Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755560AbaFREW6 (ORCPT ); Wed, 18 Jun 2014 00:22:58 -0400 Received: from mail-ve0-f180.google.com ([209.85.128.180]:47794 "EHLO mail-ve0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752010AbaFREWz (ORCPT ); Wed, 18 Jun 2014 00:22:55 -0400 MIME-Version: 1.0 In-Reply-To: <53A10C21.8070101@zytor.com> References: <5398749B.4090209@zytor.com> <53A10C21.8070101@zytor.com> From: Andy Lutomirski Date: Tue, 17 Jun 2014 21:22:34 -0700 Message-ID: Subject: Re: vdso_install target broken post-3.15 To: "H. Peter Anvin" Cc: Josh Boyer , "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 On Tue, Jun 17, 2014 at 8:48 PM, H. Peter Anvin wrote: > On 06/17/2014 08:45 PM, Andy Lutomirski wrote: >> On Tue, Jun 17, 2014 at 3:54 PM, Andy Lutomirski wrote: >>> Just a heads up: gdb can't debug the vdso on 3.16-rc1. I filed a bug: >>> >>> https://sourceware.org/bugzilla/show_bug.cgi?id=17064 >>> >>> We may need to extend the fake section header hack to all vdso >>> versions and stick the ELF notes in there. >> >> I have a semi-working implementation of a workaround, bit it adds a >> fair amount of extra crud to the image, and it's pushing my >> configuration past a page boundary. I suspect that, if we're willing >> to abuse the ELF format a bit more, I can get the overhead down, >> though. >> >> Are we okay with regressing here until binutils gets fixed? >> > > Probably not... although I guess it depends just how bad it really is. AFAICT the only issue is that gdb will fail to find installed debug info on systems that install it into .build-id, which AFAIK means Fedora and similar users who install kernel RPMs. This won't effect anyone who installs their own kernel, since it never worked correctly for those users anyway. Fortunately, Fedora ought to be able to update its gdb and/or binutils rpm by the time that 3.16 kernel RPMs show up. Josh, is this workable? In my experience, I've never had a sourceware.org bug fixed, but I have had bugzilla.redhat.org bugs fixed. I'm looking at the binutils code, and I'm kind of scared of it. Also, I don't have an FSF copyright assignment on file. I filed this Fedora bug: https://bugzilla.redhat.com/show_bug.cgi?id=1110598 Let's see what happens. Can we give this a little while? I wrote this: https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=x86/vdso_sections but it's bad: I'm not allocating space properly, so it doesn't reliably build. Also, it wastes space, and I'd rather just get rid of this crap. --Andy -- 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/