diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
index 0ca4bec176da..21d627551c31 100644
--- a/sys/kern/kern_clock.c
+++ b/sys/kern/kern_clock.c
@@ -38,12 +38,12 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_ntp.h"
-#include "opt_ddb.h"
 #include "opt_watchdog.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/callout.h>
+#include <sys/kdb.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/ktr.h>
@@ -69,10 +69,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/gmon.h>
 #endif
 
-#ifdef DDB
-#include <ddb/ddb.h>
-#endif
-
 #ifdef DEVICE_POLLING
 extern void hardclock_device_poll(void);
 #endif /* DEVICE_POLLING */
@@ -543,12 +539,12 @@ watchdog_fire(void)
 	}
 	printf("Total        %20ju\n", (uintmax_t)inttotal);
 
-#ifdef DDB
-	db_print_backtrace();
-	Debugger("watchdog timeout");
-#else /* !DDB */
+#ifdef KDB
+	kdb_backtrace();
+	kdb_enter("watchdog timeout");
+#else
 	panic("watchdog timeout");
-#endif /* DDB */
+#endif /* KDB */
 }
 
 #endif /* SW_WATCHDOG */
diff --git a/sys/kern/kern_malloc.c b/sys/kern/kern_malloc.c
index 4bc3348b92ab..e966a4995358 100644
--- a/sys/kern/kern_malloc.c
+++ b/sys/kern/kern_malloc.c
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/kdb.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
@@ -208,7 +209,7 @@ malloc(size, type, flags)
 		static	int curerr, once;
 		if (once == 0 && ppsratecheck(&lasterr, &curerr, 1)) {
 			printf("Bad malloc flags: %x\n", indx);
-			backtrace();
+			kdb_backtrace();
 			flags |= M_WAITOK;
 			once++;
 		}
@@ -216,7 +217,7 @@ malloc(size, type, flags)
 #endif
 #if 0
 	if (size == 0)
-		Debugger("zero size malloc");
+		kdb_enter("zero size malloc");
 #endif
 #ifdef MALLOC_MAKE_FAILURES
 	if ((flags & M_NOWAIT) && (malloc_failure_rate != 0)) {
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
index 2fc79debf328..662cd4c6c664 100644
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
+#include <sys/kdb.h>
 #include <sys/kernel.h>
 #include <sys/ktr.h>
 #include <sys/lock.h>
@@ -585,11 +586,7 @@ _mtx_lock_spin(struct mtx *m, int opts, const char *file, int line)
 			}
 			if (i < 60000000)
 				DELAY(1);
-#ifdef DDB
-			else if (!db_active) {
-#else
-			else {
-#endif
+			else if (!kdb_active) {
 				printf("spin lock %s held by %p for > 5 seconds\n",
 				    m->mtx_object.lo_name, (void *)m->mtx_lock);
 #ifdef WITNESS
diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c
index fbf466075d33..edbbfdb1722d 100644
--- a/sys/kern/kern_shutdown.c
+++ b/sys/kern/kern_shutdown.c
@@ -37,9 +37,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_ddb.h"
-#include "opt_ddb_trace.h"
-#include "opt_ddb_unattended.h"
+#include "opt_kdb.h"
 #include "opt_hw_wdog.h"
 #include "opt_mac.h"
 #include "opt_panic.h"
@@ -52,6 +50,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/conf.h>
 #include <sys/cons.h>
 #include <sys/eventhandler.h>
+#include <sys/kdb.h>
 #include <sys/kernel.h>
 #include <sys/kthread.h>
 #include <sys/mac.h>
@@ -70,9 +69,6 @@ __FBSDID("$FreeBSD$");
 #include <machine/smp.h>
 
 #include <sys/signalvar.h>
-#ifdef DDB
-#include <ddb/ddb.h>
-#endif
 
 #ifndef PANIC_REBOOT_WAIT_TIME
 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
@@ -84,8 +80,8 @@ __FBSDID("$FreeBSD$");
  */
 #include <machine/stdarg.h>
 
-#ifdef DDB
-#ifdef DDB_UNATTENDED
+#ifdef KDB
+#ifdef KDB_UNATTENDED
 int debugger_on_panic = 0;
 #else
 int debugger_on_panic = 1;
@@ -93,14 +89,14 @@ int debugger_on_panic = 1;
 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW,
 	&debugger_on_panic, 0, "Run debugger on kernel panic");
 
