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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 26D13C64E8A for ; Mon, 30 Nov 2020 10:10:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C655C20855 for ; Mon, 30 Nov 2020 10:10:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727998AbgK3KKg (ORCPT ); Mon, 30 Nov 2020 05:10:36 -0500 Received: from foss.arm.com ([217.140.110.172]:51594 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727714AbgK3KKg (ORCPT ); Mon, 30 Nov 2020 05:10:36 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A044930E; Mon, 30 Nov 2020 02:09:50 -0800 (PST) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DB0003F23F; Mon, 30 Nov 2020 02:09:47 -0800 (PST) References: <20201122201904.30940-1-valentin.schneider@arm.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Cc: peterz@infradead.org, rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com, pbonzini@redhat.com, mathieu.desnoyers@efficios.com, linux@rasmusvillemoes.dk, "Rafael J. Wysocki" , Sebastian Andrzej Siewior , Alex Shi , Daniel Lezcano , Vincenzo Frascino Subject: Re: [PATCH] notifier: Make atomic_notifiers use raw_spinlock In-reply-to: <20201122201904.30940-1-valentin.schneider@arm.com> Date: Mon, 30 Nov 2020 10:09:41 +0000 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On 22/11/20 20:19, Valentin Schneider wrote: > Booting a recent PREEMPT_RT kernel (v5.10-rc3-rt7-rebase) on my arm64 Juno > leads to the idle task blocking on an RT sleeping spinlock down some > notifier path: > > [ 1.809101] BUG: scheduling while atomic: swapper/5/0/0x00000002 > [ 1.809116] Modules linked in: > [ 1.809123] Preemption disabled at: > [ 1.809125] secondary_start_kernel (arch/arm64/kernel/smp.c:227) > [ 1.809146] CPU: 5 PID: 0 Comm: swapper/5 Tainted: G W 5.10.0-rc3-rt7 #168 > [ 1.809153] Hardware name: ARM Juno development board (r0) (DT) > [ 1.809158] Call trace: > [ 1.809160] dump_backtrace (arch/arm64/kernel/stacktrace.c:100 (discriminator 1)) > [ 1.809170] show_stack (arch/arm64/kernel/stacktrace.c:198) > [ 1.809178] dump_stack (lib/dump_stack.c:122) > [ 1.809188] __schedule_bug (kernel/sched/core.c:4886) > [ 1.809197] __schedule (./arch/arm64/include/asm/preempt.h:18 kernel/sched/core.c:4913 kernel/sched/core.c:5040) > [ 1.809204] preempt_schedule_lock (kernel/sched/core.c:5365 (discriminator 1)) > [ 1.809210] rt_spin_lock_slowlock_locked (kernel/locking/rtmutex.c:1072) > [ 1.809217] rt_spin_lock_slowlock (kernel/locking/rtmutex.c:1110) > [ 1.809224] rt_spin_lock (./include/linux/rcupdate.h:647 kernel/locking/rtmutex.c:1139) > [ 1.809231] atomic_notifier_call_chain_robust (kernel/notifier.c:71 kernel/notifier.c:118 kernel/notifier.c:186) > [ 1.809240] cpu_pm_enter (kernel/cpu_pm.c:39 kernel/cpu_pm.c:93) > [ 1.809249] psci_enter_idle_state (drivers/cpuidle/cpuidle-psci.c:52 drivers/cpuidle/cpuidle-psci.c:129) > [ 1.809258] cpuidle_enter_state (drivers/cpuidle/cpuidle.c:238) > [ 1.809267] cpuidle_enter (drivers/cpuidle/cpuidle.c:353) > [ 1.809275] do_idle (kernel/sched/idle.c:132 kernel/sched/idle.c:213 kernel/sched/idle.c:273) > [ 1.809282] cpu_startup_entry (kernel/sched/idle.c:368 (discriminator 1)) > [ 1.809288] secondary_start_kernel (arch/arm64/kernel/smp.c:273) > FWIW, still squealing under v5.10-rc5-rt11.