[PATCH] objdump: sframe: fix multiple emission of SFrame and DWARF Frame

[Jens Remus]

On 2/5/2026 10:04 AM, Indu Bhagat wrote:
> On 2/4/26 8:08 AM, Jens Remus wrote:
>> On 2/3/2026 11:37 PM, Indu Bhagat via Binutils wrote:
> 
>>> diff --git a/binutils/objdump.c b/binutils/objdump.c
>>
>>> @@ -4983,33 +4979,40 @@ dump_ctf (bfd *abfd ATTRIBUTE_UNUSED, const char *sect_name ATTRIBUTE_UNUSED,
>>>   #endif
>>>     static void
>>> -dump_sframe_section (bfd *abfd, const char *sect_name, bool is_mainfile)
>>> +dump_sframe_section (bfd *abfd, const char *sect_name)
>>>     {
>>>     /* Error checking for user provided SFrame section name, if any.  */
>>> -  if (sect_name)
>>> +  asection *sec = bfd_get_section_by_name (abfd, sect_name);
>>> +  if (sec == NULL)
>>>       {
>>> -      asection *sec = bfd_get_section_by_name (abfd, sect_name);
>>> -      if (sec == NULL)
>>> -    {
>>> -      printf (_("No %s section present\n\n"), sanitize_string (sect_name));
>>> -      return;
>>> -    }
>>> -      /* Starting with Binutils 2.45, SFrame sections have section type
>>> -     SHT_GNU_SFRAME.  For SFrame sections from Binutils 2.44 or earlier,
>>> -     check explcitly for SFrame sections of type SHT_PROGBITS and name
>>> -     ".sframe" to allow them.  */
>>> -      else if (bfd_get_flavour (abfd) != bfd_target_elf_flavour
>>> -           || (elf_section_type (sec) != SHT_GNU_SFRAME
>>> -           && !(elf_section_type (sec) == SHT_PROGBITS
>>> -            && strcmp (sect_name, ".sframe") == 0)))
>>> -    {
>>> -      printf (_("Section %s does not contain SFrame data\n\n"),
>>> -          sanitize_string (sect_name));
>>> -      return;
>>> -    }
>>> +      printf (_("No %s section present\n\n"), sanitize_string (sect_name));
>>> +      return;
>>> +    }
>>> +  /* Starting with Binutils 2.45, SFrame sections have section type
>>> +     SHT_GNU_SFRAME.  For SFrame sections from Binutils 2.44 or earlier,
>>> +     check explcitly for SFrame sections of type SHT_PROGBITS and name
>>> +     ".sframe" to allow them.  */
>>> +  else if (bfd_get_flavour (abfd) != bfd_target_elf_flavour
>>> +       || (elf_section_type (sec) != SHT_GNU_SFRAME
>>> +           && !(elf_section_type (sec) == SHT_PROGBITS
>>> +            && strcmp (sect_name, ".sframe") == 0)))
>>> +    {
>>> +      printf (_("Section %s does not contain SFrame data\n\n"),
>>> +          sanitize_string (sect_name));
>>> +      return;
>>>       }
>>> -  dump_dwarf (abfd, is_mainfile);
>>> +
>>> +  /* Instead of invoking dump_dwarf () here, load the section and invoke the
>>> +     display function directly.  Otherwise, the textual dump may contain
>>> +     duplicate output due to two invocations of dump_dwarf ().  See PR
>>> +     libsframe/33806.  */
>>> +  if (!load_specific_debug_section (sframe, sec, (void*) abfd))
>>> +    return;
>>> +
>>> +  struct dwarf_section *section = &debug_displays[sframe].section;
>>> +  section->name = sect_name;
>>> +  debug_displays[sframe].display (section, abfd);
>>
>> Why not free the loaded section afterwards, as dump_dwarf_section()
>> would have done?
>>
>>    free_debug_section (sframe);

> free_debug_memory () invocation takes care of free'ing the debug section
> data (including sframe).  So free_debug_section (sframe) looks unnecessary.
Thanks!  That was not obvious to me.  Given that dump_dwarf_section()
does it (and you will likely send a v2 anyway) I wonder whether it would
still make sense so that others are not confused as well.

Tracing objdump --sframe passing multiple objects with .sframe as input
and could confirm that free_debug_section() is called after processing
each input.  I was worried, that the section data of all inputs would
accumulate in a single objdump run.  Especially given it is only done for
(is_mainfile), while dump_sframe_section() might be called for
(is_mainfile || process_links).  Can we rule out that the latter may
trigger dump_sframe_section()?

At least I was not able to trick objdump to follow a link to .sframe:

$ cd path-to-binutils-build/ld/tmpdir
$ ../ld-new -o sframe-sample sframe-foo.o sframe-bar.o
$ cp sframe-sample sframe-sample.full
$ ../../binutils/strip-new --strip-debug -R .sframe sframe-sample
$ ../../binutils/objcopy --add-gnu-debuglink=sframe-sample.full sframe-sample
$ ../../binutils/objdump --sframe sframe-sample
No .sframe section present

Regards,
Jens
-- 
Jens Remus
Linux on Z Development (D3303)
jremus@de.ibm.com / jremus@linux.ibm.com

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