diff --git a/sys/alpha/alpha/db_trace.c b/sys/alpha/alpha/db_trace.c
index f84d1b9b291e..b8a200ceca18 100644
--- a/sys/alpha/alpha/db_trace.c
+++ b/sys/alpha/alpha/db_trace.c
@@ -60,6 +60,11 @@
 #include <ddb/db_output.h>
 #include <alpha/alpha/db_instruction.h>
 
+struct trace_request {
+	register_t ksp;
+	register_t pc;
+};
+
 /*
  * Information about the `standard' Alpha function prologue.
  */
@@ -260,8 +265,16 @@ db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count, char *m
 			frame = addr;
 		}
 	} else {
-		db_printf("alpha trace requires known PC =eject=\n");
-		return;
+		struct trace_request *tr;
+
+		tr = (struct trace_request *)addr;
+		if (tr->ksp >= KERNBASE && tr->pc >= KERNBASE) {
+			db_printf("alpha trace requires known PC =eject=\n");
+			return;
+		}
+		callpc = tr->pc;
+		addr = tr->ksp;
+		frame = addr;
 	}
 
 	while (count--) {
@@ -377,7 +390,17 @@ db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count, char *m
 	}
 }
 
+void
+db_stack_trace_cmd(void)
+{
+	struct trace_request tr;
 
+	__asm __volatile(
+		"	stq sp,%0 \n"
+		"	stq pc,%1 \n"
+		: "=r" (tr.ksp), "=r" (tr.pc));
+	db_stack_trace_cmd(&tr, 1, -1, NULL);
+}
 
 int
 db_md_set_watchpoint(addr, size)
diff --git a/sys/amd64/amd64/db_trace.c b/sys/amd64/amd64/db_trace.c
index 8ac4c01ab645..f3688c51c9a1 100644
--- a/sys/amd64/amd64/db_trace.c
+++ b/sys/amd64/amd64/db_trace.c
@@ -350,6 +350,7 @@ db_stack_trace_cmd(addr, have_addr, count, modif)
 		p = NULL;
 		frame = (struct i386_frame *)addr;
 		callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
+		frame = frame->f_frame;
 	}
 
 	first = TRUE;
@@ -470,6 +471,14 @@ DB_DRX_FUNC(dr6)
 DB_DRX_FUNC(dr7)
 
 
+void
+db_print_backtrace(void)
+{
+	register_t ebp;
+
+	__asm __volatile("mov %%ebp,%0\n" : "=r" (ebp));
+	db_stack_trace_cmd(ebp, 1, -1, NULL);
+}
 
 int
 i386_set_watch(watchnum, watchaddr, size, access, d)
diff --git a/sys/ddb/ddb.h b/sys/ddb/ddb.h
index ce3ffc41278a..1eb87ba0ce27 100644
--- a/sys/ddb/ddb.h
+++ b/sys/ddb/ddb.h
@@ -134,6 +134,9 @@ db_cmdfcn_t	ipc_port_print;
 db_cmdfcn_t	vm_page_print;
 #endif
 
+/* Scare the user with backtrace of curthread to console. */
+void		db_print_backtrace(void);
+
 /*
  * Command table.
  */
diff --git a/sys/i386/i386/db_trace.c b/sys/i386/i386/db_trace.c
index 8ac4c01ab645..f3688c51c9a1 100644
--- a/sys/i386/i386/db_trace.c
+++ b/sys/i386/i386/db_trace.c
@@ -350,6 +350,7 @@ db_stack_trace_cmd(addr, have_addr, count, modif)
 		p = NULL;
 		frame = (struct i386_frame *)addr;
 		callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
+		frame = frame->f_frame;
 	}
 
 	first = TRUE;
@@ -470,6 +471,14 @@ DB_DRX_FUNC(dr6)
 DB_DRX_FUNC(dr7)
 
 
+void
+db_print_backtrace(void)
+{
+	register_t ebp;
+
+	__asm __volatile("mov %%ebp,%0\n" : "=r" (ebp));
+	db_stack_trace_cmd(ebp, 1, -1, NULL);
+}
 
 int
 i386_set_watch(watchnum, watchaddr, size, access, d)
diff --git a/sys/ia64/ia64/db_trace.c b/sys/ia64/ia64/db_trace.c
index ffd8302217d9..df630b254e13 100644
--- a/sys/ia64/ia64/db_trace.c
+++ b/sys/ia64/ia64/db_trace.c
@@ -134,6 +134,11 @@ db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count, char *m
 	ia64_free_unwind_state(us);
 }
 
+void
+db_print_backtrace(void)
+{
+}
+
 int
 db_md_set_watchpoint(addr, size)
 	db_expr_t addr;
diff --git a/sys/powerpc/powerpc/db_trace.c b/sys/powerpc/powerpc/db_trace.c
index fe5efce57212..0ea97589317f 100644
--- a/sys/powerpc/powerpc/db_trace.c
+++ b/sys/powerpc/powerpc/db_trace.c
@@ -291,3 +291,7 @@ db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 	db_stack_trace_print(addr, have_addr, count, modif, db_printf);
 }
 
+void
+db_print_backtrace(void)
+{
+}
diff --git a/sys/sparc64/sparc64/db_trace.c b/sys/sparc64/sparc64/db_trace.c
index 417cb809c38f..92f7ccb6a307 100644
--- a/sys/sparc64/sparc64/db_trace.c
+++ b/sys/sparc64/sparc64/db_trace.c
@@ -305,3 +305,8 @@ db_utrace(struct thread *td, struct trapframe *tf)
 	}
 	db_printf("done\n");
 }
+
+void
+db_stack_trace_cmd(void)
+{
+}