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From:   Souptick Joarder <jrdr.linux@gmail.com>
Date:   Sun, 19 Jun 2022 12:13:47 +0530
Message-ID: <CAFqt6zYZk43k7deHth3RZHgkD48EaN-et38fCtV97b_qKpy7QA@mail.gmail.com>
Subject: Re: [PATCH] powerpc/interrupt: Put braces around empty body in an
 'if' statement
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Nick Piggin <npiggin@gmail.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Thomas Gleixner <tglx@linutronix.de>,
        Mark Rutland <mark.rutland@arm.com>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Kernel test robot <lkp@intel.com>,
        Frederic Weisbecker <frederic@kernel.org>
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On Sun, Jun 19, 2022 at 11:13 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>
>
>
> On 6/18/22 20:11, Souptick Joarder wrote:
> > From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
> >
> > Kernel test robot throws warning ->
> >
> > arch/powerpc/kernel/interrupt.c:
> > In function 'interrupt_exit_kernel_prepare':
> >
> >>> arch/powerpc/kernel/interrupt.c:542:55: warning: suggest
> > braces around empty body in an 'if' statement [-Wempty-body]
> >      542 |                 CT_WARN_ON(ct_state() == CONTEXT_USER);
>
> That must be when CONFIG_CONTEXT_TRACKING_USER is not set/enabled.
> Can you confirm that?

Yes, CONFIG_CONTEXT_TRACKING_USER is not set.
>
> Then the preferable fix would be in <linux/context_tracking.h>:
>
> change
> #define CT_WARN_ON(cond)
>
> to either an empty do-while loop or a static inline function.
>
> (adding Frederic to Cc:)
>
> >
> > Fix it by adding braces.
> >
> > Reported-by: Kernel test robot <lkp@intel.com>
> > Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
> > ---
> >  arch/powerpc/kernel/interrupt.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
> > index 784ea3289c84..b8a918bab48f 100644
> > --- a/arch/powerpc/kernel/interrupt.c
> > +++ b/arch/powerpc/kernel/interrupt.c
> > @@ -538,8 +538,9 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs)
> >        * CT_WARN_ON comes here via program_check_exception,
> >        * so avoid recursion.
> >        */
> > -     if (TRAP(regs) != INTERRUPT_PROGRAM)
> > +     if (TRAP(regs) != INTERRUPT_PROGRAM) {
> >               CT_WARN_ON(ct_state() == CONTEXT_USER);
> > +     }
> >
> >       kuap = kuap_get_and_assert_locked();
> >
>
> --
> ~Randy