[-next] ERROR: "strchr" [drivers/target/target_core_mod.ko] undefined!

[-next] ERROR: "strchr" [drivers/target/target_core_mod.ko] undefined!

[Geert Uytterhoeven]

Since a few days, linux-next shows:

| ERROR: "strchr" [drivers/target/target_core_mod.ko] undefined!

in m68k allmodconfig builds
(http://kisskb.ellerman.id.au/kisskb/buildresult/3754323/).

I guess this is caused by the following 3 calls to strstr():

drivers/target/target_core_configfs.c:
+       ptr = strstr(page, "1");

+       str = strstr(buf, "_");

+       str2 = strstr(str+1, "_");

Some versions of gcc replace calls to strstr() with single-character
"needle" string parameters by calls to strchr() behind our back.
This causes linking errors if strchr() is defined as an inline function
in <asm/string.h> (e.g. on m68k).

You can prevent this by explicitly calling strchr() instead.

Cfr. commit 59d309f9c8ef0bd01bf93cc0e758f1d810417bdb
("kgdb: Replace strstr() by strchr() for single-character needles).

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
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Re: [-next] ERROR: "strchr" [drivers/target/target_core_mod.ko] undefined!

[James Bottomley]

On Fri, 2011-01-07 at 11:57 +0100, Geert Uytterhoeven wrote:
> Since a few days, linux-next shows:
> 
> | ERROR: "strchr" [drivers/target/target_core_mod.ko] undefined!
> 
> in m68k allmodconfig builds
> (http://kisskb.ellerman.id.au/kisskb/buildresult/3754323/).
> 
> I guess this is caused by the following 3 calls to strstr():
> 
> drivers/target/target_core_configfs.c:
> +       ptr = strstr(page, "1");
> 
> +       str = strstr(buf, "_");
> 
> +       str2 = strstr(str+1, "_");
> 
> Some versions of gcc replace calls to strstr() with single-character
> "needle" string parameters by calls to strchr() behind our back.
> This causes linking errors if strchr() is defined as an inline function
> in <asm/string.h> (e.g. on m68k).
> 
> You can prevent this by explicitly calling strchr() instead.
> 
> Cfr. commit 59d309f9c8ef0bd01bf93cc0e758f1d810417bdb
> ("kgdb: Replace strstr() by strchr() for single-character needles).
> 
> Gr{oetje,eeting}s,

Surely the fix for this is not to inline it in m68k? If gcc is growing
the capability to make these types of transformations, it's not going to
stop at single entry string strstr().

If you want to keep the fast inline, there is a way (which I forget) to
drop an external reference as well, just in case.

James

Re: [-next] ERROR: "strchr" [drivers/target/target_core_mod.ko] undefined!

[Nicholas A. Bellinger]

On Fri, 2011-01-07 at 09:44 -0600, James Bottomley wrote:
> On Fri, 2011-01-07 at 11:57 +0100, Geert Uytterhoeven wrote:
> > Since a few days, linux-next shows:
> > 
> > | ERROR: "strchr" [drivers/target/target_core_mod.ko] undefined!
> > 
> > in m68k allmodconfig builds
> > (http://kisskb.ellerman.id.au/kisskb/buildresult/3754323/).
> > 
> > I guess this is caused by the following 3 calls to strstr():
> > 
> > drivers/target/target_core_configfs.c:
> > +       ptr = strstr(page, "1");
> > 
> > +       str = strstr(buf, "_");
> > 
> > +       str2 = strstr(str+1, "_");
> > 
> > Some versions of gcc replace calls to strstr() with single-character
> > "needle" string parameters by calls to strchr() behind our back.
> > This causes linking errors if strchr() is defined as an inline function
> > in <asm/string.h> (e.g. on m68k).
> > 
> > You can prevent this by explicitly calling strchr() instead.
> > 
> > Cfr. commit 59d309f9c8ef0bd01bf93cc0e758f1d810417bdb
> > ("kgdb: Replace strstr() by strchr() for single-character needles).
> > 
> > Gr{oetje,eeting}s,
> 
> Surely the fix for this is not to inline it in m68k? If gcc is growing
> the capability to make these types of transformations, it's not going to
> stop at single entry string strstr().
> 
> If you want to keep the fast inline, there is a way (which I forget) to
> drop an external reference as well, just in case.
> 

Hi guys,

So I really don't have a strong perference here, but would tend to agree
with James that this should probably be fixed in m68k..  If this is too
much of an pain for you Geert I am happy to make this change.

Thanks!

--nab