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Message-ID: <133589afbe999347454dfcc46ae782897bf9e3a2.camel@perches.com>
Subject: Re: [PATCH v2] srcu: avoid escaped section names
From:   Joe Perches <joe@perches.com>
To:     sedat.dilek@gmail.com, Nick Desaulniers <ndesaulniers@google.com>
Cc:     "Paul E . McKenney" <paulmck@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Kees Cook <keescook@chromium.org>,
        linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
        Clang-Built-Linux ML <clang-built-linux@googlegroups.com>
Date:   Wed, 30 Sep 2020 11:57:00 -0700
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         <20200929192549.501516-1-ndesaulniers@google.com>
         <CA+icZUVgfnVQ1=zjUGhGKnJAs9g3Q06sWN3ffNdrfZMZLCEkbA@mail.gmail.com>
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On Wed, 2020-09-30 at 18:41 +0200, Sedat Dilek wrote:
> On Tue, Sep 29, 2020 at 9:25 PM 'Nick Desaulniers' via Clang Built
> Linux <clang-built-linux@googlegroups.com> wrote:
> > The stringification operator, `#`, in the preprocessor escapes strings.
> > For example, `# "foo"` becomes `"\"foo\""`.  GCC and Clang differ in how
> > they treat section names that contain \".
> > 
> > The portable solution is to not use a string literal with the
> > preprocessor stringification operator.
> > 
> > Link: https://bugs.llvm.org/show_bug.cgi?id=42950
> > Fixes: commit fe15b50cdeee ("srcu: Allocate per-CPU data for DEFINE_SRCU() in modules")
> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> 
> Puh, remember one year ago an overnight bisecting to catch the root
> cause for "escaped section names".
> 
> The two patches I see - this here and "export.h: fix section name for
> CONFIG_TRIM_UNUSED_KSYMS for Clang" were new cases?
> 
> Do we have a check-script to catch/avoid such cases (Joe Perches?)?

Try the script that removes #S from #define __section(S)

https://lore.kernel.org/lkml/0e582a7f5144a33f465978d97701f9b3dcc377f3.camel@perches.com/