linux-kernel - Re: [PATCH v2] arch: fix broken BuildID for arm64 and riscv

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87fscp2v7k.fsf@igel.home>
Date:   Thu, 05 Jan 2023 10:21:03 +0100
From:   Andreas Schwab <schwab@...ux-m68k.org>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     Nathan Chancellor <nathan@...nel.org>, linux-arch@...r.kernel.org,
        linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ard Biesheuvel <ardb@...nel.org>,
        Thorsten Leemhuis <regressions@...mhuis.info>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, Dennis Gilmore <dennis@...il.us>,
        Albert Ou <aou@...s.berkeley.edu>,
        Arnd Bergmann <arnd@...db.de>,
        Jisheng Zhang <jszhang@...nel.org>,
        Nicolas Schier <nicolas@...sle.eu>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>, llvm@...ts.linux.dev
Subject: Re: [PATCH v2] arch: fix broken BuildID for arm64 and riscv

On Jan 05 2023, Masahiro Yamada wrote:

> I do not understand why 99cb0d917ffa affected this.
>
>
> I submitted a fix to shoot the error message "discarded section .exit.text"
>
> https://lore.kernel.org/all/20230105031306.1455409-1-masahiroy@kernel.org/T/#u
>
> I do not understand the binutils commit either,
> but it might have made something good
> because EXIT_TEXT appears twice, in .exit.text, and /DISCARD/.

I think the issue is that the introdution of a second /DISCARD/
directive early in script changes the order of evaluation of the other
/DISCARD/ directive when binutils < 2.36 is used, so that the missing
RUNTIME_DISCARD_EXIT started to become relevant.  As long as /DISCARD/
only appears last, the effect of EXIT_TEXT inside it is always
overridden by its occurence in the .exit.exit output section directive.
When another /DISCARD/ occurs early (and binutils < 2.36 is used) the
effect of EXIT_TEXT inside the second /DISCARD/ (when merged with the
first) overrides its occurence in the .exit.text directive.  The
binutils commit changed that because the new /DISCARD/ directive no
longer affects the order of evaluation of the rest of the directives.

-- 
Andreas Schwab, schwab@...ux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."