Description of problem:
The strace delivered in the RHEL 6.4, 6.3 (and possibly earlier) releases does not report the return value for the shmat.  It incorrectly returns a "?" (question mark) instead of the address that the segment was attached to.

Version-Release number of selected component (if applicable):
# strace -V
strace -- version 4.5.19

# uname -a
Linux perf82.lab.bos.redhat.com 2.6.32-330.el6.x86_64 #1 SMP Thu Oct 11 15:37:45 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux


How reproducible:
The simple reproducer .c file and command is listed below

Steps to Reproduce:

Compile the following .c file and run it with strace.  The steps are listed below:

# cat shm_example.c 
#include <stdio.h> 
#include <sys/shm.h> 
#include <sys/stat.h> 

int main () 
{
  int seg_id; 
  char* shm_ptr; 
  int segment_size; 
  const int seg_siz = 1024*1024; 

  seg_id = shmget (IPC_PRIVATE, seg_siz , IPC_CREAT | S_IRUSR | S_IWUSR ); 
  shm_ptr = (char*) shmat (seg_id, 0, 0); 
  shmdt (shm_ptr); 
  shmctl (seg_id, IPC_RMID, 0); 
  return 0; 
} 

# gcc shm_example.c -o ./a.out
# strace -etrace=shmat ./a.out
shmat(294912, 0, 0)                     = ?


Actual results:
# strace -etrace=shmat ./a.out
shmat(294912, 0, 0)                     = ?

Expected results:
# strace -etrace=shmat ./a.out
shmat(294912, 0, 0)                     = <the_attached_address>

Additional info:
I've confirmed that this is fixed in the upstream strace 4.7 version.  It would be really useful to make this fix available in the RHEL 6.x release stream.