[PATCH] m68k/atari: Avoid VLA use in atari_switches_setup()

[PATCH] m68k/atari: Avoid VLA use in atari_switches_setup()

[Geert Uytterhoeven]

With gcc 7.3.0:

    arch/m68k/atari/config.c: In function ‘atari_switches_setup’:
    arch/m68k/atari/config.c:151:2: warning: ISO C90 forbids variable length array ‘switches’ [-Wvla]
      char switches[strlen(str) + 1];
      ^~~~

Replace the variable size by the maximum kernel command line size (512
bytes), which is an upper limit for all suboptions.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 arch/m68k/atari/config.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/m68k/atari/config.c b/arch/m68k/atari/config.c
index bd96702a1ad09773..4fcc4b1df1c0f2b4 100644
--- a/arch/m68k/atari/config.c
+++ b/arch/m68k/atari/config.c
@@ -148,7 +148,7 @@ int __init atari_parse_bootinfo(const struct bi_record *record)
 /* Parse the Atari-specific switches= option. */
 static int __init atari_switches_setup(char *str)
 {
-	char switches[strlen(str) + 1];
+	char switches[COMMAND_LINE_SIZE];
 	char *p;
 	int ovsc_shift;
 	char *args = switches;
-- 
2.17.1

Re: [PATCH] m68k/atari: Avoid VLA use in atari_switches_setup()

[Arnd Bergmann]

On Mon, Jan 7, 2019 at 10:29 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> With gcc 7.3.0:
>
>     arch/m68k/atari/config.c: In function ‘atari_switches_setup’:
>     arch/m68k/atari/config.c:151:2: warning: ISO C90 forbids variable length array ‘switches’ [-Wvla]
>       char switches[strlen(str) + 1];
>       ^~~~
>
> Replace the variable size by the maximum kernel command line size (512
> bytes), which is an upper limit for all suboptions.
>
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

Seems fine as long as COMMAND_LINE_SIZE never grows a lot. Some
architectures use 1024 or 2048, but m68k currently has 256 (you write
512 here).

     Arnd

Re: [PATCH] m68k/atari: Avoid VLA use in atari_switches_setup()

[Geert Uytterhoeven]

Hi Arnd,

On Tue, Jan 8, 2019 at 2:25 PM Arnd Bergmann <arnd@arndb.de> wrote:
> On Mon, Jan 7, 2019 at 10:29 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > With gcc 7.3.0:
> >
> >     arch/m68k/atari/config.c: In function ‘atari_switches_setup’:
> >     arch/m68k/atari/config.c:151:2: warning: ISO C90 forbids variable length array ‘switches’ [-Wvla]
> >       char switches[strlen(str) + 1];
> >       ^~~~
> >
> > Replace the variable size by the maximum kernel command line size (512
> > bytes), which is an upper limit for all suboptions.
> >
> > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
> Seems fine as long as COMMAND_LINE_SIZE never grows a lot. Some

If that ever happens, it will be caught by -Wframe-larger-than=1024.

> architectures use 1024 or 2048, but m68k currently has 256 (you write
> 512 here).

Thanks for noticing, will fix!

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] m68k/atari: Avoid VLA use in atari_switches_setup()

[Geert Uytterhoeven]

On Tue, Jan 8, 2019 at 2:47 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Tue, Jan 8, 2019 at 2:25 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > On Mon, Jan 7, 2019 at 10:29 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > With gcc 7.3.0:
> > >
> > >     arch/m68k/atari/config.c: In function ‘atari_switches_setup’:
> > >     arch/m68k/atari/config.c:151:2: warning: ISO C90 forbids variable length array ‘switches’ [-Wvla]
> > >       char switches[strlen(str) + 1];
> > >       ^~~~
> > >
> > > Replace the variable size by the maximum kernel command line size (512
> > > bytes), which is an upper limit for all suboptions.
> > >
> > > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> >
> > Seems fine as long as COMMAND_LINE_SIZE never grows a lot. Some
>
> If that ever happens, it will be caught by -Wframe-larger-than=1024.
>
> > architectures use 1024 or 2048, but m68k currently has 256 (you write
> > 512 here).
>
> Thanks for noticing, will fix!

Thanks, fixed, and applied and queued for v5.1.

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