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Re: Commit: PR 22875: Stop strip corrupting unknown relocs


Hi Guys,

>>  Nevertheless it has caused failures with the new test case and the 
>> `mips64-openbsd' and `mips64el-openbsd' targets:

Sorry - I did not not have those targets in my hit-list.  I have now added them.

> diff --git a/bfd/elf64-mips.c b/bfd/elf64-mips.c
> index ea2e921..9501613 100644
> --- a/bfd/elf64-mips.c
> +++ b/bfd/elf64-mips.c
> @@ -3611,7 +3611,7 @@ mips_elf64_rtype_to_howto (bfd *abfd, unsigned int r_type, bfd_boolean rela_p)
>  	  _bfd_error_handler (_("%pB: unsupported relocation type %#x"),
>  			      abfd, r_type);
>  	  bfd_set_error (bfd_error_bad_value);
> -	  r_type = R_MIPS_NONE;
> +	  return NULL;
>  	}
>        if (rela_p)
>  	return &mips_elf64_howto_table_rela[r_type];
> @@ -3800,6 +3800,8 @@ mips_elf64_slurp_one_reloc_table (bfd *abfd, asection *asect,
>  	  relent->addend = rela.r_addend;
>  
>  	  relent->howto = mips_elf64_rtype_to_howto (abfd, type, rela_p);
> +	  if (relent->howto == NULL)
> +	    goto error_return;
>  
>  	  ++relent;
>  	}

I can confirm that this patch fixes the problem for the mips64-openbsd target.
If you want I can check it in.

> 
> An even more strange fact is that mips64el-openbsd creates really odd
> relocs for the strip-13 testcase.  There seems to be a word swap..
> 
> Relocation section '.rela.text' at offset 0x90 contains 2 entries:
>     Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
> 0000000000000000  000000f100000000 R_MIPS_NONE           readelf: Error:  bad symbol index: 000000f1 in reloc
>                     Type2: R_MIPS_NONE      
>                     Type3: R_MIPS_NONE      
> 0000000000000000  0000000000000000 R_MIPS_NONE                               0
>                     Type2: R_MIPS_NONE      
>                     Type3: R_MIPS_NONE      

That is most strange.  The reloc values are being generate by the "dc.a" assembler directive
which is supposed to generate a value that is the size of an address.  (64-bits in this case).
Are mips64el addresses big endian, despite data being little endian ?  That would explain the
discrepancy.


> Oh, and the bad symbol index gets you a segfault on trying to run
> strip -g, at this line
>       if ((*ptr->sym_ptr_ptr)->the_bfd->xvec != abfd->xvec
> in elf64-mip.c:mips_elf64_write_rela.  the_bfd is NULL.

Adding this fixes the problem:

@@ -4112,7 +4114,8 @@ mips_elf64_write_rela (bfd *abfd, asection *sec,
       int_rela.r_addend = ptr->addend;
       int_rela.r_ssym = RSS_UNDEF;
 
-      if ((*ptr->sym_ptr_ptr)->the_bfd->xvec != abfd->xvec
+      if (! bfd_is_const_section ((*ptr->sym_ptr_ptr)->section)
+         && (*ptr->sym_ptr_ptr)->the_bfd->xvec != abfd->xvec
          && ! _bfd_elf_validate_reloc (abfd, ptr))
        {
          *failedp = TRUE;

Cheers
  Nick


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