Created attachment 854158 [details]
A patch file.

Description of problem:
strace -cf causes Segmentation fault before printing summary.

Version-Release number of selected component (if applicable):
strace-4.5.19-1.17.el6

How reproducible:
100%

Steps to Reproduce:
1. Install strace package and openjdk package.
2. Run "strace -cf java".

Actual results:
Segmentation fault

Expected results:
Summary is printed correctly.

Additional info:

The outf == NULL is the trigger when call_summary() in cleanup() is called.

  static void
  cleanup()
  {
  (...snipped...)
          if (cflag)
                  call_summary(outf);
  }

The outf == NULL is caused by assignments in handle_stopped_tcbs()
with tcp->outf == NULL and tcp->wait_status == 256 and tcp->pid == 0.

  static int
  handle_stopped_tcbs(struct tcb *tcp)
  {
          for (; tcp; tcp = tcp->next_need_service) {
                  int pid;
                  int status;
  
                  outf = tcp->outf;
                  status = tcp->wait_status;
                  pid = tcp->pid;
  (...snipped...)
  }

The tcp->outf == NULL is caused by assignments in droptcb() with
tcp->outf == stderr.

  void
  droptcb(tcp)
  struct tcb *tcp;
  {
          if (tcp->pid == 0)
                  return;
  (...snipped...)
          if (outfname && followfork > 1 && tcp->outf)
                  fclose(tcp->outf);
  
          tcp->outf = 0;
  }

Oh, why are we closing stderr when we will later use stderr at call_summary()?
Attached patch solves "strace -cf java" case, but does not solve
"strace -cf -o outfile java" case. I don't know how to fix this bug.

Regards.