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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 16363C3F2D7 for ; Wed, 4 Mar 2020 11:08:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE12F20705 for ; Wed, 4 Mar 2020 11:08:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729366AbgCDLIC (ORCPT ); Wed, 4 Mar 2020 06:08:02 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:45242 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729286AbgCDLIB (ORCPT ); Wed, 4 Mar 2020 06:08:01 -0500 Received: from 79.184.237.41.ipv4.supernova.orange.pl (79.184.237.41) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.341) id 2bd8be21abd0c5ba; Wed, 4 Mar 2020 12:07:58 +0100 From: "Rafael J. Wysocki" To: madhuparnabhowmik10@gmail.com Cc: pavel@ucw.cz, len.brown@intel.com, gregkh@linuxfoundation.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, joel@joelfernandes.org, frextrite@gmail.com, linux-kernel-mentees@lists.linuxfoundation.org, paulmck@kernel.org Subject: Re: [PATCH 1/2] drivers: base: power: main.c: Use built-in RCU list checking Date: Wed, 04 Mar 2020 12:07:58 +0100 Message-ID: <1643853.WSYDh8IRHD@kreacher> In-Reply-To: <20200303194130.24617-1-madhuparnabhowmik10@gmail.com> References: <20200303194130.24617-1-madhuparnabhowmik10@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Tuesday, March 3, 2020 8:41:30 PM CET madhuparnabhowmik10@gmail.com wrote: > From: Madhuparna Bhowmik > > This patch passes the cond argument to list_for_each_entry_rcu() > to fix the following false-positive lockdep warnings: > (with CONFIG_PROVE_RCU_LIST = y) > > [ 330.302784] ============================= > [ 330.302789] WARNING: suspicious RCU usage > [ 330.302796] 5.6.0-rc1+ #5 Not tainted > [ 330.302801] ----------------------------- > [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in non-reader section!! > > [ 330.303303] ============================= > [ 330.303307] WARNING: suspicious RCU usage > [ 330.303311] 5.6.0-rc1+ #5 Not tainted > [ 330.303315] ----------------------------- > [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in non-reader section!! > > [ 331.934969] ============================= > [ 331.934971] WARNING: suspicious RCU usage > [ 331.934973] 5.6.0-rc1+ #5 Not tainted > [ 331.934975] ----------------------------- > [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in non-reader section!! > > [ 332.467772] WARNING: suspicious RCU usage > [ 332.467775] 5.6.0-rc1+ #5 Not tainted > [ 332.467775] ----------------------------- > [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in non-reader section!! > > Signed-off-by: Madhuparna Bhowmik > --- > drivers/base/power/main.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > index 0e99a760aebd..6d1dee7051eb 100644 > --- a/drivers/base/power/main.c > +++ b/drivers/base/power/main.c > @@ -40,6 +40,10 @@ > > typedef int (*pm_callback_t)(struct device *); > > +#define list_for_each_entry_rcu_locked(pos, head, member) \ > + list_for_each_entry_rcu(pos, head, member, \ > + device_links_read_lock_held()) > + > /* > * The entries in the dpm_list list are in a depth first order, simply > * because children are guaranteed to be discovered after parents, and > @@ -266,7 +270,7 @@ static void dpm_wait_for_suppliers(struct device *dev, bool async) > * callbacks freeing the link objects for the links in the list we're > * walking. > */ > - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) > + list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) > if (READ_ONCE(link->status) != DL_STATE_DORMANT) > dpm_wait(link->supplier, async); > > @@ -323,7 +327,7 @@ static void dpm_wait_for_consumers(struct device *dev, bool async) > * continue instead of trying to continue in parallel with its > * unregistration). > */ > - list_for_each_entry_rcu(link, &dev->links.consumers, s_node) > + list_for_each_entry_rcu_locked(link, &dev->links.consumers, s_node) > if (READ_ONCE(link->status) != DL_STATE_DORMANT) > dpm_wait(link->consumer, async); > > @@ -1235,7 +1239,7 @@ static void dpm_superior_set_must_resume(struct device *dev) > > idx = device_links_read_lock(); > > - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) > + list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) > link->supplier->power.must_resume = true; > > device_links_read_unlock(idx); > @@ -1695,7 +1699,7 @@ static void dpm_clear_superiors_direct_complete(struct device *dev) > > idx = device_links_read_lock(); > > - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) { > + list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) { > spin_lock_irq(&link->supplier->power.lock); > link->supplier->power.direct_complete = false; > spin_unlock_irq(&link->supplier->power.lock); > Applied along with the [2/2] (with updated changelogs) as 5.7 material. Thanks!