From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756356AbaHYSKc (ORCPT ); Mon, 25 Aug 2014 14:10:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35227 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750938AbaHYSKb (ORCPT ); Mon, 25 Aug 2014 14:10:31 -0400 Date: Mon, 25 Aug 2014 20:08:06 +0200 From: Oleg Nesterov To: Al Viro , Andrew Morton , Linus Torvalds , Suresh Siddha Cc: Bean Anderson , "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable() Message-ID: <20140825180806.GA22193@redhat.com> References: <20140822171142.GA14812@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140822171142.GA14812@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add preempt_disable() + preempt_enable() around math_state_restore() in __restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin() can overwrite fpu->state we are going to restore. Signed-off-by: Oleg Nesterov Cc: stable@vger.kernel.org --- arch/x86/kernel/xsave.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 453343c..c52eb9c 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -397,8 +397,11 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) set_used_math(); } - if (use_eager_fpu()) + if (use_eager_fpu()) { + preempt_disable(); math_state_restore(); + preempt_enable(); + } return err; } else { -- 1.5.5.1