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From: "simark at simark dot ca" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug gdb/26876] gdb error: internal-error: Unknown CFA rule when
 debugging the linux kernel with qemu
Date: Sat, 14 Nov 2020 23:38:12 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D26876

--- Comment #7 from Simon Marchi <simark at simark dot ca> ---
(In reply to Tom Tromey from comment #6)
> It looks like find_comp_unit and set_comp_unit have their tests reversed:
>=20
>   bfd *abfd =3D objfile->obfd;
>   if (gdb_bfd_requires_relocations (abfd))
>     return dwarf2_frame_bfd_data.set (abfd, unit);
>   return dwarf2_frame_objfile_data.set (objfile, unit);
>=20
> Seems like it should use the per-BFD when relocations are *not* required.

Oh, interesting!

When I swap that, I no longer get an ASan crash, but I get:

loading vmlinux
scanning for modules in /home/smarchi/build/linux
loading @0xffffffffc011a000: /home/smarchi/build/linux/arch/x86/kvm/kvm-amd=
.ko
Python Exception <class 'gdb.MemoryError'> Cannot access memory at address
0xffff868177dcbff0:=20
Error occurred in Python: Cannot access memory at address 0xffff868177dcbff0

I should be able to fix set_comp_unit/find_comp_unit in the commit that
introduced those changes and bisect again to find when GDB starts giving th=
is
MemoryError...

--=20
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