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 7C7D0C28CAC for ; Thu, 16 Sep 2021 17:03:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A0026138B for ; Thu, 16 Sep 2021 17:03:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348883AbhIPRDS (ORCPT ); Thu, 16 Sep 2021 13:03:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:55314 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345678AbhIPQ4M (ORCPT ); Thu, 16 Sep 2021 12:56:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 97A8561ABA; Thu, 16 Sep 2021 16:30:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631809843; bh=7g7VFpPQn5V3ZUik6UpjDE8iJY3WAIaFuDLTsNOoHTg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rqiK3myO7jOtHZ+/IYpG6fDddDXeGCbDSCfhM+nLOtAQ6AmIhgGO5cJCwWzwpBpor qeY1ZegtLS02mq+e7X8/s/XNtlGZWrkbws3l0w0SyclKNP9S0qQI8phy2VVy82OIcb 1L0pLgaL46QEeDhsaJFnNgkWKTkCAgHEqvRlSzmI= 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 5.13 303/380] soundwire: intel: fix potential race condition during power down Date: Thu, 16 Sep 2021 18:01:00 +0200 Message-Id: <20210916155814.362850777@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210916155803.966362085@linuxfoundation.org> References: <20210916155803.966362085@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 fd95f94630b1..c03d51ad40bf 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) { @@ -559,18 +561,19 @@ 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. + */ + } } 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