linux-kernel - Re: [PATCH 0/2] Regex fixes for mips and x86 cross-compile

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Date:   Thu, 5 Aug 2021 20:54:26 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     "H. Nikolaus Schaller" <hns@...delico.com>
Cc:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        X86 ML <x86@...nel.org>, Jessica Yu <jeyu@...nel.org>,
        Miroslav Benes <mbenes@...e.cz>,
        Emil Velikov <emil.l.velikov@...il.com>,
        Discussions about the Letux Kernel 
        <letux-kernel@...nphoenux.org>, "H. Peter Anvin" <hpa@...or.com>,
        linux-mips <linux-mips@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        kernel@...a-handheld.com,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: Re: [PATCH 0/2] Regex fixes for mips and x86 cross-compile

On Wed, Aug 4, 2021 at 12:59 AM H. Nikolaus Schaller <hns@...delico.com> wrote:
>
> Hi all,
> any chance to get that reviewed and merged into v5.15-rc1 and backported to stable?
> Thank you,
> Nikolaus Schaller



I have a macbook (macOS catalina), and was able to
reproduce this issue.

I applied both to kbuild tree.
Thanks.





>
> > Am 19.07.2021 um 22:37 schrieb Nick Desaulniers <ndesaulniers@...gle.com>:
> >
> > + Masahiro, linux-kbuild (EOM)
> >
> > On Mon, Jul 19, 2021 at 12:07 PM H. Nikolaus Schaller <hns@...delico.com> wrote:
> >>
> >> Any chance that it gets merged?
> >>
> >>> Am 08.07.2021 um 10:57 schrieb H. Nikolaus Schaller <hns@...delico.com>:
> >>>
> >>> Trying to run the x86 relocs tool on a BSD based HOSTCC (cross
> >>> compilation environment) leads to errors like
> >>>
> >>> VOFFSET arch/x86/boot/compressed/../voffset.h - due to: vmlinux
> >>> CC      arch/x86/boot/compressed/misc.o - due to: arch/x86/boot/compressed/../voffset.h
> >>> OBJCOPY arch/x86/boot/compressed/vmlinux.bin - due to: vmlinux
> >>> RELOCS  arch/x86/boot/compressed/vmlinux.relocs - due to: vmlinux
> >>> empty (sub)expressionarch/x86/boot/compressed/Makefile:118: recipe for target 'arch/x86/boot/compressed/vmlinux.relocs' failed
> >>> make[3]: *** [arch/x86/boot/compressed/vmlinux.relocs] Error 1
> >>>
> >>> and when cross compiling a MIPS kernel on a BSD based HOSTCC
> >>> we get errors like
> >>>
> >>> SYNC    include/config/auto.conf.cmd - due to: .config
> >>> egrep: empty (sub)expression
> >>> UPD     include/config/kernel.release
> >>> HOSTCC  scripts/dtc/dtc.o - due to target missing
> >>>
> >>> It turns out that relocs.c on x86 uses patterns like
> >>>
> >>>      "something(|_end)"
> >>>
> >>> while MIPS uses egrep with
> >>>
> >>>      (|MINOR_|PATCHLEVEL_)
> >>>
> >>> In both cases it is not valid syntax or gives undefined results
> >>> according to POSIX 9.5.3 ERE Grammar
> >>>
> >>>      https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html
> >>>
> >>> It seems to be silently accepted by the Linux regcmp() or egrep
> >>> implementation while a BSD host complains.
> >>>
> >>> Such patterns can be replaced by a transformation like
> >>>
> >>>      "(|p1|p2)" -> "(p1|p2)?"
> >>>
> >>> Test Linux:
> >>>
> >>> root@...ux:~# echo foo | egrep '^(|foo)$'
> >>> foo
> >>> root@...ux:~# echo fool | egrep '^(foo)?$'
> >>> root@...ux:~# echo fun | egrep '^(|foo)$'
> >>> root@...ux:~# echo f | egrep '^(|foo)$'
> >>> root@...ux:~# echo | egrep '^(|foo)$'
> >>>
> >>> root@...ux:~# echo foo | egrep '^(foo)?$'
> >>> foo
> >>> root@...ux:~# echo fool | egrep '^(foo)?$'
> >>> root@...ux:~# echo fun | egrep '^(foo)?$'
> >>> root@...ux:~# echo f | egrep '^(foo)?$'
> >>> root@...ux:~# echo | egrep '^(foo)?$'
> >>>
> >>> root@...ux:~#
> >>>
> >>> Test BSD:
> >>>
> >>> iMac:master hns$ echo foo | egrep '^(|foo)$'
> >>> egrep: empty (sub)expression
> >>> iMac:master hns$ echo fool | egrep '^(foo)?$'
> >>> egrep: empty (sub)expression
> >>> iMac:master hns$ echo fun | egrep '^(|foo)$'
> >>> egrep: empty (sub)expression
> >>> iMac:master hns$ echo f | egrep '^(|foo)$'
> >>> egrep: empty (sub)expression
> >>> iMac:master hns$ echo | egrep '^(|foo)$'
> >>> egrep: empty (sub)expression
> >>> iMac:master hns$ echo foo | egrep '^(foo)?$'
> >>> foo
> >>> iMac:master hns$ echo fool | egrep '^(foo)?$'
> >>> iMac:master hns$ echo fun | egrep '^(foo)?$'
> >>> iMac:master hns$ echo f | egrep '^(foo)?$'
> >>> iMac:master hns$ echo | egrep '^(foo)?$'
> >>>
> >>> iMac:master hns$
> >>>
> >>>
> >>> H. Nikolaus Schaller (2):
> >>> x86/tools/relocs: Fix non-POSIX regexp
> >>> arch: mips: Fix non-POSIX regexp
> >>>
> >>> arch/mips/Makefile      | 2 +-
> >>> arch/x86/tools/relocs.c | 8 ++++----
> >>> 2 files changed, 5 insertions(+), 5 deletions(-)
> >>>
> >>> --
> >>> 2.31.1
> >>>
> >>
> >
> >
> > --
> > Thanks,
> > ~Nick Desaulniers
>


-- 
Best Regards
Masahiro Yamada