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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 350EEC433EF for ; Thu, 16 Sep 2021 16:28:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 182F561351 for ; Thu, 16 Sep 2021 16:28:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242163AbhIPQ3U (ORCPT ); Thu, 16 Sep 2021 12:29:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:59302 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241712AbhIPQUC (ORCPT ); Thu, 16 Sep 2021 12:20:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D769361390; Thu, 16 Sep 2021 16:14:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631808847; bh=GiDCcw8EAI/e3m9h772NNoRn4DlkDc9x34kowoRI6tw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o7OqTCdZBgPgB7bIFDm0B5CDfmOuNcBWcK7zcFKiTZXRy8Y+mb4D37oTtsSl0Ao1m Bkqa6Z+6nqnR1rrOa8DNBGRn9sSa/4mac97T2Vbvu5BtE9r8+TUFEDBiGCGfK+Btit aqZ4B3u3+dnIYgdRe53q1YTPdLE8KplXwuJIvjDI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pierre-Louis Bossart , Ranjani Sridharan , Bard Liao , Vinod Koul , Sasha Levin Subject: [PATCH 5.10 243/306] soundwire: intel: fix potential race condition during power down Date: Thu, 16 Sep 2021 17:59:48 +0200 Message-Id: <20210916155802.349997999@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210916155753.903069397@linuxfoundation.org> References: <20210916155753.903069397@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: Pierre-Louis Bossart [ Upstream commit ea6942dad4b2a7e1735aa0f10f3d0b04b847750f ] The power down sequence sets the link_up flag as false outside of the mutex_lock. This is potentially unsafe. In additional the flow in that sequence can be improved by first testing if the link was powered, setting the link_up flag as false and proceeding with the power down. In case the CPA bits cannot be cleared, we only flag an error since we cannot deal with interrupts any longer. Signed-off-by: Pierre-Louis Bossart Reviewed-by: Ranjani Sridharan Signed-off-by: Bard Liao Link: https://lore.kernel.org/r/20210818024954.16873-2-yung-chuan.liao@linux.intel.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/soundwire/intel.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c index 6a1e862b16c3..dad4326a2a71 100644 --- a/drivers/soundwire/intel.c +++ b/drivers/soundwire/intel.c @@ -537,12 +537,14 @@ static int intel_link_power_down(struct sdw_intel *sdw) mutex_lock(sdw->link_res->shim_lock); - intel_shim_master_ip_to_glue(sdw); - if (!(*shim_mask & BIT(link_id))) dev_err(sdw->cdns.dev, "%s: Unbalanced power-up/down calls\n", __func__); + sdw->cdns.link_up = false; + + intel_shim_master_ip_to_glue(sdw); + *shim_mask &= ~BIT(link_id); if (!*shim_mask) { @@ -559,20 +561,21 @@ static int intel_link_power_down(struct sdw_intel *sdw) link_control &= spa_mask; ret = intel_clear_bit(shim, SDW_SHIM_LCTL, link_control, cpa_mask); + if (ret < 0) { + dev_err(sdw->cdns.dev, "%s: could not power down link\n", __func__); + + /* + * we leave the sdw->cdns.link_up flag as false since we've disabled + * the link at this point and cannot handle interrupts any longer. + */ + } } link_control = intel_readl(shim, SDW_SHIM_LCTL); mutex_unlock(sdw->link_res->shim_lock); - if (ret < 0) { - dev_err(sdw->cdns.dev, "%s: could not power down link\n", __func__); - - return ret; - } - - sdw->cdns.link_up = false; - return 0; + return ret; } static void intel_shim_sync_arm(struct sdw_intel *sdw) -- 2.30.2