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=-9.8 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,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 64952C432C0 for ; Tue, 19 Nov 2019 05:50:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E54221850 for ; Tue, 19 Nov 2019 05:50:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574142629; bh=eCG85q6t7YJoJKlRi9ND0119j3qWg7j8OP8APe9k2Zg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lYcSmCr4bO+wLlf7l+3bAJ0CPzbBLGYeDH/jtnVpzc5hw8LD/Z2j/K9oUueclXmM6 Sw38eO+UhI9IMRbrMNdYYYa3Tq9iTq/29WnRCfcvg37T0BirSUym5S0TUDSCziNUcO PKomjx4843PtY1kpPHHW5l6JXBJ89uM7dPEPUQSE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731629AbfKSFu2 (ORCPT ); Tue, 19 Nov 2019 00:50:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:47450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731611AbfKSFuY (ORCPT ); Tue, 19 Nov 2019 00:50:24 -0500 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 4782B21783; Tue, 19 Nov 2019 05:50:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574142624; bh=eCG85q6t7YJoJKlRi9ND0119j3qWg7j8OP8APe9k2Zg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vLCMPMXskpmsffM4DNq/HbWmvPZLoOv8AMtu3EzHTjBvG4ZIIOHciL6e53nqdC9xd EqDarZEiPZc7/geayIrjJbPrcILj2MpjL6Z/cEqDHCMVFurmSWdEcrJkhX9bIC1rzX so7S3NAmVwEaz2p8sOjvvPMQ/M7T63weHwWrW+fs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Niklas Cassel , Viresh Kumar , Sasha Levin Subject: [PATCH 4.14 144/239] OPP: Protect dev_list with opp_table lock Date: Tue, 19 Nov 2019 06:19:04 +0100 Message-Id: <20191119051332.034700923@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191119051255.850204959@linuxfoundation.org> References: <20191119051255.850204959@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Viresh Kumar [ Upstream commit 3d2556992a878a2210d3be498416aee39e0c32aa ] The dev_list needs to be protected with a lock, else we may have simultaneous access (addition/removal) to it and that would be racy. Extend scope of the opp_table lock to protect dev_list as well. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin --- drivers/base/power/opp/core.c | 21 +++++++++++++++++++-- drivers/base/power/opp/cpu.c | 2 ++ drivers/base/power/opp/opp.h | 2 +- 3 files changed, 22 insertions(+), 3 deletions(-) diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c index d5e7e8cc4f221..8100c87691497 100644 --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c @@ -49,9 +49,14 @@ static struct opp_device *_find_opp_dev(const struct device *dev, static struct opp_table *_find_opp_table_unlocked(struct device *dev) { struct opp_table *opp_table; + bool found; list_for_each_entry(opp_table, &opp_tables, node) { - if (_find_opp_dev(dev, opp_table)) { + mutex_lock(&opp_table->lock); + found = !!_find_opp_dev(dev, opp_table); + mutex_unlock(&opp_table->lock); + + if (found) { _get_opp_table_kref(opp_table); return opp_table; @@ -711,6 +716,8 @@ struct opp_device *_add_opp_dev(const struct device *dev, /* Initialize opp-dev */ opp_dev->dev = dev; + + mutex_lock(&opp_table->lock); list_add(&opp_dev->node, &opp_table->dev_list); /* Create debugfs entries for the opp_table */ @@ -718,6 +725,7 @@ struct opp_device *_add_opp_dev(const struct device *dev, if (ret) dev_err(dev, "%s: Failed to register opp debugfs (%d)\n", __func__, ret); + mutex_unlock(&opp_table->lock); return opp_dev; } @@ -736,6 +744,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev) if (!opp_table) return NULL; + mutex_init(&opp_table->lock); INIT_LIST_HEAD(&opp_table->dev_list); opp_dev = _add_opp_dev(dev, opp_table); @@ -757,7 +766,6 @@ static struct opp_table *_allocate_opp_table(struct device *dev) BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head); INIT_LIST_HEAD(&opp_table->opp_list); - mutex_init(&opp_table->lock); kref_init(&opp_table->kref); /* Secure the device table modification */ @@ -799,6 +807,10 @@ static void _opp_table_kref_release(struct kref *kref) if (!IS_ERR(opp_table->clk)) clk_put(opp_table->clk); + /* + * No need to take opp_table->lock here as we are guaranteed that no + * references to the OPP table are taken at this point. + */ opp_dev = list_first_entry(&opp_table->dev_list, struct opp_device, node); @@ -1702,6 +1714,9 @@ void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, { struct dev_pm_opp *opp, *tmp; + /* Protect dev_list */ + mutex_lock(&opp_table->lock); + /* Find if opp_table manages a single device */ if (list_is_singular(&opp_table->dev_list)) { /* Free static OPPs */ @@ -1712,6 +1727,8 @@ void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, } else { _remove_opp_dev(_find_opp_dev(dev, opp_table), opp_table); } + + mutex_unlock(&opp_table->lock); } void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all) diff --git a/drivers/base/power/opp/cpu.c b/drivers/base/power/opp/cpu.c index 2d87bc1adf38b..66e406bd4d628 100644 --- a/drivers/base/power/opp/cpu.c +++ b/drivers/base/power/opp/cpu.c @@ -222,8 +222,10 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) cpumask_clear(cpumask); if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) { + mutex_lock(&opp_table->lock); list_for_each_entry(opp_dev, &opp_table->dev_list, node) cpumask_set_cpu(opp_dev->dev->id, cpumask); + mutex_unlock(&opp_table->lock); } else { cpumask_set_cpu(cpu_dev->id, cpumask); } diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h index 166eef9905995..0a206c6b90868 100644 --- a/drivers/base/power/opp/opp.h +++ b/drivers/base/power/opp/opp.h @@ -124,7 +124,7 @@ enum opp_table_access { * @dev_list: list of devices that share these OPPs * @opp_list: table of opps * @kref: for reference count of the table. - * @lock: mutex protecting the opp_list. + * @lock: mutex protecting the opp_list and dev_list. * @np: struct device_node pointer for opp's DT node. * @clock_latency_ns_max: Max clock latency in nanoseconds. * @shared_opp: OPP is shared between multiple devices. -- 2.20.1