Index: share/man/man7/security.7
===================================================================
--- share/man/man7/security.7
+++ share/man/man7/security.7
@@ -539,7 +539,8 @@
 .Va debug.kdb.enter
 sysctl.
 A panic or trap cannot be forced using the
-.Va debug.kdb.panic
+.Va debug.kdb.panic ,
+.Va debug.kdb.panic_str
 and other sysctl's.
 .It Ic 2
 Highly secure mode \- same as secure mode, plus disks may not be
Index: sys/kern/subr_kdb.c
===================================================================
--- sys/kern/subr_kdb.c
+++ sys/kern/subr_kdb.c
@@ -82,6 +82,7 @@
 static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS);
+static int kdb_sysctl_panic_str(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_stack_overflow(SYSCTL_HANDLER_ARGS);
@@ -109,6 +110,11 @@
     kdb_sysctl_panic, "I",
     "set to panic the kernel");
 
+SYSCTL_PROC(_debug_kdb, OID_AUTO, panic_str,
+    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
+    kdb_sysctl_panic_str, "A",
+    "set to panic the kernel");
+
 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap,
     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_trap, "I",
@@ -206,6 +212,20 @@
 	return (0);
 }
 
+static int
+kdb_sysctl_panic_str(SYSCTL_HANDLER_ARGS)
+{
+	int error;
+	static char buf[256]; /* static buffer to limit mallocs when panicing */
+
+	*buf = '\0';
+	error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
+	if (error != 0 || req->newptr == NULL)
+		return (error);
+	panic("kdb_sysctl_panic: %s", buf);
+	return (0);
+}
+
 static int
 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
 {