Re: [kbuild-all] Re: WARNING: modpost: vmlinux.o(.text+0x1a8edb8): Section mismatch in reference from the function stop_machine() to the function .init.text:intel_rng_hw_init()

[Nathan Chancellor <nathan@kernel.org>]

On Thu, Feb 25, 2021 at 04:17:21PM +0800, Rong Chen wrote:
> 
> 
> On 2/24/21 10:26 PM, Jürgen Groß wrote:
> > On 24.02.21 15:20, kernel test robot wrote:
> > > tree:
> > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > > master
> > > head:   c03c21ba6f4e95e406a1a7b4c34ef334b977c194
> > > commit: ab234a260b1f625b26cbefa93ca365b0ae66df33 x86/pv: Rework
> > > arch_local_irq_restore() to not use popf
> > > date:   2 weeks ago
> > > config: x86_64-randconfig-a005-20210223 (attached as .config)
> > > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project
> > > f14a14dd2564703db02f80c00db8ae492b594f77)
> > > reproduce (this is a W=1 build):
> > >          wget
> > > https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross
> > > -O ~/bin/make.cross
> > >          chmod +x ~/bin/make.cross
> > >          # install x86_64 cross compiling tool for clang build
> > >          # apt-get install binutils-x86-64-linux-gnu
> > >          # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab234a260b1f625b26cbefa93ca365b0ae66df33
> > >          git remote add linus
> > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > >          git fetch --no-tags linus master
> > >          git checkout ab234a260b1f625b26cbefa93ca365b0ae66df33
> > >          # save the attached .config to linux build tree
> > >          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross
> > > ARCH=x86_64
> > > 
> > > If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > 
> > > All warnings (new ones prefixed by >>, old ones prefixed by <<):
> > > 
> > > > > WARNING: modpost: vmlinux.o(.text+0x1a8edb8): Section
> > > > > mismatch in reference from the function stop_machine() to
> > > > > the function .init.text:intel_rng_hw_init()
> > > The function stop_machine() references
> > > the function __init intel_rng_hw_init().
> > > This is often because stop_machine lacks a __init
> > > annotation or the annotation of intel_rng_hw_init is wrong.
> > 
> > I'd be very interested to know how the identified patch would be able to
> > have this effect.
> 
> Hi Clang Team,
> 
> The problem is found by the latest clang, and I can't reproduce it with
> clang-11,
> could you take a look?
> 
> Best Regards,
> Rong Chen

Hi Rong,

Known issue. LLVM 13 cut over to the new pass manager (NPM) which has
changed some of the inlining heuristics. I would probably recommend
cutting over to the "release/12.x" branch for now, which should be more
up to date but also stable.

Additionally, Arnd sent a fix for this particular warning here:
https://lore.kernel.org/lkml/20210225130153.1956990-1-arnd@kernel.org/

Cheers,
Nathan