From 319f197fcd73d401ac184244dbc51504443e1437 Mon Sep 17 00:00:00 2001
From: Mathieu Maret <mathieu.maret@gmail.com>
Date: Sun, 3 May 2020 23:13:17 +0200
Subject: [PATCH] Fix scheduler with sleeping task

---
 core/kthread.c | 15 ++++++++++-----
 core/main.c    |  2 +-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/core/kthread.c b/core/kthread.c
index 7ec8ef4..4038835 100644
--- a/core/kthread.c
+++ b/core/kthread.c
@@ -77,10 +77,13 @@ free_mem:
 
 void kthreadDelete(struct kthread *thread)
 {
+    uint32_t flags;
+    disable_IRQs(flags);
     list_delete(currentThread, thread);
 
     free((void *)thread->stackAddr);
     free((void *)thread);
+    restore_IRQs(flags);
 }
 
 struct kthread *kthreadSelectNext()
@@ -93,8 +96,7 @@ struct kthread *kthreadSelectNext()
             return nextThread;
         }
     }
-    assert("Cannot find next thread\n");
-    return nextThread;
+    return currentThread;
 }
 
 struct cpu_state *kthreadSwitch(struct cpu_state *prevCpu)
@@ -140,7 +142,9 @@ int kthreadYield()
         restore_IRQs(flags);
         return 0;
     }
-    current->state = READY;
+    assert(current->state == RUNNING);
+    assert(next->state == READY);
+    current->state       = READY;
     currentThread        = next;
     currentThread->state = RUNNING;
     cpu_context_switch(&current->cpuState, next->cpuState);
@@ -152,10 +156,11 @@ int kthreadMsleep(unsigned long msec)
 {
     uint32_t flags;
     disable_IRQs(flags);
-    struct kthread *next    = kthreadSelectNext();
     struct kthread *current = currentThread;
+    assert(current->state == RUNNING);
+    current->state       = SLEEPING;
+    struct kthread *next = kthreadSelectNext();
     assert(next != current);
-    current->state           = SLEEPING;
     current->jiffiesSleeping = msecs_to_jiffies(msec);
     assert(next->state == READY);
     currentThread        = next;
diff --git a/core/main.c b/core/main.c
index eed2156..cab937b 100644
--- a/core/main.c
+++ b/core/main.c
@@ -28,7 +28,7 @@ void idleThread(void *arg)
     (void)arg;
     while (1) {
         printIntDetails((jiffies / HZ), GREEN, BLACK, 0, VGA_HEIGHT - 1);
-        //kthreadYield();
+        kthreadYield();
     }
 }