From patchwork Fri Jan 8 13:41:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 12006651 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 73683C433E0 for ; Fri, 8 Jan 2021 13:41:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36F96239FF for ; Fri, 8 Jan 2021 13:41:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726220AbhAHNlw (ORCPT ); Fri, 8 Jan 2021 08:41:52 -0500 Received: from muru.com ([72.249.23.125]:41232 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726059AbhAHNlw (ORCPT ); Fri, 8 Jan 2021 08:41:52 -0500 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id 74DA980B4; Fri, 8 Jan 2021 13:41:33 +0000 (UTC) From: Tony Lindgren To: linux-omap@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Daniel Lezcano , "Paul E . McKenney" , Russell King Subject: [PATCH] ARM: OMAP2+: Fix suspcious RCU usage splats for omap_enter_idle_coupled Date: Fri, 8 Jan 2021 15:41:05 +0200 Message-Id: <20210108134105.58543-1-tony@atomide.com> X-Mailer: git-send-email 2.30.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org We get suspcious RCU usage splats with cpuidle in several places in omap_enter_idle_coupled() with the kernel debug options enabled: 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) 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. For the tick_broadcast related calls, ideally we'd just switch over to using CPUIDLE_FLAG_TIMER_STOP for omap_enter_idle_coupled() to have the generic cpuidle code handle the tick_broadcast related calls for us and then just drop the tick_broadcast calls here. But we're currently missing the call in the common cpuidle code for tick_broadcast_enable() that CPU1 hotplug needs as described in earlier commit 50d6b3cf9403 ("ARM: OMAP2+: fix lack of timer interrupts on CPU1 after hotplug"). Cc: Daniel Lezcano Cc: Paul E. McKenney Cc: Russell King Signed-off-by: Tony Lindgren Acked-by: Paul E. McKenney --- arch/arm/mach-omap2/cpuidle44xx.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/arm/mach-omap2/cpuidle44xx.c b/arch/arm/mach-omap2/cpuidle44xx.c --- a/arch/arm/mach-omap2/cpuidle44xx.c +++ b/arch/arm/mach-omap2/cpuidle44xx.c @@ -151,10 +151,10 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, (cx->mpu_logic_state == PWRDM_POWER_OFF); /* Enter broadcast mode for periodic timers */ - tick_broadcast_enable(); + RCU_NONIDLE(tick_broadcast_enable()); /* Enter broadcast mode for one-shot timers */ - tick_broadcast_enter(); + RCU_NONIDLE(tick_broadcast_enter()); /* * Call idle CPU PM enter notifier chain so that @@ -166,7 +166,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, if (dev->cpu == 0) { pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); - omap_set_pwrdm_state(mpu_pd, cx->mpu_state); + RCU_NONIDLE(omap_set_pwrdm_state(mpu_pd, cx->mpu_state)); /* * Call idle CPU cluster PM enter notifier chain @@ -179,7 +179,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, index = 1; cx = state_ptr + index; pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); - omap_set_pwrdm_state(mpu_pd, cx->mpu_state); + RCU_NONIDLE(omap_set_pwrdm_state(mpu_pd, cx->mpu_state)); mpuss_can_lose_context = 0; } } @@ -195,9 +195,9 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, mpuss_can_lose_context) gic_dist_disable(); - 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])); if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) && mpuss_can_lose_context) { @@ -225,7 +225,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, cpu_pm_exit(); cpu_pm_out: - tick_broadcast_exit(); + RCU_NONIDLE(tick_broadcast_exit()); fail: cpuidle_coupled_parallel_barrier(dev, &abort_barrier);