Re: [PATCH v2] srcu: avoid escaped section names

From: "Paul E. McKenney" <paulmck@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: 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>,
	LKML <linux-kernel@vger.kernel.org>,
	rcu@vger.kernel.org,
	clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH v2] srcu: avoid escaped section names
Date: Fri, 2 Oct 2020 13:51:30 -0700	[thread overview]
Message-ID: <20201002205130.GK29330@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <CAKwvOd=nabONrWyYFK7Y06TrKBOyHHfNUiiy69VJQ2NtCpbp5Q@mail.gmail.com>

On Wed, Sep 30, 2020 at 01:55:48PM -0700, Nick Desaulniers wrote:
> On Wed, Sep 30, 2020 at 1:40 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> >
> > On Tue, Sep 29, 2020 at 12:25:49PM -0700, Nick Desaulniers 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>
> >
> > I am guessing that this needs to go up with other patches.  If so:
> >
> > Acked-by: Paul E. McKenney <paulmck@kernel.org>
> >
> > If not, let me know and I will queue it.
> 
> I could have bundled them up as a series.  I think you can pick it up,
> and I'll owe you a beer?

It is queued, thank you!

When does it need to hit mainline?  (Your default is the v5.11 merge
window, that is, the one following the upcoming merge window.)

                                                        Thanx, Paul

> > > ---
> > > Changes V1->V2:
> > > * drop unrelated Kconfig changes accidentally committed in v1.
> > >
> > >  include/linux/srcutree.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
> > > index 9cfcc8a756ae..9de652f4e1bd 100644
> > > --- a/include/linux/srcutree.h
> > > +++ b/include/linux/srcutree.h
> > > @@ -124,7 +124,7 @@ struct srcu_struct {
> > >  # define __DEFINE_SRCU(name, is_static)                                      \
> > >       is_static struct srcu_struct name;                              \
> > >       struct srcu_struct * const __srcu_struct_##name                 \
> > > -             __section("___srcu_struct_ptrs") = &name
> > > +             __section(___srcu_struct_ptrs) = &name
> > >  #else
> > >  # define __DEFINE_SRCU(name, is_static)                                      \
> > >       static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);      \
> > > --
> > > 2.28.0.709.gb0816b6eb0-goog
> > >
> 
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers