From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755717Ab0J0XCe (ORCPT ); Wed, 27 Oct 2010 19:02:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44993 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752599Ab0J0XCc (ORCPT ); Wed, 27 Oct 2010 19:02:32 -0400 X-User-Agent: K-9 Mail for Android References: <2d1b1d5d2b3930e1acb063cefffbcb2faf049854.1288212486.git.jbaron@redhat.com> In-Reply-To: <2d1b1d5d2b3930e1acb063cefffbcb2faf049854.1288212486.git.jbaron@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH 2/2] jump label: disable due to compiler bug From: "H. Peter Anvin" Date: Wed, 27 Oct 2010 15:21:55 -0700 To: Jason Baron , rostedt@goodmis.org, mingo@elte.hu CC: mathieu.desnoyers@polymtl.ca, tglx@linutronix.de, andi@firstfloor.org, roland@redhat.com, rth@redhat.com, masami.hiramatsu.pt@hitachi.com, fweisbec@gmail.com, avi@redhat.com, davem@davemloft.net, vgoyal@redhat.com, sam@ravnborg.org, tony@bakeyournoodle.com, ddaney@caviumnetworks.com, dsd@laptop.org, linux-kernel@vger.kernel.org Message-ID: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Could you detail the bug, please? static_cpu_has() also uses asm goto. "Jason Baron" wrote: >Unfortunately, we found a compiler bug in the implementation of >'asm goto'. The bug can cause the kernel to crash. > >For now, we are disabling jump labels with a big hammer. When the >gcc fix is committed, we will update the kernel with a better check >for either the version number it's fix in, or some detection of >whether gcc has the fix in place. > >Signed-off-by: Jason Baron >--- > include/linux/jump_label.h | 9 +++++++++ > 1 files changed, 9 insertions(+), 0 deletions(-) > >diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h >index b67cb18..954462a 100644 >--- a/include/linux/jump_label.h >+++ b/include/linux/jump_label.h >@@ -1,11 +1,20 @@ > #ifndef _LINUX_JUMP_LABEL_H > #define _LINUX_JUMP_LABEL_H > >+/* >+ * A compiler bug was found in the implementation of 'asm goto'. Thus, >+ * we are disabling it for now pending a better check for compiler >version >+ * that fixes it. >+ */ >+#if 0 >+ > #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_HAVE_ARCH_JUMP_LABEL) > # include > # define HAVE_JUMP_LABEL > #endif > >+#endif >+ > enum jump_label_type { > JUMP_LABEL_ENABLE, > JUMP_LABEL_DISABLE >-- >1.7.1 -- Sent from my mobile phone. Please pardon any lack of formatting.