From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754060AbaBRXEf (ORCPT ); Tue, 18 Feb 2014 18:04:35 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:51099 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751899AbaBRWrB (ORCPT ); Tue, 18 Feb 2014 17:47:01 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Meelis Roos , Andrew Morton , Peter Oberparleiter , "H. Peter Anvin" Subject: [PATCH 3.12 27/32] x86, hweight: Fix BUG when booting with CONFIG_GCOV_PROFILE_ALL=y Date: Tue, 18 Feb 2014 14:47:27 -0800 Message-Id: <20140218224500.869606656@linuxfoundation.org> X-Mailer: git-send-email 1.8.5.1.163.gd7aced9 In-Reply-To: <20140218224500.101465031@linuxfoundation.org> References: <20140218224500.101465031@linuxfoundation.org> User-Agent: quilt/0.61-1 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 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Oberparleiter commit 6583327c4dd55acbbf2a6f25e775b28b3abf9a42 upstream. Commit d61931d89b, "x86: Add optimized popcnt variants" introduced compile flag -fcall-saved-rdi for lib/hweight.c. When combined with options -fprofile-arcs and -O2, this flag causes gcc to generate broken constructor code. As a result, a 64 bit x86 kernel compiled with CONFIG_GCOV_PROFILE_ALL=y prints message "gcov: could not create file" and runs into sproadic BUGs during boot. The gcc people indicate that these kinds of problems are endemic when using ad hoc calling conventions. It is therefore best to treat any file compiled with ad hoc calling conventions as an isolated environment and avoid things like profiling or coverage analysis, since those subsystems assume a "normal" calling conventions. This patch avoids the bug by excluding lib/hweight.o from coverage profiling. Reported-by: Meelis Roos Cc: Andrew Morton Signed-off-by: Peter Oberparleiter Link: http://lkml.kernel.org/r/52F3A30C.7050205@linux.vnet.ibm.com Signed-off-by: H. Peter Anvin Signed-off-by: Greg Kroah-Hartman --- lib/Makefile | 1 + 1 file changed, 1 insertion(+) --- a/lib/Makefile +++ b/lib/Makefile @@ -47,6 +47,7 @@ lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o lib-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o +GCOV_PROFILE_hweight.o := n CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS)) obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o