Index: head/sys/kern/sys_process.c
===================================================================
--- head/sys/kern/sys_process.c
+++ head/sys/kern/sys_process.c
@@ -504,6 +504,7 @@
     struct ptrace_lwpinfo32 *pl32)
 {
 
+	bzero(pl32, sizeof(*pl32));
 	pl32->pl_lwpid = pl->pl_lwpid;
 	pl32->pl_event = pl->pl_event;
 	pl32->pl_flags = pl->pl_flags;
@@ -1323,6 +1324,7 @@
 		} else
 #endif
 		pl = addr;
+		bzero(pl, sizeof(*pl));
 		pl->pl_lwpid = td2->td_tid;
 		pl->pl_event = PL_EVENT_NONE;
 		pl->pl_flags = 0;
@@ -1343,8 +1345,6 @@
 				pl->pl_siginfo = td2->td_si;
 			}
 		}
-		if ((pl->pl_flags & PL_FLAG_SI) == 0)
-			bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
 		if (td2->td_dbgflags & TDB_SCE)
 			pl->pl_flags |= PL_FLAG_SCE;
 		else if (td2->td_dbgflags & TDB_SCX)