Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759798Ab0HLKqI (ORCPT ); Thu, 12 Aug 2010 06:46:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3452 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754628Ab0HLKqE (ORCPT ); Thu, 12 Aug 2010 06:46:04 -0400 From: Xiaotian Feng To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Xiaotian Feng , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Brian Gerst , Avi Kivity , Peter Zijlstra Subject: [PATCH] x86: fpu xstate fix memory poison overwritten Date: Thu, 12 Aug 2010 18:45:45 +0800 Message-Id: <1281609945-2861-1-git-send-email-dfeng@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2087 Lines: 50 fpu.state is allocated from task_xstate_cachep, the size of task_xstate_cachep is xstate_size. But fpu.state is an union struct, which size is bigger than xstate_size if cpu_has_xsave, so if we want to visit fpu.state->xsave, the memory we allocated for fpu.state is not enough. This caused many poison/redzone overwritten alerts on task_xstate while using kvm. [ 1899.399373] ============================================================================= [ 1899.399377] BUG task_xstate: Poison overwritten [ 1899.399378] ----------------------------------------------------------------------------- [ 1899.399379] [ 1899.399382] INFO: 0xffff88020aca2100-0xffff88020aca217f. First byte 0x0 instead of 0x6b [ 1899.399385] INFO: Slab 0xffffea000725c300 objects=23 used=12 fp=0xffff88020aca2100 flags=0x200000000040c1 [ 1899.399387] INFO: Object 0xffff88020aca2100 @offset=8448 fp=0xffff88020aca23c0 With this patch applied, the poison overwritten alert disappeared. Signed-off-by: Xiaotian Feng Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Brian Gerst Cc: Avi Kivity Cc: Peter Zijlstra --- arch/x86/kernel/process.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index d401f1d..609bee5 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -59,7 +59,7 @@ void free_thread_info(struct thread_info *ti) void arch_task_cache_init(void) { task_xstate_cachep = - kmem_cache_create("task_xstate", xstate_size, + kmem_cache_create("task_xstate", sizeof(union thread_xstate), __alignof__(union thread_xstate), SLAB_PANIC | SLAB_NOTRACK, NULL); } -- 1.7.2.1 -- 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/