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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 C1B4DC433E0 for ; Fri, 19 Feb 2021 21:15:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CE3C601FA for ; Fri, 19 Feb 2021 21:15:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229808AbhBSVP0 (ORCPT ); Fri, 19 Feb 2021 16:15:26 -0500 Received: from jabberwock.ucw.cz ([46.255.230.98]:49032 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229612AbhBSVPK (ORCPT ); Fri, 19 Feb 2021 16:15:10 -0500 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id EF3331C0BBD; Fri, 19 Feb 2021 22:14:27 +0100 (CET) Date: Fri, 19 Feb 2021 22:14:27 +0100 From: Pavel Machek To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Daniel Lezcano , "Paul E. McKenney" , Russell King , Tony Lindgren , Sasha Levin Subject: Re: [PATCH 5.10 020/104] ARM: OMAP2+: Fix suspcious RCU usage splats for omap_enter_idle_coupled Message-ID: <20210219211427.GA27750@amd> References: <20210215152719.459796636@linuxfoundation.org> <20210215152720.133238537@linuxfoundation.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="x+6KMIRAuhnl3hBn" Content-Disposition: inline In-Reply-To: <20210215152720.133238537@linuxfoundation.org> User-Agent: Mutt/1.5.23 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --x+6KMIRAuhnl3hBn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > [ Upstream commit 06862d789ddde8a99c1e579e934ca17c15a84755 ] >=20 > We get suspcious RCU usage splats with cpuidle in several places in > omap_enter_idle_coupled() with the kernel debug options enabled: >=20 > RCU used illegally from extended quiescent state! > ... > (_raw_spin_lock_irqsave) > (omap_enter_idle_coupled+0x17c/0x2d8) > (omap_enter_idle_coupled) > (cpuidle_enter_state) > (cpuidle_enter_state_coupled) > (cpuidle_enter) >=20 > Let's use RCU_NONIDLE to suppress these splats. Things got changed around > with commit 1098582a0f6c ("sched,idle,rcu: Push rcu_idle deeper into the > idle path") that started triggering these warnings. I just wanted to check... AFAICT RCU_NONIDLE puts some quite heavy instrumentation around each statement; does it makes sense to group the statements into one in cases like this? Best regards, Pavel > @@ -194,9 +194,9 @@ static int omap_enter_idle_coupled(struct cpuidle_dev= ice *dev, > mpuss_can_lose_context) > gic_dist_disable(); > =20 > - clkdm_deny_idle(cpu_clkdm[1]); > - omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON); > - clkdm_allow_idle(cpu_clkdm[1]); > + RCU_NONIDLE(clkdm_deny_idle(cpu_clkdm[1])); > + RCU_NONIDLE(omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON)); > + RCU_NONIDLE(clkdm_allow_idle(cpu_clkdm[1])); > =20 > if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) && > mpuss_can_lose_context) { --=20 http://www.livejournal.com/~pavelmachek --x+6KMIRAuhnl3hBn Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAmAwKjIACgkQMOfwapXb+vIkpgCbBYhegccEuzEXI5im5gPXByE2 I8oAoJt92eg0+xb/8EHynMF9JMUnK2Yp =WeMU -----END PGP SIGNATURE----- --x+6KMIRAuhnl3hBn--