insmod 失败并显示“模块中的未知符号”
insmod fails with “Unknown symbol in module”
我正在使用 Linuxmint Cinnamon 19 Ubuntu 18.04，内核版本 4.15.0-20-generic
编译时看到的如下：
make
make -C /lib/modules/`uname -r`/build SUBDIRS=/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator modules
make[1]: Entering directory '/usr/src/linux-headers-4.15.0-20-generic'
CC [M] /home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.o
Building modules, stage 2.
MODPOST 1 modules
WARNING: "STUB_stop_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_issue_request" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_start_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
CC /home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.mod.o
LD [M] /home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko
make[1]: Leaving directory '/usr/src/linux-headers-4.15.0-20-generic'
然后我尝试使用 sudo insmod elevator.ko
安装模块
insmod: ERROR: could not insert module elevator.ko: Unknown symbol in module
在日志中看到：
消息 |尾
[ 7.922763] 00:00:00.000285 main Executable: /opt/VBoxGuestAdditions-5.2.4/sbin/VBoxService
00:00:00.000286 main Process ID: 832
00:00:00.000286 main Package type: LINUX_64BITS_GENERIC
[ 7.923912] 00:00:00.001432 main 5.2.4 r119785 started. Verbose level = 0
[ 11.048520] ISO 9660 Extensions: Microsoft Joliet Level 3
[ 11.052008] ISO 9660 Extensions: RRIP_1991A
[ 86.413368] elevator: loading out-of-tree module taints kernel.
[ 86.413422] elevator: Unknown symbol STUB_stop_elevator (err 0)
[ 86.413438] elevator: Unknown symbol STUB_issue_request (err 0)
[ 86.413452] elevator: Unknown symbol STUB_start_elevator (err 0)
生成文件
obj-y := start_elevator.o issue_request.o stop_elevator.o
obj-m := elevator.o
KBUILD_CFLAGS += -fno-pie
PWD := $(shell pwd)
KDIR := /lib/modules/`uname -r`/build
default:
$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
clean:
rm -f *.o *.ko *.mod.* Module.* modules.*
elevator.c
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/linkage.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/uaccess.h>
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Simulates elevator");
#define ENTRY_NAME "elevator"
#define ENTRY_SIZE 700
#define PERMS 0644
#define PARENT NULL
static struct file_operations fops;
static char * message;
static int read_p;
enum States { OFFLINE, IDLE, LOADING, UP, DOWN };
#define MAX_PASSENGER_UNITS 10
#define MAX_WEIGHT_INT 15
#define MAX_WEIGHT_DEC 0
struct thread_parameter
{
enum States Current_State;
int Current_Floor;
int Next_Floor;
int Waiting_Passengers[10];
int Total_Passengers[10];
struct
{
int pass_units;
int weight_int;
int weight_dec;
} Current_Load;
struct list_head list;
int id;
struct task_struct * kthread;
struct mutex mutex;
};
typedef struct
{
int src;
int dst;
int pass_units;
int weight_int;
int weight_dec;
struct list_head list;
} Passenger;
struct thread_parameter elevator;
struct list_head list;
struct list_head elev;
bool stop;
/*************************************************************************/
extern int (*STUB_start_elevator)(void);
int my_start_elevator(void)
{
// start_elevator implementation
int i;
if (elevator.Current_State != OFFLINE)
return 1;
else
{
// try to initialize elevator:
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
elevator.Current_Floor = 1;
elevator.Next_Floor = 1;
elevator.Current_Load.pass_units = 0;
elevator.Current_Load.weight_int = 0;
elevator.Current_Load.weight_dec = 0;
elevator.Current_State = IDLE;
for (i = 0; i < 10; i++)
{
elevator.Waiting_Passengers[i] = 0;
elevator.Total_Passengers[i] = 0;
}
}
mutex_unlock(&elevator.mutex);
if (elevator.Current_State != IDLE)
return -1;
}
return 0;
}
/*************************************************************************/
int load_elev(Passenger * p)
{
struct list_head * temp;
struct list_head * dummy;
bool can_get_on = true;
bool remove = false;
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src != elevator.Current_Floor)
can_get_on = false;
