Re: [PATCH] ld: Check bfd_gc_sections return

On 05.08.2026 12:32, H.J. Lu wrote:
> On Wed, Aug 5, 2026 at 4:59 PM Jan Beulich <[email protected]> wrote:
>>
>> On 05.08.2026 10:50, H.J. Lu wrote:
>>> bfd_gc_sections may return false on invalid input:
>>>
>>> ld: pr34448-bug_18.o: bad reloc symbol index (0xf2000005 >= 0x13) for
>>> offset 0x4 in section `.text.get_tls[get_tls]'
>>>
>>> and set the BFD error to bfd_error_bad_value.  Check bfd_gc_sections
>>> return and report the fatal error if the BFD error is bfd_error_bad_value.
>>
>> And what guarantees that bfd_error_bad_value isn't also set for other kinds
>> of errors, from about anywhere in the library? Does bfd_gc_sections()
>> returning false even reliably set the error indicator? That's far from
> 
> If it isn't the case, it is a bug.
> 
>> obvious when looking at e.g. bfd_elf_gc_sections(), so I can't exclude the
>> possibility of bfd_error_bad_value having been on record before the call,
>> and it simply not getting changed.
> 
> Isn't it a bug?

I don't know, as I don't know enough of the history of libbfd. The value could
be meant to be errno-like, i.e. you may need to clear it at certain points
(especially if there's a mix of functions storing into and not storing into
the field).

Jan