diff --git a/sys/kern/kern_mib.c b/sys/kern/kern_mib.c
--- a/sys/kern/kern_mib.c
+++ b/sys/kern/kern_mib.c
@@ -754,6 +754,10 @@
     CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
     0, 0, sysctl_kern_pid_max, "I", "Maximum allowed pid");
 
+SYSCTL_INT(_kern, OID_AUTO, pid_max_limit, CTLFLAG_RD,
+    SYSCTL_NULL_INT_PTR, PID_MAX,
+    "Maximum allowed pid (kern.pid_max) top limit");
+
 #include <sys/bio.h>
 #include <sys/buf.h>
 SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -955,7 +955,7 @@
  * in a pid_t, as it is used to represent "no process group".
  */
 #define	PID_MAX		99999
-#define	NO_PID		100000
+#define	NO_PID		(PID_MAX + 1)
 #define	THREAD0_TID	NO_PID
 extern pid_t pid_max;