Re: linux-next: build warnings from the build of Linus' tree

Hi Arnd,

On Fri, 24 Aug 2018 14:46:16 +0200
Arnd Bergmann [off-list ref] wrote:

On Fri, Aug 24, 2018 at 10:23 AM Masami Hiramatsu [off-list ref] wrote:

quoted

On Fri, 24 Aug 2018 13:32:06 +1000
Stephen Rothwell [off-list ref] wrote:

quoted

Hi all,

After merging the origin tree, today's linux-next build (powerpc
allyesconfig) produced these warnings:

Maybe introduced by commit

  6b7dca401cb1 ("tracing: Allow gcov profiling on only ftrace subsystem")

I am guessing, but that is the only new thing that affects all of
kernel/trace ...

Yes, I agree. But I just followed Documentation/dev-tools/gcov.rst
to enable profiling in kernel/trace. Hmm, doesn't ppc64 support
GCOV_PROFILE?  (But as far as I can see, ARCH_HAS_GCOV_PROFILE_ALL
is enabled in arch/powerpc/Kconfig)

Anyway, I'll try to reproduce it.

Thje same commit causes a link failure on ARM with a randconfig
kernel (see https://pastebin.com/KspjpyKG for the .config):

OK, I confirmed that this happened with both gcc-7.3.0 and gcc-8.1.0
with your config.
I also confirmed that CONFIG_GCOV_PROFILE_ALL causes same issue.
(Note that CONFIG_GCOV_PROFILE_ALL depends on !CONFIG_COMPILE_TEST,
 so allyesconfig disables it always)

Hmm, now gcov kernel itself might have a problem on arm and 
powerpc(on gcc-8)?

Thanks,


-- 
Masami Hiramatsu [off-list ref]