Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755607Ab3DXNtg (ORCPT ); Wed, 24 Apr 2013 09:49:36 -0400 Received: from mail-la0-f51.google.com ([209.85.215.51]:60273 "EHLO mail-la0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755196Ab3DXNtf (ORCPT ); Wed, 24 Apr 2013 09:49:35 -0400 MIME-Version: 1.0 In-Reply-To: <5177B061.50107@imgtec.com> References: <201304222326.IJB21395.FOtVJFHFQMOOSL@I-love.SAKURA.ne.jp> <201304232140.FGF73904.QJOFOVtHFFMSOL@I-love.SAKURA.ne.jp> <51772CD3.3040405@zytor.com> <51772EBC.1050600@zytor.com> <5177B061.50107@imgtec.com> Date: Wed, 24 Apr 2013 16:49:33 +0300 Message-ID: Subject: Re: [PATCH] x86_32: Fix module version table mismatch. From: Andy Shevchenko To: James Hogan Cc: "H. Peter Anvin" , Rusty Russell , Tetsuo Handa , Arjan van de Ven , "linux-kernel@vger.kernel.org" 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: 3183 Lines: 88 It works Tested-by: Andy Shevchenko On Wed, Apr 24, 2013 at 1:13 PM, James Hogan wrote: > On 24/04/13 02:00, H. Peter Anvin wrote: >> On 04/23/2013 05:52 PM, H. Peter Anvin wrote: >>> On 04/23/2013 05:40 AM, Tetsuo Handa wrote: >>>> Commit a4b6a77b "module: fix symbol versioning with symbol prefixes" broke >>>> loading of net/ipv6/ipv6.ko built with CONFIG_MODVERSIONS=y for x86_32. >>> >>> This really does seem to be the offending commit, although I'm still >>> confused how the heck that is possible. >>> >> >> OK, now I grok. >> >> The bug is the use of VMLINUX_SYMBOL_STR(%s) which expands at the time >> the output of modpost is compiled. However, VMLINUX_SYMBOL_STR() unlike >> __VMLINUX_SYMBOL_STR() does macro expansion on its argument, which is >> actively wrong here. > > Yes, nasty bug there (sorry!) > >> I think the choice is either to change this to __VMLINUX_SYMBOL_STR() or >> re-introduce CONFIG_SYMBOL_PREFIX (or its equivalent) so that modprobe >> can emit it at compile time > > Using __VMLINUX_SYMBOL_STR looks like the correct solution to me. > >> (assuming there even should *be* a prefix on >> the symbol here, i.e. that the compiler won't add it.) > > [__]VMLINUX_SYMBOL_STR expands to a string (e.g. "_" "memcmp" or just > "memcmp") so the compiler won't touch it. > >> >> Either way -- James, Rusty, this is in your court. > > How does the patch below look? I presume this is preferred over > making VMLINUX_SYMBOL_STR non-argument-expanding? > > Thanks > James > > Subject: [PATCH 1/1] modpost: fix unwanted VMLINUX_SYMBOL_STR expansion > > Commit a4b6a77b77ba4f526392612c2365797fab956014 ("module: fix symbol > versioning with symbol prefixes") broke the MODVERSIONS loading of any > module using memcmp (e.g. ipv6) on x86_32, as it's defined to > __builtin_memcmp which is expanded by VMLINUX_SYMBOL_STR. Use > __VMLINUX_SYMBOL_STR instead which doesn't expand the argument. > > Reported-by: Tetsuo Handa > Signed-off-by: James Hogan > Cc: Rusty Russell > Cc: Andy Shevchenko > Cc: H. Peter Anvin > --- > 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 1f90961..a4be8e1 100644 > --- a/scripts/mod/modpost.c > +++ b/scripts/mod/modpost.c > @@ -1957,7 +1957,7 @@ static int add_versions(struct buffer *b, struct module *mod) > s->name, mod->name); > continue; > } > - buf_printf(b, "\t{ %#8x, VMLINUX_SYMBOL_STR(%s) },\n", > + buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n", > s->crc, s->name); > } > > -- > 1.8.1.2 > -- With Best Regards, Andy Shevchenko -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/