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/eep...

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, Jan 03, 2024 at 05:25:11PM +0000, Brian Cain escreveu:
> > From: Mark Wielaard <mark@klomp.org>
> > To: Arnaldo Carvalho de Melo <acme@kernel.org>
> > > llvm-dwarfdump is the only that is managing to process this file on a
> > > fedora:39 system, more work needed to figure out if this is something
> > > elfutils is planning to support, what amount of work would be necessary,
> > > etc.

> > > Mark, do you know about work on elfutils to support:

> > > ⬢[acme@toolbox hexagon-randconfig-r005-20220913-pahole-crash]$ llvm-
> > dwarfdump at24.ko | head -22
> > > at24.ko:        file format elf32-hexagon

> > That seems to identify itself as an EM_QDSP6 (QUALCOMM DSP6) 32bit ELF
> > file. Neither binutils not elfutils seems to know how to resolve
> > EM_QDSP6 specific relocations. Normally that wouldn't be necessary,
> > but sadly kernel modules are still ET_REL files, so eu-readelf/readelf
> > needs relocations resolved to process the DWARF .debug sections.

> > This seems to need Qualcomm to upstream support for this processor
> > type to bintuils and elfutils.
 
> We can take a look at this.  But - please forgive my inexperience here
> -- do the corresponding tools such as llvm-readelf not suffice here?
> Would it be welcome for us to change pahole to support those if it
> doesn't already?

pahole uses the DWARF library that comes with elfutils, so the changes
that were made to the DWARF library used by llvm-readelf would have to
be done to elfutils' DWARF library for pahole to be able to process
these files.

IANAL to say if you can copy code across these these codebases.

- Arnaldo