Index: sys/kern/subr_syscall.c
===================================================================
--- sys/kern/subr_syscall.c
+++ sys/kern/subr_syscall.c
@@ -49,8 +49,15 @@
 #include <sys/uio.h>
 #include <sys/ktrace.h>
 #endif
+#ifdef KDTRACE_HOOKS
+#include <sys/sysproto.h>
+#endif
 #include <security/audit/audit.h>
 
+#define IS_FORK(code) \
+	((code == AUE_FORK) || (code == AUE_VFORK) ||		\
+	    (code == AUE_RFORK) || (code == AUE_PDFORK))
+
 static inline int
 syscallenter(struct thread *td, struct syscall_args *sa)
 {
@@ -141,9 +148,12 @@
 
 #ifdef KDTRACE_HOOKS
 		/* Give the syscall:::return DTrace probe a chance to fire. */
-		if (systrace_probe_func != NULL && sa->callp->sy_return != 0)
+		if (systrace_probe_func != NULL && sa->callp->sy_return != 0) {
 			(*systrace_probe_func)(sa, SYSTRACE_RETURN,
 			    error ? -1 : td->td_retval[0]);
+			if (IS_FORK(sa->code))
+				(*systrace_probe_func)(sa, SYSTRACE_RETURN, 0);
+		}
 #endif
 		syscall_thread_exit(td, sa->callp);
 	}