From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40160 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753436AbbGQA6w (ORCPT ); Thu, 16 Jul 2015 20:58:52 -0400 Subject: Patch "arm64: Do not attempt to use init_mm in reset_context()" has been added to the 4.0-stable tree To: catalin.marinas@arm.com, gregkh@linuxfoundation.org Cc: , From: Date: Thu, 16 Jul 2015 17:58:51 -0700 Message-ID: <14370947316291@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled arm64: Do not attempt to use init_mm in reset_context() to the 4.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm64-do-not-attempt-to-use-init_mm-in-reset_context.patch and it can be found in the queue-4.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 565630d503ef24e44c252bed55571b3a0d68455f Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Fri, 12 Jun 2015 11:24:41 +0100 Subject: arm64: Do not attempt to use init_mm in reset_context() From: Catalin Marinas commit 565630d503ef24e44c252bed55571b3a0d68455f upstream. After secondary CPU boot or hotplug, the active_mm of the idle thread is &init_mm. The init_mm.pgd (swapper_pg_dir) is only meant for TTBR1_EL1 and must not be set in TTBR0_EL1. Since when active_mm == &init_mm the TTBR0_EL1 is already set to the reserved value, there is no need to perform any context reset. Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/mm/context.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/arch/arm64/mm/context.c +++ b/arch/arm64/mm/context.c @@ -92,6 +92,14 @@ static void reset_context(void *info) unsigned int cpu = smp_processor_id(); struct mm_struct *mm = current->active_mm; + /* + * current->active_mm could be init_mm for the idle thread immediately + * after secondary CPU boot or hotplug. TTBR0_EL1 is already set to + * the reserved value, so no need to reset any context. + */ + if (mm == &init_mm) + return; + smp_rmb(); asid = cpu_last_asid + cpu; Patches currently in stable-queue which might be from catalin.marinas@arm.com are queue-4.0/arm64-do-not-attempt-to-use-init_mm-in-reset_context.patch queue-4.0/mm-kmemleak-allow-safe-memory-scanning-during-kmemleak-disabling.patch queue-4.0/arm64-entry-fix-context-tracking-for-el0_sp_pc.patch queue-4.0/arm64-vdso-work-around-broken-elf-toolchains-in-makefile.patch queue-4.0/mm-kmemleak_alloc_percpu-should-follow-the-gfp-from-per_alloc.patch queue-4.0/arm64-mm-fix-freeing-of-the-wrong-memmap-entries-with-sparsemem_vmemmap.patch