Index: sys/amd64/amd64/vm_machdep.c
===================================================================
--- sys/amd64/amd64/vm_machdep.c
+++ sys/amd64/amd64/vm_machdep.c
@@ -193,6 +193,14 @@
 	td2->td_md.md_spinlock_count = 1;
 	td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
 	pmap_thread_init_invl_gen(td2);
+
+	/*
+	 * Copy the trap frame for the return to user mode as if from a syscall.
+	 * This copies most of the user mode register values.  Some of these
+	 * registers are rewritten by cpu_set_upcall() and linux_set_upcall().
+	 */
+	if ((td1->td_proc->p_flag & P_KPROC) == 0)
+		bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
 }
 
 /*
@@ -236,13 +244,6 @@
 	mdp2 = &p2->p_md;
 	bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
 
-	/*
-	 * Copy the trap frame for the return to user mode as if from a
-	 * syscall.  This copies most of the user mode register values.
-	 */
-	td2->td_frame = (struct trapframe *)td2->td_md.md_stack_base - 1;
-	bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
-
 	/* Set child return values. */
 	p2->p_sysent->sv_set_fork_retval(td2);
 
@@ -603,14 +604,7 @@
 	copy_thread(td0, td);
 
 	/*
-	 * Copy user general-purpose registers.
-	 *
-	 * Some of these registers are rewritten by cpu_set_upcall()
-	 * and linux_set_upcall().
-	 */
-	bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
-
-	/* If the current thread has the trap bit set (i.e. a debugger had
+	 * If the current thread has the trap bit set (i.e. a debugger had
 	 * single stepped the process to the system call), we need to clear
 	 * the trap flag from the new frame. Otherwise, the new thread will
 	 * receive a (likely unexpected) SIGTRAP when it executes the first