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=-13.5 required=3.0 tests=BAYES_00,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=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 86746C4741F for ; Tue, 29 Sep 2020 12:26:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3709C2083B for ; Tue, 29 Sep 2020 12:26:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601382384; bh=UE/zt5ax6H4v0FXSLXqzggbfZMly0u9H1SyLBDH6LOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=l9trqk7u4ML6vNcbgutxVyH+2B8+VQ+i2HsxsunDznFkJwoOVJ6CYOLnTEPjoxy4B nbnurYQLhSy7yIQlFg2gW5eKU12irdIe5zoavyOKw2bKDNXifMwoqMU4to6+lyo+xC 8C3kzFwPCD5X9UmC76eyRZ9bHQx7sAW9XCK2NEAw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732717AbgI2MZw (ORCPT ); Tue, 29 Sep 2020 08:25:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:50296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729663AbgI2Ldc (ORCPT ); Tue, 29 Sep 2020 07:33:32 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 4698023BDC; Tue, 29 Sep 2020 11:27:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378857; bh=UE/zt5ax6H4v0FXSLXqzggbfZMly0u9H1SyLBDH6LOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zslgsbTErRVz81RVROcl1PZmO4nHbMxnvvy4pjG0iBpbHS9NAfbcSiFZYS6OWrHIt HKyWsuZEaaUpaRSTRjwwK4ieKDiD87SVjeNrL9Y0YeM5gUi9KuWDyQzFhhoYoQST7+ zO5HHTr0v8uTVfELW3nWOqZiOi4B0K7bBmaAKXgk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Sasha Levin Subject: [PATCH 4.19 164/245] ALSA: hda: Fix potential race in unsol event handler Date: Tue, 29 Sep 2020 13:00:15 +0200 Message-Id: <20200929105954.958847559@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105946.978650816@linuxfoundation.org> References: <20200929105946.978650816@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: stable@vger.kernel.org From: Takashi Iwai [ Upstream commit c637fa151259c0f74665fde7cba5b7eac1417ae5 ] The unsol event handling code has a loop retrieving the read/write indices and the arrays without locking while the append to the array may happen concurrently. This may lead to some inconsistency. Although there hasn't been any proof of this bad results, it's still safer to protect the racy accesses. This patch adds the spinlock protection around the unsol handling loop for addressing it. Here we take bus->reg_lock as the writer side snd_hdac_bus_queue_event() is also protected by that lock. Link: https://lore.kernel.org/r/20200516062556.30951-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/hda/hdac_bus.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/hda/hdac_bus.c b/sound/hda/hdac_bus.c index 714a51721a313..ab9236e4c157e 100644 --- a/sound/hda/hdac_bus.c +++ b/sound/hda/hdac_bus.c @@ -155,6 +155,7 @@ static void process_unsol_events(struct work_struct *work) struct hdac_driver *drv; unsigned int rp, caddr, res; + spin_lock_irq(&bus->reg_lock); while (bus->unsol_rp != bus->unsol_wp) { rp = (bus->unsol_rp + 1) % HDA_UNSOL_QUEUE_SIZE; bus->unsol_rp = rp; @@ -166,10 +167,13 @@ static void process_unsol_events(struct work_struct *work) codec = bus->caddr_tbl[caddr & 0x0f]; if (!codec || !codec->dev.driver) continue; + spin_unlock_irq(&bus->reg_lock); drv = drv_to_hdac_driver(codec->dev.driver); if (drv->unsol_event) drv->unsol_event(codec, res); + spin_lock_irq(&bus->reg_lock); } + spin_unlock_irq(&bus->reg_lock); } /** -- 2.25.1