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Re: rebase segfault


On 1/15/2013 12:24 PM, Corinna Vinschen wrote:
On Jan 15 11:36, marco atzeri wrote:
On 1/15/2013 11:07 AM, Corinna Vinschen wrote:
On Jan 15 09:43, marco atzeri wrote:
rebase is segfaulting on two dlls of new package

postgresql-contrib-9.2.2-1

Full packages here
http://matzeri.altervista.org/cygwin-1.7/postgresql/

Just the two dll's here:
http://matzeri.altervista.org/works/rebase/

for i in *.dll; do echo $i ; rebase -O $i ; done

dict_snowball.dll
Segmentation fault (core dumped)

ltree.dll
Segmentation fault (core dumped)

I don't know exactly what's going on here, but there's a common factor: [...] Both DLLs have a section .gnu_deb, whatever that one is good for. Rebase crashes both times when trying to relocate this .gnu_deb section. As you can see, the .gnu_deb section is pretty small, only 28 resp. 20 bytes. What happens is that the relocation information for the .gnu_deb section appears to be too big. In case of dict_snowball.dll, the reloc info covers 44 relocation entries. The segfault occurs as soon as one entry translates into a memory address which is beyond the committed area of the file memory map. [...]

It seems the result of the .dbg creation, that trunks wrongly the sections. [...] for what I can see a dll with debug symbols should have a .gnu_debuglink sections:

Right. Something's scrambled. AFAIK, the .gnu_debuglink is not relocatable, it only contains a path. ".gnu_deb" appears to be a result of using only the fixed 8 bytes of the section name. Yaakov, do you have any idea what's going on here?

it seems that objcopy is considering the


--long-section-names {enable|disable|keep}

as disable (or keeping an incorrect disable)

using in sequence on a stripped ltree.dll

$ objcopy -v --add-gnu-debuglink="ltree.dll.dbg" ltree.dll
$ objcopy -v --long-section-names enable --add-gnu-debuglink="ltree.dll.dbg" ltree.dll


$ objdump -h ltree.dll

ltree.dll: file format pei-i386

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         000088a8  6fc81000  6fc81000  00000400  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE, DATA
  1 .data         00000dc0  6fc8a000  6fc8a000  00008e00  2**5
                  CONTENTS, ALLOC, LOAD, DATA
  2 .bss          000000f8  6fc8b000  6fc8b000  00000000  2**5
                  ALLOC
  3 .edata        00000e3c  6fc8c000  6fc8c000  00009c00  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  4 .idata        000005b8  6fc8d000  6fc8d000  0000ac00  2**2
                  CONTENTS, ALLOC, LOAD, DATA
  5 .reloc        00000adc  6fc8e000  6fc8e000  0000b200  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  6 .gnu_deb      00000014  6fc8f000  6fc8f000  0000be00  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  7 .gnu_debuglink 00000014  6fc90000  6fc90000  0000c000  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA


I consider this a bug of objcopy: "--add-gnu-debuglink" should imply "--long-section-names enable"



Corinna

Regards
MArco


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