-#ifdef DDB_TRACE
+#ifdef KDB_TRACE
 int trace_on_panic = 1;
 #else
 int trace_on_panic = 0;
 #endif
 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW,
 	&trace_on_panic, 0, "Print stack trace on kernel panic");
-#endif
+#endif /* KDB */
 
 int sync_on_panic = 1;
 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW,
@@ -127,7 +123,10 @@ const char *panicstr;
 
 int dumping;				/* system is dumping */
 static struct dumperinfo dumper;	/* our selected dumper */
-static struct pcb dumppcb;		/* "You Are Here" sign for dump-debuggers */
+
+/* Context information for dump-debuggers. */
+static struct pcb dumppcb;		/* Registers. */
+static lwpid_t dumptid;			/* Thread ID. */
 
 static void boot(int) __dead2;
 static void poweroff_wait(void *, int);
@@ -233,6 +232,7 @@ doadump(void)
 {
 
 	savectx(&dumppcb);
+	dumptid = curthread->td_tid;
 	dumping++;
 	dumpsys(&dumper);
 }
@@ -249,10 +249,8 @@ boot(int howto)
 	/* collect extra flags that shutdown_nice might have set */
 	howto |= shutdown_howto;
 
-#ifdef DDB
 	/* We are out of the debugger now. */
-	db_active = 0;
-#endif
+	kdb_active = 0;
 
 #ifdef SMP
 	if (smp_active)
@@ -457,22 +455,6 @@ shutdown_reset(void *junk, int howto)
 	/* NOTREACHED */ /* assuming reset worked */
 }
 
-/*
- * Print a backtrace if we can.
- */
-
-void
-backtrace(void)
-{
-
-#ifdef DDB
-	printf("Stack backtrace:\n");
-	db_print_backtrace();
-#else
-	printf("Sorry, need DDB option to print backtrace");
-#endif
-}
-
 #ifdef SMP
 static u_int panic_cpu = NOCPU;
 #endif
@@ -536,11 +518,11 @@ panic(const char *fmt, ...)
 #endif
 #endif
 
-#if defined(DDB)
+#ifdef KDB
 	if (newpanic && trace_on_panic)
-		backtrace();
+		kdb_backtrace();
 	if (debugger_on_panic)
-		Debugger ("panic");
+		kdb_enter("panic");
 #ifdef RESTARTABLE_PANICS
 	/* See if the user aborted the panic, in which case we continue. */
 	if (panicstr == NULL) {
diff --git a/sys/kern/kern_switch.c b/sys/kern/kern_switch.c
index a2fb0d8d2f58..768084c76b8c 100644
--- a/sys/kern/kern_switch.c
+++ b/sys/kern/kern_switch.c
@@ -92,6 +92,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/kdb.h>
 #include <sys/kernel.h>
 #include <sys/ktr.h>
 #include <sys/lock.h>
@@ -715,7 +716,7 @@ void
 panc(char *string1, char *string2)
 {
 	printf("%s", string1);
-	Debugger(string2);
+	kdb_enter(string2);
 }
 
 void
diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index f8f4dd7da22d..701630725e8b 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -37,12 +37,12 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_ddb.h"
 #include "opt_ktrace.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/condvar.h>
+#include <sys/kdb.h>
 #include <sys/kernel.h>
 #include <sys/ktr.h>
 #include <sys/lock.h>
@@ -57,9 +57,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 #include <sys/sysproto.h>
 #include <sys/vmmeter.h>
-#ifdef DDB
-#include <ddb/ddb.h>
-#endif
 #ifdef KTRACE
 #include <sys/uio.h>
 #include <sys/ktrace.h>
@@ -321,16 +318,15 @@ mi_switch(int flags, struct thread *newtd)
 
 	td->td_generation++;	/* bump preempt-detect counter */
 
-#ifdef DDB
 	/*
 	 * Don't perform context switches from the debugger.
 	 */
-	if (db_active) {
+	if (kdb_active) {
 		mtx_unlock_spin(&sched_lock);
-		db_print_backtrace();
-		db_error("Context switches not allowed in the debugger");
+		kdb_backtrace();
+		kdb_reenter();
+		panic("%s: did not reenter debugger", __func__);
 	}
-#endif
 
 	/*
 	 * Check if the process exceeds its cpu resource allocation.  If