diff --git a/a1.2.config b/a1.2.config
index a8a60a707a9d..ff905b05fba8 100644
--- a/a1.2.config
+++ b/a1.2.config
@@ -3755,9 +3755,8 @@ CONFIG_NVMEM_SYSFS=y
 # CONFIG_PECI is not set
 # CONFIG_HTE is not set
 CONFIG_SST=y
-CONFIG_SST_MEMLEAK=y
 # CONFIG_SST_BOUNDS is not set
-# CONFIG_SST_LOCKING is not set
+# CONFIG_SST_ASYNC_SOURCE is not set
 # end of Device Drivers
 
 #
diff --git a/drivers/sst/Kconfig b/drivers/sst/Kconfig
index 3dd56be559e8..98802edff6c7 100644
--- a/drivers/sst/Kconfig
+++ b/drivers/sst/Kconfig
@@ -4,27 +4,21 @@
 #
 
 menuconfig SST
-	bool "Modules for system software techniques"
+	tristate "Modules for system software techniques"
 	default y
 	help
       TODO
 
 if SST
-config SST_MEMLEAK
-	tristate "Memleak errors for exercise a1.2"
-	default n
-	help
-	  Enable memleaks for exercise a1.2
-
 config SST_BOUNDS
 	tristate "Out-of-bounds accesses for exercise a1.3"
 	default n
 	help
 	  Activate out-of-bounds accesses for exercise a1.3
 
-config SST_LOCKING
-	tristate "Faulty locking for exercise a1.4"
+config SST_ASYNC_SOURCE
+	tristate "Enable async source of messages from the universe"
 	default n
 	help
-	  Make locking for exercise a1.4 faulty
+	  This is needed for task a1.4
 endif
diff --git a/drivers/sst/boundedbuffer.c b/drivers/sst/boundedbuffer.c
index 64a72aabed0d..a1fb40bd985d 100644
--- a/drivers/sst/boundedbuffer.c
+++ b/drivers/sst/boundedbuffer.c
@@ -6,31 +6,36 @@
 #define OFFSET 0
 #endif
 
-noinline int is_full(volatile struct boundedbuffer *buffer) {
+void init_bbuffer(struct boundedbuffer *buffer) {
+	buffer->next_in = 0;
+	buffer->next_out = 0;
+	buffer->size = BOUNDEDBUFFER_SIZE;
+}
+
+int is_full(struct boundedbuffer *buffer) {
    	return (buffer->next_in + 1) % buffer->size == buffer->next_out;
 }
 
-noinline int is_empty(volatile struct boundedbuffer *buffer) {
+int is_empty(struct boundedbuffer *buffer) {
 	return buffer->next_out == buffer->next_in;
 }
 
-noinline int produce(volatile struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE data) {
+int produce(struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE data) {
 	if (is_full(buffer)) {
 		return -1;
 	}
 
-	buffer->data[buffer->next_in] = data;
+	buffer->data[buffer->next_in + OFFSET] = data;
 	buffer->next_in = (buffer->next_in + 1) % buffer->size;
 
 	return 0;
 }
 
-noinline int consume(volatile struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE *ret) {
+int consume(struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE *ret) {
 	if (is_empty(buffer)) {
 		return -1;
 	}
-	*ret = buffer->data[buffer->next_out];
-	buffer->data[buffer->next_out] = 0;
+	*ret = buffer->data[buffer->next_out + OFFSET];
 	buffer->next_out = (buffer->next_out + 1) % buffer->size;
 
 	return 0;
diff --git a/drivers/sst/boundedbuffer.h b/drivers/sst/boundedbuffer.h
index 0a98f385f6e0..64086e584a8b 100644
--- a/drivers/sst/boundedbuffer.h
+++ b/drivers/sst/boundedbuffer.h
@@ -21,8 +21,9 @@ struct boundedbuffer {
 	BOUNDEDBUFFER_STORAGE_TYPE data[BOUNDEDBUFFER_SIZE_REAL];
 };
 
-noinline int is_full(volatile struct boundedbuffer *buffer);
-noinline int is_empty(volatile struct boundedbuffer *buffer);
-noinline int produce(volatile struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE data);
-noinline int consume(volatile struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE *ret);
+void init_bbuffer(struct boundedbuffer *buffer);
+int is_full(struct boundedbuffer *buffer);
+int is_empty(struct boundedbuffer *buffer);
+int produce(struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE data);
+int consume(struct boundedbuffer *buffer, BOUNDEDBUFFER_STORAGE_TYPE *ret);
 #endif // __BOUNDEDBUFFER_H__
diff --git a/drivers/sst/sst_chrdev.c b/drivers/sst/sst_chrdev.c
index b159bbee4c00..06f03743be65 100644
--- a/drivers/sst/sst_chrdev.c
+++ b/drivers/sst/sst_chrdev.c
@@ -29,7 +29,7 @@ static ssize_t universe_read(struct file *file, char __user *buf, size_t count,
 	size_t len = 0;
 
 	if (sst_consume_answer(sst_info, &answer)) {
-		pr_err("Cannot read from answers!\n");
+		pr_debug("Cannot read from answers!\n");
 		return 0;
 	}
 	len = strlen(answer);
@@ -78,7 +78,7 @@ static struct class universe_class = {
 	.name		= SST_CHRDEV,
 };
 
