Jun 2020 21:56:28 +0200 Message-Id: <20200623195319.919537541@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195316.864547658@linuxfoundation.org> References: <20200623195316.864547658@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 36e255d889372..48611849b79b6 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