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 03032C4727C for ; Tue, 29 Sep 2020 12:38:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A652B2075F for ; Tue, 29 Sep 2020 12:38:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601383095; bh=UE/zt5ax6H4v0FXSLXqzggbfZMly0u9H1SyLBDH6LOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eudk17RxrTOJ7x0qaWlIAJYopWmgL3GXLVrLxJ8Q0TRTX4TKvNBEYpWrbUjj7PxR4 Jzi6Xgau3gXLxIH7FAqUVE4HwdFL2X/N4hJ2F8Z+Yo1DrTQsj1gdJcIiQGKve7NBAb Du9aeNUHToeefVZKX8cQVUWYS7fTCEmt/An2/Muk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733237AbgI2MiO (ORCPT ); Tue, 29 Sep 2020 08:38:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:34778 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729226AbgI2LRn (ORCPT ); Tue, 29 Sep 2020 07:17:43 -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 9558F20848; Tue, 29 Sep 2020 11:17:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378263; bh=UE/zt5ax6H4v0FXSLXqzggbfZMly0u9H1SyLBDH6LOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hlrw3xn0tDPTUWOecuaHe6dNJ/MHunJPIF/Z0vtIfGYyNVhCl9x2wBKq7ne13vfSu FwEszoiErh32O5e2+UTv5M2h822ZNrFb9FrrMfw95l37bVHExzKquZK9VzUKEjPTh6 0okxc6mBqn8kF+VVzI4csqrMi4nnrPgt3FKKqAR4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Sasha Levin Subject: [PATCH 4.14 117/166] ALSA: hda: Fix potential race in unsol event handler Date: Tue, 29 Sep 2020 13:00:29 +0200 Message-Id: <20200929105941.030895517@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105935.184737111@linuxfoundation.org> References: <20200929105935.184737111@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 [ 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