From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755043AbbEEQ5d (ORCPT ); Tue, 5 May 2015 12:57:33 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:37367 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760885AbbEEQ2q (ORCPT ); Tue, 5 May 2015 12:28:46 -0400 From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: Andy Lutomirski , Borislav Petkov , Dave Hansen , Fenghua Yu , "H. Peter Anvin" , Linus Torvalds , Oleg Nesterov , Thomas Gleixner Subject: [PATCH 039/208] x86/fpu: Add debug check to kernel_fpu_disable() Date: Tue, 5 May 2015 18:24:19 +0200 Message-Id: <1430843228-13749-40-git-send-email-mingo@kernel.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1430843228-13749-1-git-send-email-mingo@kernel.org> References: <1430843228-13749-1-git-send-email-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We are not supposed to call kernel_fpu_disable() if we have not previously enabled it. Also use kernel_fpu_disable()/enable() in the __kernel_fpu_begin/end() primitives, instead of writing to in_kernel_fpu directly, so that we get the debugging checks. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/kernel/fpu/core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 587e4ab46f59..bcf705751d02 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -17,6 +17,7 @@ static void kernel_fpu_disable(void) static void kernel_fpu_enable(void) { + WARN_ON_ONCE(!this_cpu_read(in_kernel_fpu)); this_cpu_write(in_kernel_fpu, false); } @@ -77,7 +78,7 @@ void __kernel_fpu_begin(void) { struct task_struct *me = current; - this_cpu_write(in_kernel_fpu, true); + kernel_fpu_disable(); if (__thread_has_fpu(me)) { __save_init_fpu(me); @@ -100,7 +101,7 @@ void __kernel_fpu_end(void) stts(); } - this_cpu_write(in_kernel_fpu, false); + kernel_fpu_enable(); } EXPORT_SYMBOL(__kernel_fpu_end); -- 2.1.0