From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43389 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753883AbcFEVw6 (ORCPT ); Sun, 5 Jun 2016 17:52:58 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Maciej W. Rozycki" , James Hogan , Tejun Heo , linux-mips@linux-mips.org, Ralf Baechle Subject: [PATCH 4.6 026/121] MIPS: VDSO: Build with `-fno-strict-aliasing Date: Sun, 5 Jun 2016 14:42:58 -0700 Message-Id: <20160605214418.508652766@linuxfoundation.org> In-Reply-To: <20160605214417.708509043@linuxfoundation.org> References: <20160605214417.708509043@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maciej W. Rozycki commit 94cc36b84acc29f543b48bc5ed786011b112a666 upstream. Avoid an aliasing issue causing a build error in VDSO: In file included from include/linux/srcu.h:34:0, from include/linux/notifier.h:15, from ./arch/mips/include/asm/uprobes.h:9, from include/linux/uprobes.h:61, from include/linux/mm_types.h:13, from ./arch/mips/include/asm/vdso.h:14, from arch/mips/vdso/vdso.h:27, from arch/mips/vdso/gettimeofday.c:11: include/linux/workqueue.h: In function 'work_static': include/linux/workqueue.h:186:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] return *work_data_bits(work) & WORK_STRUCT_STATIC; ^ cc1: all warnings being treated as errors make[2]: *** [arch/mips/vdso/gettimeofday.o] Error 1 with a CONFIG_DEBUG_OBJECTS_WORK configuration and GCC 5.2.0. Include `-fno-strict-aliasing' along with compiler options used, as required for kernel code, fixing a problem present since the introduction of VDSO with commit ebb5e78cc634 ("MIPS: Initial implementation of a VDSO"). Thanks to Tejun for diagnosing this properly! Signed-off-by: Maciej W. Rozycki Reviewed-by: James Hogan Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Cc: Tejun Heo Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13357/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman --- arch/mips/vdso/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -9,7 +9,8 @@ ccflags-vdso := \ $(filter -march=%,$(KBUILD_CFLAGS)) cflags-vdso := $(ccflags-vdso) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ - -O2 -g -fPIC -fno-common -fno-builtin -G 0 -DDISABLE_BRANCH_PROFILING \ + -O2 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \ + -DDISABLE_BRANCH_PROFILING \ $(call cc-option, -fno-stack-protector) aflags-vdso := $(ccflags-vdso) \ $(filter -I%,$(KBUILD_CFLAGS)) \