-static int __init sst_chdev_init(void) {
+static int __init sst_chrdev_init(void) {
 	int err;
 
 	sst_chrdev_major = err = register_chrdev(0, SST_CHRDEV, &universe_fops);
@@ -99,11 +99,14 @@ static int __init sst_chdev_init(void) {
 	}
 	err = sst_init();
 	if (err) {
-		return err;
+		pr_err("Cannot init sst_common: %d\n", err);
+		goto out_device;
 	}
 	pr_notice("Loaded module %s\n", KBUILD_MODNAME);
 	return 0;
 
+out_device:
+	device_destroy(&universe_class, MKDEV(sst_chrdev_major, 0));
 out_class:
 	class_unregister(&universe_class);
 out_chrdev:
@@ -112,7 +115,7 @@ out:
 	return err;
 }
 
-static void __exit sst_chdev_exit(void) {
+static void __exit sst_chrdev_exit(void) {
 	sst_destroy();
 	device_destroy(&universe_class, MKDEV(sst_chrdev_major, 0));
 	class_unregister(&universe_class);
@@ -120,6 +123,6 @@ static void __exit sst_chdev_exit(void) {
 	pr_notice("Unloaded module %s\n", KBUILD_MODNAME);
 }
 
-module_init(sst_chdev_init);
-module_exit(sst_chdev_exit);
+module_init(sst_chrdev_init);
+module_exit(sst_chrdev_exit);
 MODULE_LICENSE("LGPL");
diff --git a/drivers/sst/sst_common.c b/drivers/sst/sst_common.c
index 0ab1d60da991..39126654a489 100644
--- a/drivers/sst/sst_common.c
+++ b/drivers/sst/sst_common.c
@@ -44,6 +44,9 @@ static int control_thread_work(void *data) {
 		if (err) {
 			pr_err("Questions was empty!\n");
 			continue;
+		} else if (question == NULL) {
+			pr_err("Question is NULL although ret value is 0.\n");
+			continue;
 		} else {
 			sst_debug("Received msg '%s' at 0x%lx\n", question, (uintptr_t)question);
 		}
@@ -52,7 +55,7 @@ static int control_thread_work(void *data) {
 			(question[len_question - 1] == '\n' && question[len_question - 2] == '?'))) {
 			my_answer = sst_answers[0];
 			for (i = 0; i < SST_MAX_QUESTIONS; i++) {
-				if (strcasecmp(question, sst_questions[i]) == 0) {
+				if (strcmp(question, sst_questions[i]) == 0) {
 					my_answer = sst_answers[i];
 					break;
 				}
@@ -93,8 +96,8 @@ int sst_init(void) {
 	spin_lock_init(&cur_sst_info->lock_answers);
 	sema_init(&cur_sst_info->answers_rdy, 0);
 	init_waitqueue_head(&cur_sst_info->wait);
-	cur_sst_info->questions.size = BOUNDEDBUFFER_SIZE_REAL;
-	cur_sst_info->answers.size = BOUNDEDBUFFER_SIZE_REAL;
+	init_bbuffer(&cur_sst_info->answers);
+	init_bbuffer(&cur_sst_info->questions);
 	sst_debug("Allocated private data for the universe at [0x%lx,0x%lx]\n", (uintptr_t)cur_sst_info, (uintptr_t)((uintptr_t)cur_sst_info + sizeof(*cur_sst_info)));
 	cur_sst_info->thread = kthread_create(control_thread_work, get_sst_info(), "sst-worker-%d", 1);
 	if (IS_ERR(cur_sst_info->thread)) {
@@ -118,6 +121,11 @@ EXPORT_SYMBOL(sst_destroy);
 
 int sst_produce_question(sst_info_t *info, char *value) {
 		int err = 0;
+
+		if (!info) {
+			return -1;
+		}
+		sst_debug("%s:info=%lx, questions=%lx\n", __func__, (uintptr_t)cur_sst_info, (uintptr_t)&info->questions);
 		spin_lock_bh(&info->lock_questions);
 		err = produce(&info->questions, value);
 		spin_unlock_bh(&info->lock_questions);
@@ -131,6 +139,11 @@ EXPORT_SYMBOL(sst_produce_question);
 int sst_produce_answer(sst_info_t *info, char *value) {
 		int err = 0;
 		unsigned long flags;
+
+		if (!info) {
+			return -1;
+		}
+		sst_debug("%s:info=%lx, answers=%lx\n", __func__, (uintptr_t)cur_sst_info, (uintptr_t)&info->answers);
 		spin_lock_irqsave(&info->lock_answers, flags);
 		err = produce(&info->answers, value);
 		spin_unlock_irqrestore(&info->lock_answers, flags);
@@ -141,6 +154,11 @@ EXPORT_SYMBOL(sst_produce_answer);
 
 int sst_consume_question(sst_info_t *info, char **value) {
 		int err = 0;
+
+		if (!info) {
+			return -1;
+		}
+		sst_debug("%s:info=%lx, questions=%lx\n", __func__, (uintptr_t)cur_sst_info, (uintptr_t)&info->questions);
 		spin_lock_bh(&info->lock_questions);
 		err = consume(&info->questions, value);
 		spin_unlock_bh(&info->lock_questions);
@@ -151,6 +169,11 @@ EXPORT_SYMBOL(sst_consume_question);
 int sst_consume_answer(sst_info_t *info, char **value) {
 		int err = 0;
 		unsigned long flags;
+
+		if (!info) {
+			return -1;
+		}
+		sst_debug("%s:info=%lx, answers=%lx\n", __func__, (uintptr_t)cur_sst_info, (uintptr_t)&info->answers);
 		if (down_trylock(&info->answers_rdy)) {
 			sst_debug("Sry. No answer for you!\n");
 			return -2;