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From: "Ozkan Sezer (sezeroz AT gmail DOT com) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
Date: Fri, 22 Jul 2016 15:00:41 +0300
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Subject: Re: LD from binutils 2.26 crashes when -ffunction-sections +
 -Wl,--gc-sections is used but only under DOS
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On 7/22/16, RayeR (glaux AT centrum DOT cz) [via djgpp AT delorie DOT com]
<djgpp AT delorie DOT com> wrote:
>> And if crash it should be consistent and crash under Windows too.
>
> OK, maybe the bug is happening under Windows too but their memory management
> of NTVDM is more benevolent to memory protection and doesn't trigger fault
> in some cases. Even if so the produced binary seems to be OK (and smaller).
>

It segs in fini_reloc_cookie_rels() because (sec)->used_by_bfd is NULL

Program received signal SIGSEGV, Segmentation fault.
0x08088dbd in _bfd_coff_gc_mark (info=0x80f3b80, sec=0x906b248,
gc_mark_hook=0x80859b0 <_bfd_coff_gc_mark_hook>) at
../../binutils-2.26/bfd/coffgen.c:2691
2691	  if (cookie->rels && coff_section_data (NULL, sec)->relocs !=
cookie->rels)
(gdb) bt
#0  0x08088dbd in _bfd_coff_gc_mark (info=0x80f3b80, sec=0x906b248,
gc_mark_hook=0x80859b0 <_bfd_coff_gc_mark_hook>) at
../../binutils-2.26/bfd/coffgen.c:2691
#1  0x08088e22 in _bfd_coff_gc_mark (info=0x80f3b80, sec=0x906b89c,
gc_mark_hook=0x80859b0 <_bfd_coff_gc_mark_hook>) at
../../binutils-2.26/bfd/coffgen.c:2799
#2  0x08088e22 in _bfd_coff_gc_mark (info=0x80f3b80, sec=0x905ac84,
gc_mark_hook=0x80859b0 <_bfd_coff_gc_mark_hook>) at
../../binutils-2.26/bfd/coffgen.c:2799
#3  0x08088e22 in _bfd_coff_gc_mark (info=0x80f3b80, sec=0x905abd0,
gc_mark_hook=0x80859b0 <_bfd_coff_gc_mark_hook>) at
../../binutils-2.26/bfd/coffgen.c:2799
#4  0x08088f31 in bfd_coff_gc_sections (abfd=0x9051918,
info=0x80f3b80) at ../../binutils-2.26/bfd/coffgen.c:3045
#5  0x0805af43 in lang_process () at ../../binutils-2.26/ld/ldlang.c:6502
#6  0x0805e952 in main (argc=15, argv=0xbfb8e504) at
../../binutils-2.26/ld/ldmain.c:414

Doing the following makes the program to run without crashing:

--- binutils-2.26/bfd/coffgen.c.orig
+++ binutils-2.26/bfd/coffgen.c
@@ -2688,8 +2688,11 @@
 fini_reloc_cookie_rels (struct coff_reloc_cookie *cookie,
 			asection *sec)
 {
-  if (cookie->rels && coff_section_data (NULL, sec)->relocs != cookie->rels)
+  if (cookie->rels) {
+   if (!coff_section_data(NULL, sec)) return;
+   if (coff_section_data (NULL, sec)->relocs != cookie->rels)
     free (cookie->rels);
+  }
 }

 /* Initialize the whole of COOKIE for input section SEC.  */

It is very possible that this isn't a proper fix though.

--
O.S.