From patchwork Tue Jun 23 19:52:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 223564 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 AFEF5C433E0 for ; Tue, 23 Jun 2020 20:07:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 869A32078A for ; Tue, 23 Jun 2020 20:07:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592942864; bh=7i/UUvq2ow8wHVnKokk+DClSu8XQ9EKsbnb7G8pQP90=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nCDWpEUX3sRoRnY8CNFMDdiV3Zq+J9JwXTXJZNBhKoTzyvDrC3ADYWLGUlXPHmQOA 5txXcsjZ/9LNqk/9lDPnXs3LHGgN6XM31LZNiyuCV2kjp2M8XmuReIMvPaelI//CpK KZ7hgzWLCAr9Y1n8334SMIwK5mErD/339tjrQdg0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388632AbgFWUHn (ORCPT ); Tue, 23 Jun 2020 16:07:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:48320 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388641AbgFWUHk (ORCPT ); Tue, 23 Jun 2020 16:07:40 -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 44069206C3; Tue, 23 Jun 2020 20:07:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592942859; bh=7i/UUvq2ow8wHVnKokk+DClSu8XQ9EKsbnb7G8pQP90=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d+FdduQXxUvEi8bKuheTvpeHFgGmEcuLsflWaweWrInAbEewGiYRg33frjNg6fnFh SkSwpcFck0RUIbcvq3T9212qychu8RK4v9sHf9/CSrLDKLq/QWeRAeMs/5T9/ZXm5J hF/Cbf+//3klp/2blQt7JALnQdMO7eCpB2GW5dPc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Sasha Levin Subject: [PATCH 5.7 136/477] ALSA: usb-audio: Fix racy list management in output queue Date: Tue, 23 Jun 2020 21:52:13 +0200 Message-Id: <20200623195414.036092773@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195407.572062007@linuxfoundation.org> References: <20200623195407.572062007@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 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 d8dc7cb56d43c..50104f658ed49 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -346,17 +346,17 @@ 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];