From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44612 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727443AbeHWLaf (ORCPT ); Thu, 23 Aug 2018 07:30:35 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Suzuki K Poulose , Zhizhou Zhang , Catalin Marinas , Sasha Levin Subject: [PATCH 4.9 024/130] arm64: make secondary_start_kernel() notrace Date: Thu, 23 Aug 2018 09:52:20 +0200 Message-Id: <20180823074928.878978851@linuxfoundation.org> In-Reply-To: <20180823074927.161454870@linuxfoundation.org> References: <20180823074927.161454870@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhizhou Zhang [ Upstream commit b154886f7892499d0d3054026e19dfb9a731df61 ] We can't call function trace hook before setup percpu offset. When entering secondary_start_kernel(), percpu offset has not been initialized. So this lead hotplug malfunction. Here is the flow to reproduce this bug: echo 0 > /sys/devices/system/cpu/cpu1/online echo function > /sys/kernel/debug/tracing/current_tracer echo 1 > /sys/kernel/debug/tracing/tracing_on echo 1 > /sys/devices/system/cpu/cpu1/online Acked-by: Mark Rutland Tested-by: Suzuki K Poulose Signed-off-by: Zhizhou Zhang Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -205,7 +205,7 @@ int __cpu_up(unsigned int cpu, struct ta * This is the secondary CPU boot entry. We're using this CPUs * idle thread stack, but a set of temporary page tables. */ -asmlinkage void secondary_start_kernel(void) +asmlinkage notrace void secondary_start_kernel(void) { struct mm_struct *mm = &init_mm; unsigned int cpu = smp_processor_id();