From: Matthias Kruk <m@m10k.eu>
Date: Sat, 21 Mar 2020 17:45:19 +0000 (+0900)
Subject: sched/lazy: Make sure _lazy_tick() doesn't break if ctask is NULL, which happens... 
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=b4435716e23d3c5844e3015a0069dd87706b5123;p=corax

sched/lazy: Make sure _lazy_tick() doesn't break if ctask is NULL, which happens the first time it is called
---

diff --git a/kernel/sched/lazy.c b/kernel/sched/lazy.c
index 88f76c0..eed9823 100644
--- a/kernel/sched/lazy.c
+++ b/kernel/sched/lazy.c
@@ -27,38 +27,44 @@ static int _lazy_tick(struct sched_lazy *lazy)
 	ctask = task_get_current();
 	ret_val = 0;
 
-	task_lock(ctask);
+	if(ctask) {
+		task_lock(ctask);
 
-	if(ctask->t_state != TASK_STATE_EXIT) {
-		if(ctask->t_rslice) {
-			ctask->t_rslice--;
-		} else {
-			/* task has exhausted its time slice - reschedule */
-			ctask->t_rslice = ctask->t_tslice;
-			ctask->t_state = TASK_STATE_READY;
-			ret_val = 1;
+		if(ctask->t_state != TASK_STATE_EXIT) {
+			if(ctask->t_rslice) {
+				ctask->t_rslice--;
+			} else {
+				/* task has exhausted its time slice - reschedule */
+				ctask->t_rslice = ctask->t_tslice;
+				ctask->t_state = TASK_STATE_READY;
+				ret_val = 1;
+			}
 		}
-	}
 
-	task_unlock(ctask);
+		task_unlock(ctask);
+	} else {
+		ret_val = 1;
+	}
 
 	if(ret_val) {
 		/* rescheduling is required */
 		_LOCK(lazy);
 
-		/* put current task back on the ready queue */
-		ret_val = kq_nq(&(lazy->readyq), ctask);
-
-		if(ret_val < 0) {
-			/*
-			 * FIXME: could not put task back on ready queue - wat do?
-			 *
-			 * If we don't do anything here, the task would be silently
-			 * dropped by the scheduler and never get scheduled again.
-			 * Instead, it would be better if we could move it to a different
-			 * processor, which (on NUMA systems) might have enough memory
-			 * available to schedule the task.
-			 */
+		if(ctask) {
+			/* put current task back on the ready queue */
+			ret_val = kq_nq(&(lazy->readyq), ctask);
+
+			if(ret_val < 0) {
+				/*
+				 * FIXME: could not put task back on ready queue - wat do?
+				 *
+				 * If we don't do anything here, the task would be silently
+				 * dropped by the scheduler and never get scheduled again.
+				 * Instead, it would be better if we could move it to a different
+				 * processor, which (on NUMA systems) might have enough memory
+				 * available to schedule the task.
+				 */
+			}
 		}
 
 		/* get the first ready task */