From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756511AbZJ0Rxt (ORCPT ); Tue, 27 Oct 2009 13:53:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756483AbZJ0Rxt (ORCPT ); Tue, 27 Oct 2009 13:53:49 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:47916 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756480AbZJ0Rxs (ORCPT ); Tue, 27 Oct 2009 13:53:48 -0400 Subject: [PATCH] [GIT PULL] tracing: allow to change permissions for text with dynamic ftrace enabled From: Steven Rostedt Reply-To: rostedt@goodmis.org To: LKML Cc: Ingo Molnar , Suresh Siddha , "H. Peter Anvin" Content-Type: text/plain Organization: Kihon Technologies Inc. Date: Tue, 27 Oct 2009 13:53:43 -0400 Message-Id: <1256666023.26028.411.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo, The cause of the ftrace bug you saw in tip/master was caused by a change in tip's x86/mm branch. Please pull the latest tip/x86/mm tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git tip/x86/mm Steven Rostedt (1): tracing: allow to change permissions for text with dynamic ftrace enabled ---- arch/x86/mm/pageattr.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) --------------------------- commit 883242dd0e5faaba041528a9a99f483f2a656c83 Author: Steven Rostedt Date: Tue Oct 27 13:15:11 2009 -0400 tracing: allow to change permissions for text with dynamic ftrace enabled The commit 74e081797bd9d2a7d8005fe519e719df343a2ba8 x86-64: align RODATA kernel section to 2MB with CONFIG_DEBUG_RODATA prevents text sections from becoming read/write using set_memory_rw. The dynamic ftrace changes all text pages to read/write just before converting the calls to tracing to nops, and vice versa. I orginally just added a flag to allow this transaction when ftrace did the change, but I also found that when the CPA testing was running it would remove the read/write as well, and ftrace does not do the text conversion on boot up, and the CPA changes caused the dynamic tracer to fail on self tests. The current solution I have is to simply not to prevent change_page_attr from setting the RW bit for kernel text pages. Reported-by: Ingo Molnar Cc: Suresh Siddha Cc: H. Peter Anvin Signed-off-by: Steven Rostedt diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index b494fc4..78d3168 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -279,7 +279,8 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, __pa((unsigned long)__end_rodata) >> PAGE_SHIFT)) pgprot_val(forbidden) |= _PAGE_RW; -#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) +#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) && \ + !defined(CONFIG_DYNAMIC_FTRACE) /* * Kernel text mappings for the large page aligned .rodata section * will be read-only. For the kernel identity mappings covering