change behaviour on too large argument

Move msg_count handling to hello2 to comply with lab5 requirements

Makefile

@@ -2,13 +2,17 @@
 ifneq ($(KERNELRELEASE),)
 # kbuild part of makefile
 obj-m   := hello1.o hello2.o
-ccflags-y := -I$(obj)/inc
+ccflags-y := -I$(obj)/inc -g
 else
 # normal makefile
 KDIR ?= /lib/modules/`uname -r`/build
 
 default:
 	$(MAKE) -C $(KDIR) M=$$PWD
+	cp hello1.ko hello1.ko.unstripped
+	$(CROSS_COMPILE)strip -g hello1.ko
+
 clean:
 	$(MAKE) -C $(KDIR) M=$$PWD clean
+
 endif

hello1.c

@@ -44,10 +44,10 @@ struct TimingList {
 	ktime_t t_after;
 };
 
-static unsigned int msg_count = 1;
 static struct TimingList *tl_head;
+static unsigned int bug_generator;
 
-static struct TimingList* write_first_node(void)
+static struct TimingList *write_first_node(void)
 {
 	tl_head = kmalloc(sizeof(struct TimingList), GFP_KERNEL);
 	tl_head->next = NULL;
@@ -55,18 +55,22 @@ static struct TimingList* write_first_node(void)
 	return tl_head;
 }
 
-static struct TimingList* insert_next_node(struct TimingList *tail)
+static struct TimingList *insert_next_node(struct TimingList *tail)
 {
 	struct TimingList *new_tl_node = kmalloc(sizeof(struct TimingList),
 						GFP_KERNEL);
 
-	tail->next = new_tl_node;
+	if (bug_generator == 2) {
-	new_tl_node->next = NULL;
+		new_tl_node = NULL;
+	} else {
+		tail->next = new_tl_node;
+		new_tl_node->next = NULL;
+	}
 
 	return new_tl_node;
 }
 
-static struct TimingList* add_new_node(struct TimingList *tail)
+static struct TimingList *add_new_node(struct TimingList *tail)
 {
 	if (tail == NULL)
 		return write_first_node();
@@ -94,27 +98,21 @@ void destroy_list(void)
 		curr_tl = next_tl;
 	}
 }
+EXPORT_SYMBOL(destroy_list);
 
 static int __init hello_init(void)
 {
-	if (msg_count > 10) {
-		pr_err("Error: msg_count too large (%d > 10)\n", msg_count);
-		return -EINVAL;
-	}
-
-	if (msg_count == 0 || msg_count >= 5) {
-		pr_warn("Warning: msg_count = %d (msg_count == 0 or 5 <= msg_count <= 10)\n", msg_count);
-	}
-
 	return 0;
 }
 
-void print_hello(void)
+void print_hello(int msg_count)
 {
 	int i;
 	struct TimingList *current_tail = tl_head;
 
 	for (i = 0; i < msg_count; i++) {
+		bug_generator = i;
+
 		current_tail = add_new_node(current_tail);
 
 		current_tail->t_before = ktime_get();
@@ -122,17 +120,13 @@ void print_hello(void)
 		current_tail->t_after = ktime_get();
 	}
 }
+EXPORT_SYMBOL(print_hello);
 
 static void __exit hello_exit(void)
 {
 	destroy_list();
 }
 
-module_param(msg_count, uint, 0444);
-MODULE_PARM_DESC(msg_count, "Amount of hello world outputs on load");
-
-EXPORT_SYMBOL(print_hello);
-EXPORT_SYMBOL(destroy_list);
 
 module_init(hello_init);
 module_exit(hello_exit);

hello2.c

@@ -40,9 +40,16 @@ MODULE_AUTHOR("Serhii Popovych <serhii.popovych@globallogic.com>");
 MODULE_DESCRIPTION("Hello, world in Linux Kernel Training");
 MODULE_LICENSE("Dual BSD/GPL");
 
+static unsigned int msg_count = 1;
+
 static int __init hello_init(void)
 {
-	print_hello();
+	BUG_ON(msg_count > 10);
+
+	if (msg_count == 0 || msg_count >= 5)
+		pr_warn("Warning: msg_count = %d (msg_count == 0 or 5 <= msg_count <= 10)\n", msg_count);
+
+	print_hello(msg_count);
 	return 0;
 }
 
@@ -51,5 +58,8 @@ static void __exit hello_exit(void)
 	destroy_list();
 }
 
+module_param(msg_count, uint, 0444);
+MODULE_PARM_DESC(msg_count, "Amount of hello world outputs on load");
+
 module_init(hello_init);
 module_exit(hello_exit);

inc/hello1.h

@@ -1,2 +1,2 @@
-void print_hello(void);
+void print_hello(int msg_count);
 void destroy_list(void);

test.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+if [ -z "$1" ]; then
+	echo "Error: no script supplied"
+	echo "Usage: $0 path/to/testing/script"
+	exit 1
+fi
+
+while read l; do
+	if [ -z "$l" ]; then
+		continue;
+	fi;
+
+	echo "$ $l";
+	$($l);
+
+	echo -e ""
+done < $1

tests/lab5-test

@@ -0,0 +1,33 @@
+insmod hello2.ko
+
+insmod hello1.ko
+
+insmod hello2.ko
+rmmod hello2.ko
+
+insmod hello2.ko msg_count=0
+rmmod hello2.ko
+
+insmod hello2.ko msg_count=1
+rmmod hello2.ko
+
+insmod hello2.ko msg_count=3
+rmmod hello2.ko
+
+insmod hello2.ko msg_count=5
+rmmod hello2.ko
+
+insmod hello2.ko msg_count=8
+rmmod hello2.ko
+
+insmod hello2.ko msg_count=10
+rmmod hello2.ko
+
+insmod hello2.ko msg_count=12
+rmmod hello2.ko
+
+insmod hello2.ko
+rmmod hello1.ko
+
+rmmod hello2.ko
+rmmod hello1.ko