m32r: PTRACE_SINGLESTEP sets PT_DTRACE, it is never used except cleared
after do_execve().

--- PTRACE/arch/m32r/kernel/process.c~DT_4_m32r	2009-04-06 00:03:35.000000000 +0200
+++ PTRACE/arch/m32r/kernel/process.c	2009-04-22 22:01:44.000000000 +0200
@@ -302,11 +302,6 @@ asmlinkage int sys_execve(char __user *u
 		goto out;
 
 	error = do_execve(filename, uargv, uenvp, &regs);
-	if (error == 0) {
-		task_lock(current);
-		current->ptrace &= ~PT_DTRACE;
-		task_unlock(current);
-	}
 	putname(filename);
 out:
 	return error;
--- PTRACE/arch/m32r/kernel/ptrace.c~DT_4_m32r	2009-04-06 00:03:35.000000000 +0200
+++ PTRACE/arch/m32r/kernel/ptrace.c	2009-04-22 22:00:13.000000000 +0200
@@ -676,10 +676,6 @@ arch_ptrace(struct task_struct *child, l
 		if (!valid_signal(data))
 			break;
 		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		if ((child->ptrace & PT_DTRACE) == 0) {
-			/* Spurious delayed TF traps may occur */
-			child->ptrace |= PT_DTRACE;
-		}
 
 		/* Compute next pc.  */
 		pc = get_stack_long(child, PT_BPC);