acct: real_parent ppid

The ac_ppid field reported in process accounting records
should match what getppid() would have returned to that
process, regardless of whether a debugger is attached.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/acct.c

@@ -482,7 +482,7 @@ static void do_acct_process(struct file *file)
 #endif
 #if ACCT_VERSION==3
 	ac.ac_pid = current->tgid;
-	ac.ac_ppid = current->parent->tgid;
+	ac.ac_ppid = current->real_parent->tgid;
 #endif
 
 	spin_lock_irq(&current->sighand->siglock);