Extcon build failure in next

Extcon build failure in next

[Tony Lindgren]

Hi Chanwoo,

Looks like current Linux next fails to build with at least
omap2plus_defconfig because of:

ERROR: "extcon_dev_allocate" [drivers/extcon/devres.ko] undefined!
scripts/Makefile.modpost:91: recipe for target '__modpost' failed
make[1]: *** [__modpost] Error 1
Makefile:1163: recipe for target 'modules' failed
make: *** [modules] Error 2
Kernel build failed

Probably extcon_dev_allocate just needs EXPORT_SYMBOL_GPL?

Regards,

Tony

Extcon build failure in next

[Tony Lindgren]

* Tony Lindgren <tony@atomide.com> [160629 22:41]:
> Hi Chanwoo,
> 
> Looks like current Linux next fails to build with at least
> omap2plus_defconfig because of:
> 
> ERROR: "extcon_dev_allocate" [drivers/extcon/devres.ko] undefined!
> scripts/Makefile.modpost:91: recipe for target '__modpost' failed
> make[1]: *** [__modpost] Error 1
> Makefile:1163: recipe for target 'modules' failed
> make: *** [modules] Error 2
> Kernel build failed
> 
> Probably extcon_dev_allocate just needs EXPORT_SYMBOL_GPL?

Also I'm seeing:

drivers/extcon/extcon.c: In function 'extcon_register_notifier':
drivers/extcon/extcon.c:455:6: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (idx >= 0) {
         ^

Regards,

Tony

Extcon build failure in next

[Arnd Bergmann]

On Wednesday, June 29, 2016 10:41:13 PM CEST Tony Lindgren wrote:
> * Tony Lindgren <tony@atomide.com> [160629 22:41]:
> > Hi Chanwoo,
> > 
> > Looks like current Linux next fails to build with at least
> > omap2plus_defconfig because of:
> > 
> > ERROR: "extcon_dev_allocate" [drivers/extcon/devres.ko] undefined!
> > scripts/Makefile.modpost:91: recipe for target '__modpost' failed
> > make[1]: *** [__modpost] Error 1
> > Makefile:1163: recipe for target 'modules' failed
> > make: *** [modules] Error 2
> > Kernel build failed
> > 
> > Probably extcon_dev_allocate just needs EXPORT_SYMBOL_GPL?

I've sent "extcon: link devres into core module" for this

> Also I'm seeing:
> 
> drivers/extcon/extcon.c: In function 'extcon_register_notifier':
> drivers/extcon/extcon.c:455:6: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
>    if (idx >= 0) {
>          ^

I don't see this one. Which compiler version do you use?

	Arnd

Extcon build failure in next

[Tony Lindgren]

* Arnd Bergmann <arnd@arndb.de> [160630 04:38]:
> On Wednesday, June 29, 2016 10:41:13 PM CEST Tony Lindgren wrote:
> > * Tony Lindgren <tony@atomide.com> [160629 22:41]:
> > > Hi Chanwoo,
> > > 
> > > Looks like current Linux next fails to build with at least
> > > omap2plus_defconfig because of:
> > > 
> > > ERROR: "extcon_dev_allocate" [drivers/extcon/devres.ko] undefined!
> > > scripts/Makefile.modpost:91: recipe for target '__modpost' failed
> > > make[1]: *** [__modpost] Error 1
> > > Makefile:1163: recipe for target 'modules' failed
> > > make: *** [modules] Error 2
> > > Kernel build failed
> > > 
> > > Probably extcon_dev_allocate just needs EXPORT_SYMBOL_GPL?
> 
> I've sent "extcon: link devres into core module" for this

OK thanks.

> > Also I'm seeing:
> > 
> > drivers/extcon/extcon.c: In function 'extcon_register_notifier':
> > drivers/extcon/extcon.c:455:6: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
> >    if (idx >= 0) {
> >          ^
> 
> I don't see this one. Which compiler version do you use?

Looks like I'm currently using older arm-none-linux-gnueabi-gcc
(Sourcery CodeBench Lite 2014.05-29) 4.8.3 20140320 (prerelease).
I think the Debian compiler was not working few months ago and
I changed to something I had around.

Looks like the warning does not appear with arm-linux-gnueabihf-gcc
(Debian 6.1.1-3) 6.1.1 20160511.

