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powerpc/interrupt: Put braces around empty body in an 'if' statement

Message ID 20220619031114.92060-1-jrdr.linux@gmail.com (mailing list archive)
State Rejected
Headers show
Series powerpc/interrupt: Put braces around empty body in an 'if' statement | expand

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Commit Message

Souptick Joarder June 19, 2022, 3:11 a.m. UTC 
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);

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(-)

Comments

Randy Dunlap June 19, 2022, 5:42 a.m. UTC | #1 
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?

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();
>
Christophe Leroy June 19, 2022, 6:40 a.m. UTC | #2 
Le 19/06/2022 à 05:11, Souptick Joarder a écrit :
> 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);
> 
> Fix it by adding braces.

There must be no braces for single 'if' statement , see 
https://docs.kernel.org/process/coding-style.html#placing-braces-and-spaces

The problem is likely that CT_WARN_ON() is empty in some CONFIGs.
You have to fix it, for instance by changing it to a "do { } while (0)"

> 
> 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();
> 
> --
> 2.25.1
>
Souptick Joarder June 19, 2022, 6:43 a.m. UTC | #3 
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
diff mbox series

Patch

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();