From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932259AbcFEW5K (ORCPT ); Sun, 5 Jun 2016 18:57:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:42983 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753115AbcFEVmn (ORCPT ); Sun, 5 Jun 2016 17:42:43 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Maciej W. Rozycki" , linux-mips@linux-mips.org, Ralf Baechle Subject: [PATCH 4.4 18/99] MIPS: ptrace: Fix FP context restoration FCSR regression Date: Sun, 5 Jun 2016 14:40:51 -0700 Message-Id: <20160605213904.885319251@linuxfoundation.org> X-Mailer: git-send-email 2.8.3 In-Reply-To: <20160605213902.974592018@linuxfoundation.org> References: <20160605213902.974592018@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maciej W. Rozycki commit 4249548454f7ba4581aeee26bd83f42b48a14d15 upstream. Fix a floating-point context restoration regression introduced with commit 9b26616c8d9d ("MIPS: Respect the ISA level in FCSR handling") that causes a Floating Point exception and consequently a kernel oops with hard float configurations when one or more FCSR Enable and their corresponding Cause bits are set both at a time via a ptrace(2) call. To do so reinstate Cause bit masking originally introduced with commit b1442d39fac2 ("MIPS: Prevent user from setting FCSR cause bits") to address this exact problem and then inadvertently removed from the PTRACE_SETFPREGS request with the commit referred above. Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13238/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/ptrace.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -176,6 +176,7 @@ int ptrace_setfpregs(struct task_struct } __get_user(value, data + 64); + value &= ~FPU_CSR_ALL_X; fcr31 = child->thread.fpu.fcr31; mask = boot_cpu_data.fpu_msk31; child->thread.fpu.fcr31 = (value & ~mask) | (fcr31 & mask);