From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932563AbbCCX1P (ORCPT ); Tue, 3 Mar 2015 18:27:15 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36762 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932265AbbCCXVe (ORCPT ); Tue, 3 Mar 2015 18:21:34 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, linux-mips@linux-mips.org, "Hemmo Nieminen" , "David Daney" , "Ralf Baechle" , "Aaro Koskinen" Date: Tue, 03 Mar 2015 22:11:28 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 09/24] MIPS: Fix kernel lockup or crash after CPU offline/online In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.68-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Hemmo Nieminen commit c7754e75100ed5e3068ac5085747f2bfc386c8d6 upstream. As printk() invocation can cause e.g. a TLB miss, printk() cannot be called before the exception handlers have been properly initialized. This can happen e.g. when netconsole has been loaded as a kernel module and the TLB table has been cleared when a CPU was offline. Call cpu_report() in start_secondary() only after the exception handlers have been initialized to fix this. Without the patch the kernel will randomly either lockup or crash after a CPU is onlined and the console driver is a module. Signed-off-by: Hemmo Nieminen Signed-off-by: Aaro Koskinen Cc: David Daney Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/8953/ Signed-off-by: Ralf Baechle [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- arch/mips/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -105,10 +105,10 @@ asmlinkage __cpuinit void start_secondar if ((read_c0_tcbind() & TCBIND_CURTC) == 0) #endif /* CONFIG_MIPS_MT_SMTC */ cpu_probe(); - cpu_report(); per_cpu_trap_init(); mips_clockevent_init(); mp_ops->init_secondary(); + cpu_report(); /* * XXX parity protection should be folded in here when it's converted