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Date:   Mon, 14 Aug 2023 08:47:30 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Peter Xu <peterx@redhat.com>, lkp@intel.com
Cc:     llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
        linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        "Huang, Ying" <ying.huang@intel.com>
Subject: Re: Cannot find symbol for section 69: .text.arch_max_swapfile_size.
Message-ID: <20230814154730.GA3072@dev-arch.thelio-3990X>
References: <202308120906.Efohswpa-lkp@intel.com>
 <ZNpKaiweCbf9i5QS@x1n>
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On Mon, Aug 14, 2023 at 11:38:18AM -0400, Peter Xu wrote:
> On Sat, Aug 12, 2023 at 09:11:33AM +0800, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   190bf7b14b0cf3df19c059061be032bd8994a597
> > commit: be45a4902c7caa717fee6b2f671e59b396ed395c mm/swap: cache maximum swapfile size when init swap
> > date:   11 months ago
> > config: mips-randconfig-r014-20230811 (https://download.01.org/0day-ci/archive/20230812/202308120906.Efohswpa-lkp@intel.com/config)
> > compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
> > reproduce: (https://download.01.org/0day-ci/archive/20230812/202308120906.Efohswpa-lkp@intel.com/reproduce)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202308120906.Efohswpa-lkp@intel.com/
> > 
> > All errors (new ones prefixed by >>):
> > 
> > >> Cannot find symbol for section 69: .text.arch_max_swapfile_size.
> >    mm/swapfile.o: failed
> 
> Hmm.. I don't really know what's the issue here, neither can I reproduce
> this locally - the cross build seems to all work with the reproducer and I
> can see mm/swapfile.o correctly generated.

This is https://github.com/ClangBuiltLinux/linux/issues/1830 and
https://github.com/ClangBuiltLinux/linux/issues/981, which is a bug in
recordmcount with regards to section symbols that occurs when building
with clang's integrated assembler. It happens when the there are only
weak symbols in a .text section, which occurs more often with MIPS due
to LD_DEAD_CODE_DATA_ELIMINATION implying -ffunction-sections (i.e., any
__weak symbol will trigger this) and I can see this randconfig setting
it.

Unfortunately, the robot seems to have tripped over this a lot over the
weekend :/ Intel folks, can this type of warning please be added to your
filter for at least MIPS + LD_DEAD_CODE_DATA_ELIMINATION so that people
don't get bothered?

https://lore.kernel.org/202308121810.APAJIBxn-lkp@intel.com/
https://lore.kernel.org/202308121535.otQuZept-lkp@intel.com/
https://lore.kernel.org/202308121810.APAJIBxn-lkp@intel.com/
https://lore.kernel.org/202308121246.0TYkHC1K-lkp@intel.com/
https://lore.kernel.org/202308120553.IRzzfaXL-lkp@intel.com/
https://lore.kernel.org/202308111956.QRc8XJVr-lkp@intel.com/

Cheers,
Nathan