On Wed, Jan 13, 2021 at 10:18 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
>
> On Wed, Jan 13, 2021 at 11:25 PM Caroline Tice <cmtice@xxxxxxxxxx> wrote:
> >
> > On Tue, Jan 12, 2021 at 3:17 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
> >>
> >> Unfortunately, I see with CONFIG_DEBUG_INFO_DWARF5=y and
> >> CONFIG_DEBUG_INFO_BTF=y:
> >>
> >> die__process_inline_expansion: DW_TAG_INVALID (0x48) @ <0x3f0dd5a> not handled!
> >> die__process_function: DW_TAG_INVALID (0x48) @ <0x3f0dd69> not handled!
I can confirm that I see a stream of these warnings when building with
this patch series applied, and those two configs enabled.
rebuilding with `make ... V=1`, it looks like the call to:
+ pahole -J .tmp_vmlinux.btf
is triggering these.
Shall I send a v4 that adds a Kconfig dependency on !DEBUG_INFO_BTF?
Does pahole have a bug tracker?
> >>
> >> In /usr/include/dwarf.h I found:
> >>
> >> 498: DW_OP_lit24 = 0x48, /* Literal 24. *
> >
> >
> > There are multiple dwarf objects with the value 0x48, depending on which section of the dwarf.h file you search:
> >
> > DW_TAG_call_site = 0x48
> > DW_AT_static_link = 0x48
> > DW_OP_lit24 = 0x48.
> >
> > In this case, since the error message was about a DW_TAG, it would be complaining about DW_TAG_call_site, which is new to DWARF v5.
> >
> Example for "DW_TAG_INVALID (0x48)" from my build-log:
>
> die__process_inline_expansion: DW_TAG_INVALID (0x48) @ <0x1f671e7> not handled!
>
> $ llvm-dwarfdump-11 --debug-info=0x1f671e7 vmlinux
> vmlinux: file format elf64-x86-64
>
> .debug_info contents:
>
> 0x01f671e7: DW_TAG_call_site
> DW_AT_call_return_pc (0xffffffff811b16f2)
> DW_AT_call_origin (0x01f67f1d)
>
> Looking for "DW_AT_call_origin (0x01f67f1d)":
>
> $ llvm-dwarfdump-11 --debug-info=0x01f67f1d vmlinux
> vmlinux: file format elf64-x86-64
>
> .debug_info contents:
>
> 0x01f67f1d: DW_TAG_subprogram
> DW_AT_external (true)
> DW_AT_declaration (true)
> DW_AT_linkage_name ("fput")
> DW_AT_name ("fput")
> DW_AT_decl_file
> ("/home/dileks/src/linux-kernel/git/./include/linux/file.h")
> DW_AT_decl_line (16)
> DW_AT_decl_column (0x0d)
That's a neat trick (using --debug-info=offset to print one element
from the stream).
--
Thanks,
~Nick Desaulniers