Regards,

Tony

Extcon build failure in next

[Arnd Bergmann]

On Thursday, June 30, 2016 4:49:12 AM CEST Tony Lindgren wrote:
> > > Also I'm seeing:
> > > 
> > > drivers/extcon/extcon.c: In function 'extcon_register_notifier':
> > > drivers/extcon/extcon.c:455:6: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > >    if (idx >= 0) {
> > >          ^
> > 
> > I don't see this one. Which compiler version do you use?
> 
> Looks like I'm currently using older arm-none-linux-gnueabi-gcc
> (Sourcery CodeBench Lite 2014.05-29) 4.8.3 20140320 (prerelease).
> I think the Debian compiler was not working few months ago and
> I changed to something I had around.
> 
> Looks like the warning does not appear with arm-linux-gnueabihf-gcc
> (Debian 6.1.1-3) 6.1.1 20160511.

You are certainly not the only one using gcc-4.7 or gcc-4.8, but
they are known to produce more false postive -Wmaybe-uninitialized
warnings and 4.9 or higher. I usually send patches for these warnings
when gcc-6 finds them, and I have recently sent patches for all
the warnings I got in allmodconfig with 4.9, but have no plans to
do that for the older compilers.

I wonder whether we should just disable this warning with gcc-4.8
by adding $(call cc-ifversion, -eq, 0408, -Wno-maybe-uninitialized)
to the command line. However, gcc-4.7 does not let you turn off
the warning at all, so the use of that is fairly limited.

	Arnd

Extcon build failure in next

[Tony Lindgren]

* Arnd Bergmann <arnd@arndb.de> [160630 05:05]:
> On Thursday, June 30, 2016 4:49:12 AM CEST Tony Lindgren wrote:
> > > > Also I'm seeing:
> > > > 
> > > > drivers/extcon/extcon.c: In function 'extcon_register_notifier':
> > > > drivers/extcon/extcon.c:455:6: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > > >    if (idx >= 0) {
> > > >          ^
> > > 
> > > I don't see this one. Which compiler version do you use?
> > 
> > Looks like I'm currently using older arm-none-linux-gnueabi-gcc
> > (Sourcery CodeBench Lite 2014.05-29) 4.8.3 20140320 (prerelease).
> > I think the Debian compiler was not working few months ago and
> > I changed to something I had around.
> > 
> > Looks like the warning does not appear with arm-linux-gnueabihf-gcc
> > (Debian 6.1.1-3) 6.1.1 20160511.
> 
> You are certainly not the only one using gcc-4.7 or gcc-4.8, but
> they are known to produce more false postive -Wmaybe-uninitialized
> warnings and 4.9 or higher. I usually send patches for these warnings
> when gcc-6 finds them, and I have recently sent patches for all
> the warnings I got in allmodconfig with 4.9, but have no plans to
> do that for the older compilers.

OK thanks for the information, I'll change back to something newer
here again.

> I wonder whether we should just disable this warning with gcc-4.8
> by adding $(call cc-ifversion, -eq, 0408, -Wno-maybe-uninitialized)
> to the command line. However, gcc-4.7 does not let you turn off
> the warning at all, so the use of that is fairly limited.

That probably disables warnings also for real warnings too then :)

Tony

Extcon build failure in next

[Geert Uytterhoeven]

On Thu, Jun 30, 2016 at 1:37 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Wednesday, June 29, 2016 10:41:13 PM CEST Tony Lindgren wrote:
>> * Tony Lindgren <tony@atomide.com> [160629 22:41]:
>> Also I'm seeing:
>>
>> drivers/extcon/extcon.c: In function 'extcon_register_notifier':
>> drivers/extcon/extcon.c:455:6: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
>>    if (idx >= 0) {
>>          ^
>
> I don't see this one. Which compiler version do you use?

Also seen with m68k-linux-gnu-gcc-4.1 in current mainline (fix claimed
to be applied).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at 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

Extcon build failure in next

[Chanwoo Choi]

Hi Tony,

On 2016? 06? 30? 14:41, Tony Lindgren wrote:
> * Tony Lindgren <tony@atomide.com> [160629 22:41]:
>> Hi Chanwoo,
>>
>> Looks like current Linux next fails to build with at least
>> omap2plus_defconfig because of:
>>
>> ERROR: "extcon_dev_allocate" [drivers/extcon/devres.ko] undefined!
>> scripts/Makefile.modpost:91: recipe for target '__modpost' failed
>> make[1]: *** [__modpost] Error 1
>> Makefile:1163: recipe for target 'modules' failed
>> make: *** [modules] Error 2
>> Kernel build failed
>>
>> Probably extcon_dev_allocate just needs EXPORT_SYMBOL_GPL?
> 
> Also I'm seeing:
> 
> drivers/extcon/extcon.c: In function 'extcon_register_notifier':
> drivers/extcon/extcon.c:455:6: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
>    if (idx >= 0) {

This issue is already fixed on patch[1] and merged it.
[1] https://git.kernel.org/cgit/linux/kernel/git/chanwoo/extcon.git/commit/?h=extcon-next

Regards,
Chanwoo Choi