Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760333Ab2EJRoy (ORCPT ); Thu, 10 May 2012 13:44:54 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:52779 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760532Ab2EJRep (ORCPT ); Thu, 10 May 2012 13:34:45 -0400 Message-Id: <20120510173134.514349257@linuxfoundation.org> User-Agent: quilt/0.60-19.1 Date: Thu, 10 May 2012 10:31:50 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Colin Cross , Russell King Subject: [ 18/52] ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd In-Reply-To: <20120510173229.GA5678@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2176 Lines: 61 3.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Colin Cross commit fde165b2a29673aabf18ceff14dea1f1cfb0daad upstream. Commit 4e8ee7de227e3ab9a72040b448ad728c5428a042 (ARM: SMP: use idmap_pgd for mapping MMU enable during secondary booting) switched secondary boot to use idmap_pgd, which is initialized during early_initcall, instead of a page table initialized during __cpu_up. This causes idmap_pgd to contain the static mappings but be missing all dynamic mappings. If a console is registered that creates a dynamic mapping, the printk in secondary_start_kernel will trigger a data abort on the missing mapping before the exception handlers have been initialized, leading to a hang. Initial boot is not affected because no consoles have been registered, and resume is usually not affected because the offending console is suspended. Onlining a cpu with hotplug triggers the problem. A workaround is to the printk in secondary_start_kernel until after the page tables have been switched back to init_mm. Signed-off-by: Colin Cross Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- arch/arm/kernel/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -255,8 +255,6 @@ asmlinkage void __cpuinit secondary_star struct mm_struct *mm = &init_mm; unsigned int cpu = smp_processor_id(); - printk("CPU%u: Booted secondary processor\n", cpu); - /* * All kernel threads share the same mm context; grab a * reference and switch to it. @@ -268,6 +266,8 @@ asmlinkage void __cpuinit secondary_star enter_lazy_tlb(mm, current); local_flush_tlb_all(); + printk("CPU%u: Booted secondary processor\n", cpu); + cpu_init(); preempt_disable(); trace_hardirqs_off(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/