Disabled preemption and local IRQs. Discovered another stack bug in the...

Disabled preemption and local IRQs. Discovered another stack bug in the Barrefish code where thc_done does not adequately clean up the used stacks resulting in memory leaks.

src/tests/ctx-switch/main.c

@@ -13,6 +13,7 @@
 #include <thcinternal.h>
 #include <awe_mapper.h>
 #include <linux/kernel.h>
+#include <linux/delay.h>
 #include <linux/module.h>
 #include "../test_helpers.h"
 
@@ -23,35 +24,62 @@ MODULE_LICENSE("GPL");
 static unsigned long ctx_switch_measurements[NUM_SWITCH_MEASUREMENTS];
 
 
-static int setup_and_run_test(void)
+static int test_fn(void* data)
 {
     unsigned long start_time, end_time, elapsed_time;
     uint32_t msg_id;
 
-    thc_init();
-    int i;    
-    for( i = 0; i < NUM_SWITCH_MEASUREMENTS; i++ )
-    {
-        DO_FINISH_(ctx_switch,{
-            ASYNC({
-                msg_id = awe_mapper_create_id();
-                THCYieldAndSave(msg_id);
-                end_time = test_fipc_stop_stopwatch();
-            });             
-            ASYNC({
-                start_time = test_fipc_start_stopwatch(); 
-                THCYieldToId(msg_id);
-                awe_mapper_remove_id(msg_id);
-                });             
-        });
-
-        ctx_switch_measurements[i] = end_time - start_time;
-    }
-    
-    printk(KERN_ERR "Timing results of performing %d switches between awe contexts:\n", NUM_SWITCH_MEASUREMENTS);
-    test_fipc_dump_time(ctx_switch_measurements, NUM_SWITCH_MEASUREMENTS);
-
-    thc_done();
+
+        preempt_disable();
+        local_irq_disable();
+
+            int i;    
+            for( i = 0; i < NUM_SWITCH_MEASUREMENTS; i++ )
+            {
+                LCD_MAIN({
+                thc_init();
+                    DO_FINISH_(ctx_switch,{
+                        ASYNC({
+                            msg_id = awe_mapper_create_id();
+                            //THCYieldAndSave(msg_id);
+                            THCYield();
+                            end_time = test_fipc_stop_stopwatch();
+                        });             
+                        ASYNC({
+                            start_time = test_fipc_start_stopwatch(); 
+                            //THCYieldToId(msg_id);
+                            THCYield();
+                            awe_mapper_remove_id(msg_id);
+                            });             
+                    });
+                thc_done();
+
+                ctx_switch_measurements[i] = end_time - start_time;
+                });
+            }
+        preempt_enable();
+        local_irq_enable();
+
+        printk(KERN_ERR "Timing results of performing %d switches between awe contexts:\n", NUM_SWITCH_MEASUREMENTS);
+        test_fipc_dump_time(ctx_switch_measurements, NUM_SWITCH_MEASUREMENTS);
+
+
+    return 0;
+}
+
+
+static int setup_and_run_test(void)
+{
+    struct task_struct* thread = test_pin_to_core(NULL, test_fn, 1);
+    int ret;
+    wake_up_process(thread);
+    msleep(1000);
+    ret = test_fipc_wait_for_thread(thread);
+
+	if (ret)
+		printk(KERN_ERR "Thread returned non-zero exit status %d\n", ret);
+	
+    return ret;
 }
 
 
@@ -59,7 +87,7 @@ static int __init ctx_switch_init(void)
 {
 	int ret = 0;
 
-	LCD_MAIN({ ret = setup_and_run_test(); });
+	ret = setup_and_run_test();
 
     return ret;
 }

src/tests/test_helpers.h

@@ -40,13 +40,12 @@
                                         \
         } while (0);
 
-static inline 
-struct task_struct *
-test_fipc_spawn_thread_with_channel(struct fipc_ring_channel *channel,
-				int (*threadfn)(void *data),
-				int cpu_pin)
+
+static inline
+struct task_struct*
+test_pin_to_core(void* thd_data, int (*threadfn)(void *data), int cpu_pin)
 {
-	struct cpumask cpu_core;
+ 	struct cpumask cpu_core;
 	struct task_struct* thread = NULL;
 
         if (cpu_pin > num_online_cpus()) {
@@ -56,7 +55,7 @@ test_fipc_spawn_thread_with_channel(struct fipc_ring_channel *channel,
 	/*
 	 * Create kernel thread
 	 */
-	thread = kthread_create(threadfn, channel, "AsyncIPC.%d", cpu_pin);
+	thread = kthread_create(threadfn, thd_data, "Async.%d", cpu_pin);
 	if (IS_ERR(thread)) {
 		pr_err("Error while creating kernel thread\n");
 		goto fail2;
@@ -80,6 +79,15 @@ fail1:
 	return thread;
 }
 
+static inline 
+struct task_struct *
+test_fipc_spawn_thread_with_channel(struct fipc_ring_channel *channel,
+				int (*threadfn)(void *data),
+				int cpu_pin)
+{
+   return test_pin_to_core(channel, threadfn, cpu_pin); 
+}
+
 static inline
 void
 test_fipc_release_thread(struct task_struct *thread)