[PATCH v2] lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS

[PATCH v2] lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS

[Julian Braha]

When LATENCYTOP is enabled and ARCH_WANT_FRAME_POINTERS
is disabled, Kbuild gives the following warning:

WARNING: unmet direct dependencies detected for FRAME_POINTER
  Depends on [n]: DEBUG_KERNEL [=y] && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS [=n] || MCOUNT [=n]
  Selected by [y]:
  - LATENCYTOP [=y] && DEBUG_KERNEL [=y] && STACKTRACE_SUPPORT [=y] && PROC_FS [=y] && !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86

Depending on ARCH_WANT_FRAME_POINTERS causes a
recursive dependency error.
ARCH_WANT_FRAME_POINTERS is to be selected by the architecture,
and is not supposed to be overridden by other config options.

Signed-off-by: Julian Braha <julianbraha@gmail.com>
---
 lib/Kconfig.debug | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2779c29d9981..8d53ed423899 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1665,7 +1665,7 @@ config LATENCYTOP
 	depends on DEBUG_KERNEL
 	depends on STACKTRACE_SUPPORT
 	depends on PROC_FS
-	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
+	select FRAME_POINTER if MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
 	select KALLSYMS
 	select KALLSYMS_ALL
 	select STACKTRACE
-- 
2.25.1

Re: [PATCH v2] lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS

[Geert Uytterhoeven]

Hi Julian,

On Sun, Mar 28, 2021 at 6:14 AM Julian Braha <julianbraha@gmail.com> wrote:
> When LATENCYTOP is enabled and ARCH_WANT_FRAME_POINTERS
> is disabled, Kbuild gives the following warning:
>
> WARNING: unmet direct dependencies detected for FRAME_POINTER
>   Depends on [n]: DEBUG_KERNEL [=y] && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS [=n] || MCOUNT [=n]
>   Selected by [y]:
>   - LATENCYTOP [=y] && DEBUG_KERNEL [=y] && STACKTRACE_SUPPORT [=y] && PROC_FS [=y] && !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
>
> Depending on ARCH_WANT_FRAME_POINTERS causes a
> recursive dependency error.
> ARCH_WANT_FRAME_POINTERS is to be selected by the architecture,
> and is not supposed to be overridden by other config options.
>
> Signed-off-by: Julian Braha <julianbraha@gmail.com>

Thanks for your patch!

> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1665,7 +1665,7 @@ config LATENCYTOP
>         depends on DEBUG_KERNEL
>         depends on STACKTRACE_SUPPORT
>         depends on PROC_FS
> -       select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
> +       select FRAME_POINTER if MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86

s/select/depends on/?

>         select KALLSYMS
>         select KALLSYMS_ALL
>         select STACKTRACE

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2] lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS

[Andreas Schwab]

On Mär 28 2021, Julian Braha wrote:

> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 2779c29d9981..8d53ed423899 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1665,7 +1665,7 @@ config LATENCYTOP
>  	depends on DEBUG_KERNEL
>  	depends on STACKTRACE_SUPPORT
>  	depends on PROC_FS
> -	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
> +	select FRAME_POINTER if MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86

That doesn't look correct.  It reverses the condition without reversing
the result, which means the result is probably the opposite than intended.

The same expression occurs two more times in this file.  Do those need
to be changed as well?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Re: [PATCH v2] lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS

[Julian Braha]

On Sunday, March 28, 2021 5:04:08 AM EDT you wrote:
> On Mär 28 2021, Julian Braha wrote:
> 
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > index 2779c29d9981..8d53ed423899 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -1665,7 +1665,7 @@ config LATENCYTOP
> >  	depends on DEBUG_KERNEL
> >  	depends on STACKTRACE_SUPPORT
> >  	depends on PROC_FS
> > -	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
> > +	select FRAME_POINTER if MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
> 
> That doesn't look correct.  It reverses the condition without reversing
> the result, which means the result is probably the opposite than intended.
> 
> The same expression occurs two more times in this file.  Do those need
> to be changed as well?
> 
> Andreas.
> 
> 

Hi all,

This was a mistake - I'll resubmit the proper patch. 
Also: yes, the other usages of this select expression in this file
will cause more unmet dependency bugs. 
I'll include those in the resubmission as well.

- Julian Braha