[PATCH v3] ld: Rename a file on Windows fails if target already exists

[Torbjorn SVENSSON]

Hi Jan,

Thanks for the quick reply.

On 2025-07-22 13:52, Jan Beulich wrote:
> On 22.07.2025 11:30, Torbjörn SVENSSON wrote:
>> Changes since v2:
>>
>> - Fixed regression reported by Linaro CI by reversing the
>>    order of bfd_close calls.
> 
> How exactly does the order of bfd_close() calls matter?

I cannot fully answer this question, but doing it in the reverse order (like I did in v2) causes a segmentation fault.
For some reason, the segmentation fault did not happen when I ran the GCC testsuite for arm-none-eabi on Windows, but it does happen when I run ld testsuite for x86_64-linux-gnu on Linux.


Doing it in the v2 order gives me this stacktrace in GDB:

$ gdb -q --args ./ld-new -z norelro -z nomemory-seal  -L/dev/shm/src/binutils-gdb/ld/testsuite/ld-plugin  -r tmpdir/lto-5a.o tmpdir/lto-5b.o --no-error-execstack -o tmpdir/dump tmpdir/dummy.o
Reading symbols from ./ld-new...
(gdb) r
Starting program: /dev/shm/ld/try2/ld/ld-new -z norelro -z nomemory-seal -L/dev/shm/src/binutils-gdb/ld/testsuite/ld-plugin -r tmpdir/lto-5a.o tmpdir/lto-5b.o --no-error-execstack -o tmpdir/dump tmpdir/dummy.o
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00005555555e7951 in bfd_elf64_write_relocs (abfd=0x555555832b70, sec=0x555555835378, data=0x7fffffffd637) at ./bfd.h:952
952       return sec == bfd_abs_section_ptr;
(gdb) bt
#0  0x00005555555e7951 in bfd_elf64_write_relocs (abfd=0x555555832b70, sec=0x555555835378, data=0x7fffffffd637) at ./bfd.h:952
#1  0x00005555555cef27 in bfd_map_over_sections (abfd=abfd@entry=0x555555832b70, operation=0x5555555e7760 <bfd_elf64_write_relocs>, user_storage=user_storage@entry=0x7fffffffd637) at /dev/shm/src/binutils-gdb/bfd/section.c:1387
#2  0x00005555555f435f in _bfd_elf_write_object_contents (abfd=0x555555832b70) at /dev/shm/src/binutils-gdb/bfd/elf.c:7183
#3  0x00005555555cc45e in bfd_close (abfd=abfd@entry=0x555555832b70) at /dev/shm/src/binutils-gdb/bfd/opncls.c:865
#4  0x00005555555a31f2 in cmdline_add_object_only_section (size=912, contents=0x55555581fd90 "\177ELF\002\001\001") at /dev/shm/src/binutils-gdb/ld/ldlang.c:10843
#5  cmdline_emit_object_only_section () at /dev/shm/src/binutils-gdb/ld/ldlang.c:11027
#6  0x000055555558b2e5 in main (argc=<optimized out>, argv=<optimized out>) at /dev/shm/src/binutils-gdb/ld/ldmain.c:1007


Kind regards,
Torbjörn