Incorrect IFUNC use in libpthread for fork, vfork wrapper [BZ #19861]

[Florian Weimer]

On 04/11/2016 11:57 AM, Andreas Schwab wrote:
> Florian Weimer <fweimer@redhat.com> writes:
>
>> I removed it, built a special libdofork.so which has a DT_NEEDED entry for
>> libpthread.so.0 only,
>
> Did you build libdofork before removing the wrapper?

Yes, I did, and I linked explicitly with -lpthread.  After that, I 
patched out the DT_NEEDED entry:

Dynamic segment contains 31 entries:
  Addr: 0x0000000000200db8  Offset: 0x000db8  Link to section: [ 4] 
'.dynstr'
   Type              Value
   NEEDED            Shared library: [libpthread.so.0]
   <unknown>: 0xff   0x000000000000008c

However, the symbol version is stilled mapped to libc.so.6:

Version symbols section [ 5] '.gnu.version' contains 14 entries:
  Addr: 0x000000000000043a  Offset: 0x00043a  Link to section: [ 3] 
'.dynsym'
     0:   0 *local*                        0 *local*
     2:   0 *local*                        0 *local*
     4:   0 *local*                        0 *local*
     6:   2 GLIBC_2.2.5(libc.so.6)         2 GLIBC_2.2.5(libc.so.6)
     8:   1 *global*                       1 *global*
    10:   1 *global*                       1 *global*
    12:   1 *global*                       1 *global*

Version needs section [ 6] '.gnu.version_r' contains 1 entry:
  Addr: 0x0000000000000458  Offset: 0x000458  Link to section: [ 4] 
'.dynstr'
   000000: Version: 1  File: libc.so.6  Cnt: 1
   0x0010: Name: GLIBC_2.2.5  Flags: none  Version: 2

I don't know how t get rid of that.

Florian