diff --git a/sched/task.c b/sched/task.c
index 92011ad..4cd26a5 100644
--- a/sched/task.c
+++ b/sched/task.c
@@ -17,7 +17,10 @@ static struct object_type task_type = {
 static struct task *__kernel_task;
 static struct task *__idle_task;
 
-static spin_lock_t task_list_lock;
+static spin_lock_t pid_map_lock = SPIN_LOCK_INIT;
+static DECLARE_BITMAP(pid_map, PID_MAX);
+
+static spin_lock_t task_list_lock = SPIN_LOCK_INIT;
 static struct btree task_list;
 
 BTREE_DEFINE_SIMPLE_GET(
@@ -45,6 +48,31 @@ void idle(void)
 	}
 }
 
+static unsigned int pid_alloc(void)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&pid_map_lock, &flags);
+
+	unsigned int pid = bitmap_lowest_clear(pid_map, PID_MAX);
+	if (pid != BITMAP_NPOS) {
+		bitmap_set(pid_map, pid);
+	}
+
+	spin_unlock_irqrestore(&pid_map_lock, flags);
+
+	return pid;
+}
+
+static void pid_free(unsigned int pid)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&pid_map_lock, &flags);
+
+	bitmap_clear(pid_map, pid);
+
+	spin_unlock_irqrestore(&pid_map_lock, flags);
+}
+
 kern_status_t setup_kernel_task(void)
 {
 	__kernel_task = task_alloc();
diff --git a/sched/thread.c b/sched/thread.c
index accddc7..251423f 100644
--- a/sched/thread.c
+++ b/sched/thread.c
@@ -6,8 +6,6 @@
 
 #define THREAD_CAST(p) OBJECT_C_CAST(struct thread, thr_base, &thread_type, p)
 
-static DECLARE_BITMAP(thread_ids, THREAD_MAX) = {0};
-
 static struct object_type thread_type = {
 	.ob_name = "thread",
 	.ob_size = sizeof(struct thread),
@@ -33,8 +31,7 @@ struct thread *thread_alloc(void)
 
 kern_status_t thread_init(struct thread *thr, uintptr_t ip)
 {
-	thr->tr_id = bitmap_lowest_clear(thread_ids, THREAD_MAX);
-	bitmap_set(thread_ids, thr->tr_id);
+	thr->tr_id = thr->tr_parent->t_next_thread_id++;
 
 	thr->tr_prio = PRIO_NORMAL;
 	thr->tr_state = THREAD_READY;
@@ -85,8 +82,7 @@ struct thread *create_kernel_thread(void (*fn)(void))
 	struct task *kernel = kernel_task();
 	struct thread *thr = thread_alloc();
 
-	thr->tr_id = 1;
-	bitmap_set(thread_ids, 1);
+	thr->tr_id = kernel->t_next_thread_id++;
 
 	thr->tr_parent = kernel;
 	thr->tr_prio = PRIO_NORMAL;
@@ -110,8 +106,7 @@ struct thread *create_idle_thread(void)
 	struct task *idle = idle_task();
 	struct thread *thr = thread_alloc();
 
-	thr->tr_id = 0;
-	bitmap_set(thread_ids, 0);
+	thr->tr_id = idle->t_next_thread_id++;
 
 	thr->tr_parent = idle;
 	thr->tr_prio = PRIO_NORMAL;