Fixed level-A crash when cancel task execution

1 files changed, 21 insertions, 4 deletions

diff --git a/litmus/sched_mc.c b/litmus/sched_mc.c
index 5067b79b026b..9edf038ef164 100644
--- a/litmus/sched_mc.c
+++ b/litmus/sched_mc.c
@@ -492,6 +492,9 @@ static void check_for_preempt(struct domain *dom)
                         entry = crit_cpu(ce);
                         recheck = 1;
 
+                        /* Cache ready task */
+                        dom->peek_ready(dom);
+
                         raw_spin_lock(&entry->lock);
                         if (!can_use(ce))
                                 /* CPU disabled while locking! */
@@ -530,6 +533,8 @@ static void remove_from_all(struct task_struct* task)
         struct crit_entry *ce;
         struct domain *dom = get_task_domain(task);
 
+        QT_START;
+
         TRACE_MC_TASK(task, "Removing from everything\n");
         BUG_ON(!task);
 
@@ -551,7 +556,7 @@ static void remove_from_all(struct task_struct* task)
                                 link_task_to_cpu(entry, NULL);
                         }
                 } else {
-                        TRACE_MC_TASK(task, "Unlinked before we got lock!");
+                        TRACE_MC_TASK(task, "Unlinked before we got lock!\n");
                 }
                 if (update)
                         update_crit_levels(entry);
@@ -566,6 +571,7 @@ static void remove_from_all(struct task_struct* task)
 
         BUG_ON(is_queued(task));
         raw_spin_unlock(dom->lock);
+        QT_END;
 }
 
 /**
@@ -663,6 +669,7 @@ static lt_t __ce_timer_function(struct ce_dom_data *ce_data)
         struct domain *dom = ce->domain;
         struct task_struct *old_link = NULL;
         lt_t next_timer_abs;
+        QT_START;
 
         TRACE("MC level-A timer callback for CPU %d\n", ce_data->cpu);
 
@@ -692,6 +699,7 @@ static lt_t __ce_timer_function(struct ce_dom_data *ce_data)
                 raw_spin_unlock(dom->lock);
                 check_for_preempt(dom);
         }
+        QT_END;
         return next_timer_abs;
 }
 
@@ -734,11 +742,15 @@ static void mc_release_jobs(rt_domain_t* rt, struct bheap* tasks)
         struct task_struct *first = bheap_peek(rt->order, tasks)->value;
         struct domain *dom = get_task_domain(first);
 
+        QT_START;
+
         raw_spin_lock_irqsave(dom->lock, flags);
         TRACE(TS "Jobs released\n", TA(first));
         __merge_ready(rt, tasks);
         check_for_preempt(dom);
         raw_spin_unlock_irqrestore(dom->lock, flags);
+
+        QT_END;
 }
 
 /**
@@ -877,6 +889,7 @@ static struct task_struct* mc_schedule(struct task_struct* prev)
         struct cpu_entry* entry = &__get_cpu_var(cpus);
         int i, out_of_time, sleep, preempt, exists, blocks, global, lower;
         struct task_struct *dtask = NULL, *ready_task = NULL, *next = NULL;
+        QT_START;
 
         local_irq_save(flags);
         raw_spin_lock(&entry->lock);
@@ -944,12 +957,15 @@ static struct task_struct* mc_schedule(struct task_struct* prev)
                  */
                 raw_spin_unlock(&entry->lock);
                 raw_spin_lock(dom->lock);
+
+                /* Peek at task here to avoid lock use */
+                dtask = dom->peek_ready(dom);
+
                 raw_spin_lock(&entry->lock);
 
                 /* Now that we hold the domain lock...*/
                 fix_crit_position(ce);
 
-                dtask = dom->peek_ready(dom);
                 if (!entry->linked && !ce->linked && dtask && can_use(ce)) {
                         dom->take_ready(dom);
                         link_task_to_crit(ce, dtask);
@@ -977,9 +993,10 @@ static struct task_struct* mc_schedule(struct task_struct* prev)
         raw_spin_unlock(&entry->lock);
         local_irq_restore(flags);
         if (next) {
-                TRACE_TASK(next, "Picked this task\n");
+                TRACE_MC_TASK(next, "Picked this task\n");
         } else if (exists && !next)
                 TRACE_ENTRY(entry, "Becomes idle at %llu\n", litmus_clock());
+        QT_END;
         return next;
 }
 
@@ -987,7 +1004,7 @@ void mc_finish_switch(struct task_struct *prev)
 {
         struct cpu_entry* entry = &__get_cpu_var(cpus);
         entry->scheduled = is_realtime(current) ? current : NULL;
-        TRACE_TASK(prev, "Switched away from to " TS,
+        TRACE_TASK(prev, "Switched away from to " TS "\n",
                    TA(entry->scheduled));
 }