linux-kernel - Re: [PATCH] x86/vdso, arm64/vdso: fix flip/flop vdso build bug

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: <CAK7LNATFRqRMbJb3d4JoMyCdHDQWxmx05wJ2yBXyukcj05Au-g@mail.gmail.com>
Date:   Fri, 12 Jul 2019 15:24:01 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Naohiro Aota <naohiro.aota@....com>
Cc:     Vincenzo Frascino <vincenzo.frascino@....com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        X86 ML <x86@...nel.org>, Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Peter Collingbourne <pcc@...gle.com>
Subject: Re: [PATCH] x86/vdso, arm64/vdso: fix flip/flop vdso build bug

On Fri, Jul 12, 2019 at 2:46 PM Naohiro Aota <naohiro.aota@....com> wrote:
>
> Two consecutive "make" on an already compiled kernel tree will show
> different behavior:
>
> $ make
>   CALL    scripts/checksyscalls.sh
>   CALL    scripts/atomic/check-atomics.sh
>   DESCEND  objtool
>   CHK     include/generated/compile.h
>   VDSOCHK arch/x86/entry/vdso/vdso64.so.dbg
>   VDSOCHK arch/x86/entry/vdso/vdso32.so.dbg
> Kernel: arch/x86/boot/bzImage is ready  (#3)
>   Building modules, stage 2.
>   MODPOST 12 modules
>
> $ make
>   CALL    scripts/checksyscalls.sh
>   CALL    scripts/atomic/check-atomics.sh
>   DESCEND  objtool
>   CHK     include/generated/compile.h
>   VDSO    arch/x86/entry/vdso/vdso64.so.dbg
>   OBJCOPY arch/x86/entry/vdso/vdso64.so
>   VDSO2C  arch/x86/entry/vdso/vdso-image-64.c
>   CC      arch/x86/entry/vdso/vdso-image-64.o
>   VDSO    arch/x86/entry/vdso/vdso32.so.dbg
>   OBJCOPY arch/x86/entry/vdso/vdso32.so
>   VDSO2C  arch/x86/entry/vdso/vdso-image-32.c
>   CC      arch/x86/entry/vdso/vdso-image-32.o
>   AR      arch/x86/entry/vdso/built-in.a
>   AR      arch/x86/entry/built-in.a
>   AR      arch/x86/built-in.a
>   GEN     .version
>   CHK     include/generated/compile.h
>   UPD     include/generated/compile.h
>   CC      init/version.o
>   AR      init/built-in.a
>   LD      vmlinux.o
> <snip>
>
> This is causing "LD vmlinux" once every two times even without any
> modifications. This is the same bug fixed in commit 92a4728608a8
> ("x86/boot: Fix if_changed build flip/flop bug").  We cannot use two
> "if_changed" in one target. Fix this build bug by merging two commands
> into one function.
>
> Signed-off-by: Naohiro Aota <naohiro.aota@....com>


The code looks OK, but you should split this
into two patches, for arm64 and x86,
and then add Fixes: for each of them.



-- 
Best Regards
Masahiro Yamada