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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Sat, 28 Sep 2019 00:42:28 +0900
Message-ID: <CAK7LNARQZ49jvPOK5Dg3B7Nog7+zHsAn5=1oHH6hz9ZzJ=S+xA@mail.gmail.com>
Subject: Re: [PATCH 7/7] nsdeps: make generated patches independent of locale
To:     Matthias Maennich <maennich@google.com>
Cc:     Jessica Yu <jeyu@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Martijn Coenen <maco@android.com>,
        Will Deacon <will.deacon@arm.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Fri, Sep 27, 2019 at 10:27 PM Matthias Maennich <maennich@google.com> wrote:
>
> On Fri, Sep 27, 2019 at 06:36:03PM +0900, Masahiro Yamada wrote:
> >scripts/nsdeps automatically generates a patch to add MODULE_IMPORT_NS
> >tags, and what is nicer, it sorts the lines alphabetically with the
> >"sort" command. However, the output from the "sort" command depends
> >on locale.
> >
> >Especially when namespaces contain underscores, the result is
> >different depending on the locale.
> >
> >For example, I got this:
> >
> >$ { echo usbcommon; echo usb_common; } | LANG=en_US.UTF-8 sort
> >usbcommon
> >usb_common
> >$ { echo usbcommon; echo usb_common; } | LANG=C sort
> >usb_common
> >usbcommon
> >
> >So, this means people might potentially send different patches.
> >
> >This kind of issue was reported in the past, for example,
> >commit f55f2328bb28 ("kbuild: make sorting initramfs contents
> >independent of locale").
> >
> >Adding "LANG=C" is a conventional way of fixing when a deterministic
> >result is desirable.
> >
> >Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> >---
> >
> > scripts/nsdeps | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> >diff --git a/scripts/nsdeps b/scripts/nsdeps
> >index 964b7fb8c546..3754dac13b31 100644
> >--- a/scripts/nsdeps
> >+++ b/scripts/nsdeps
> >@@ -41,7 +41,7 @@ generate_deps() {
> >               for source_file in $mod_source_files; do
> >                       sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
> >                       offset=$(wc -l ${source_file}.tmp | awk '{print $1;}')
> >-                      cat $source_file | grep MODULE_IMPORT_NS | sort -u >> ${source_file}.tmp
> >+                      cat $source_file | grep MODULE_IMPORT_NS | LANG=C sort -u >> ${source_file}.tmp
>
> I would prefer to have this set throughout the whole runtime of the
> script. Otherwise we likely see a followup patch. So, either as an
> export at the beginning of this file or as part of the command that
> calls this script.


I prefer to keep it close to the locale-dependent code.


If I move it to somewhere else, I need to add a comment like

# make "sort" command deterministic
export LANG=C

Otherwise, people would have no idea why it is needed.


> With this
>
> Reviewed-by: Matthias Maennich <maennich@google.com>
>
> Cheers,
> Matthias
>
> >                       tail -n +$((offset +1)) ${source_file} | grep -v MODULE_IMPORT_NS >> ${source_file}.tmp
> >                       if ! diff -q ${source_file} ${source_file}.tmp; then
> >                               mv ${source_file}.tmp ${source_file}
> >--
> >2.17.1
> >


-- 
Best Regards
Masahiro Yamada