Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752013AbdF3X73 (ORCPT ); Fri, 30 Jun 2017 19:59:29 -0400 Received: from mail-lf0-f67.google.com ([209.85.215.67]:35703 "EHLO mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751680AbdF3X71 (ORCPT ); Fri, 30 Jun 2017 19:59:27 -0400 MIME-Version: 1.0 In-Reply-To: <20170630225822.25349-1-sboyd@codeaurora.org> References: <20170630225822.25349-1-sboyd@codeaurora.org> From: Rob Clark Date: Fri, 30 Jun 2017 19:59:24 -0400 Message-ID: Subject: Re: [PATCH] kbuild: modpost: Warn about references from rodata to __init text To: Stephen Boyd Cc: Masahiro Yamada , Michal Marek , Linux Kernel Mailing List , linux-arm-msm , "linux-arm-kernel@lists.infradead.org" , linux-kbuild@vger.kernel.org, Bjorn Andersson Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2371 Lines: 55 On Fri, Jun 30, 2017 at 6:58 PM, Stephen Boyd wrote: > If we have a structure that's marked const it will be placed > into the .rodata section but it could reference an init section > function. Include the read only data section in the check we have > for read/write data sections referencing init sections so we can > find this class of problems. This exposes quite a few places > where const marked structures are referencing __init functions and > __init data that we were previously ignoring. > > Cc: Rob Clark > Cc: Bjorn Andersson > Signed-off-by: Stephen Boyd > --- > > Making this change leads to quite a few other errors even on the > multi_v7_defconfig for ARM[1]. I still need to do a build of the > allmodconfig to see how many other errors there, but it seems to > be quite a few. I suppose those will need to be fixed before we can > merge this? thanks.. the explosions you get with these mistakes when building drivers as modules in a distro kernel config are quite "fun" to debug.. I'm not quite sure about the rules for whether merging this would count as a regression, but I would argue those drivers are already broken, just no one noticed yet. Similar to when a new gcc gets more clever about detecting bugs. So I wouldn't be against merging this first to force drivers to fix their crap ;-) BR, -R > [1] https://www.irccloud.com/pastebin/zzqfWGQY/ > > scripts/mod/modpost.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c > index 48397feb08fb..4f2be5c6727d 100644 > --- a/scripts/mod/modpost.c > +++ b/scripts/mod/modpost.c > @@ -903,7 +903,7 @@ static void check_section(const char *modname, struct elf_info *elf, > #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS > #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS > > -#define DATA_SECTIONS ".data", ".data.rel" > +#define DATA_SECTIONS ".rodata", ".data", ".data.rel" > #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ > ".kprobes.text", ".cpuidle.text" > #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >