Re: [bcachefs:header_cleanup 21/51] /bin/bash: line 1: 19420 Segmentation fault LLVM_OBJCOPY="llvm-objcopy" pahole -J --btf_gen_floats -j --lang_exclude=rust --skip_encoding_btf_inconsistent_proto --btf_gen_optimized --btf_base vmlinux drivers/misc/eeprom/at24.ko

From: Nathan Chancellor <nathan@kernel.org>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	Brian Cain <bcain@quicinc.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Yujie Liu <yujie.liu@intel.com>,
	kernel test robot <lkp@intel.com>,
	llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
	linux-hexagon@vger.kernel.org, dwarves@vger.kernel.org,
	Mark Wielaard <mark@klomp.org>
Subject: Re: [bcachefs:header_cleanup 21/51] /bin/bash: line 1: 19420 Segmentation fault LLVM_OBJCOPY="llvm-objcopy" pahole -J --btf_gen_floats -j --lang_exclude=rust --skip_encoding_btf_inconsistent_proto --btf_gen_optimized --btf_base vmlinux drivers/misc/eeprom/at24.ko
Date: Wed, 3 Jan 2024 16:55:43 -0700	[thread overview]
Message-ID: <20240103235543.GA696229@dev-arch.thelio-3990X> (raw)
In-Reply-To: <f6moe6xstxuj2wrnqftc2w7kx4yrnjyoqnigxprvnv4ymtgre6@6ioujgedt72e>

On Wed, Jan 03, 2024 at 05:03:17PM -0500, Kent Overstreet wrote:
> On Wed, Jan 03, 2024 at 08:20:10AM -0800, Nick Desaulniers wrote:
> > On Tue, Jan 2, 2024 at 9:53 AM Mark Wielaard <mark@klomp.org> wrote:
> > >
> > > This seems to need Qualcomm to upstream support for this processor
> > > type to bintuils and elfutils.
> > 
> > Probably should disable BTF for hexagon until then.
> 
> Do we want to include a patch for that in the header cleanup tree?

This issue is reproducible on mainline so I don't think there needs to
be a patch for this in the header cleanup tree.

As for the patch, I assume it would look something like this?

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4405f81248fb..1b939f5583eb 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -378,6 +378,8 @@ config DEBUG_INFO_BTF
 	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
 	depends on BPF_SYSCALL
 	depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
+	# pahole uses elfutils, which does not have support for Hexagon relocations
+	depends on !HEXAGON
 	help
 	  Generate deduplicated BTF type information from DWARF debug info.
 	  Turning this on expects presence of pahole tool, which will convert