if ((elevator.Current_Load.pass_units + p->pass_units) >
MAX_PASSENGER_UNITS)
can_get_on = false;
if ((elevator.Current_Load.weight_int + p->weight_int) >
MAX_WEIGHT_INT)
can_get_on = false;
if ((elevator.Current_Load.weight_int + p->weight_int) ==
MAX_WEIGHT_INT &&
(elevator.Current_Load.weight_dec == 5 ||
p->weight_dec == 5))
can_get_on = false;
if (p->dst == elevator.Current_Floor)
remove = true;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
if (can_get_on && !remove)
{
if (elevator.Current_Load.pass_units == 0)
INIT_LIST_HEAD(&elev);
elevator.Current_Load.pass_units += p->pass_units;
elevator.Current_Load.weight_int += p->weight_int;
if (elevator.Current_Load.weight_dec == 5 &&
p->weight_dec == 5)
{
elevator.Current_Load.weight_int++;
elevator.Current_Load.weight_dec = 0;
}
else
{
elevator.Current_Load.weight_dec += p->weight_dec;
}
elevator.Waiting_Passengers[elevator.Current_Floor - 1]--;
list_move_tail(temp, &elev);
}
else if (remove)
{
elevator.Waiting_Passengers[elevator.Current_Floor - 1]--;
list_del(temp);
kfree(p);
}
}
mutex_unlock(&elevator.mutex);
return 0;
}
int unload_elev(Passenger * p)
{
// declare some temporary pointers
struct list_head * temp;
struct list_head * dummy;
// use this since you need to change the pointers
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &elev)
{
p = list_entry(temp, Passenger, list);
if (p->dst == elevator.Current_Floor)
{
elevator.Current_Load.pass_units -= p->pass_units;
elevator.Current_Load.weight_int -= p->weight_int;
if (elevator.Current_Load.weight_dec == 0 &&
p->weight_dec == 5)
{
elevator.Current_Load.weight_int--;
elevator.Current_Load.weight_dec = 5;
}
else
{
elevator.Current_Load.weight_dec -=
p->weight_dec;
}
elevator.Total_Passengers[p->src - 1]++;
list_del(temp); // init ver also reinits list
kfree(p); // remember to free allocated data
}
}
}
mutex_unlock(&elevator.mutex);
return 0;
}
/*************************************************************************/
int find_next_floor_up(int current_floor)
{
struct list_head * temp;
Passenger * p;
int next_floor = -1;
int closest_floor = 11; //set this initially
if (elevator.Current_Load.pass_units > 0)
{
list_for_each(temp, &elev)
{
p = list_entry(temp, Passenger, list);
// for each passenger, if their dest is greater
// than current floor
// (i.e. they're going up), and if their dest is less
// than the current closest_floor
if (p->dst > current_floor && p->dst < closest_floor)
{
//make this our next_floor
next_floor = p->dst;
//update closest_floor to this particular passenger's
closest_floor = p->dst;
}
}
list_for_each(temp, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src > current_floor && p->src <= closest_floor &&
p->dst > current_floor)
{
next_floor = p->src;
closest_floor = p->src;
}
}
}
return next_floor;
}
int find_next_floor_down(int current_floor)
{
struct list_head * temp;
Passenger * p;
int next_floor = -1;
int closest_floor = 0;
if (elevator.Current_Load.pass_units > 0)
{
list_for_each(temp, &elev)
{
p = list_entry(temp, Passenger, list);
if (p->dst < current_floor && p->dst > closest_floor)
{
next_floor = p->dst;
closest_floor = p->dst;
}
}
list_for_each(temp, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src < current_floor && p->src >= closest_floor &&
p->dst < current_floor)
{
next_floor = p->src;
closest_floor = p->src;
}
}
}
return next_floor;
}
/*************************************************************************/
extern int (*STUB_issue_request)(int, int, int);
int my_issue_request(int p_type, int start_floor, int dest_floor)
{
// issue_request implementation
Passenger * p = NULL;
struct list_head * temp;
struct list_head * dummy;
if (elevator.Current_State == IDLE)
INIT_LIST_HEAD(&list);
p = kmalloc(sizeof(Passenger), __GFP_RECLAIM);
printk(KERN_NOTICE "MY_ISSUE_REQUEST FUNCTION ENTERED\n");
if (p_type < 1 || p_type > 4 ||
start_floor < 1 || start_floor > 10 ||
dest_floor < 1 || dest_floor > 10)
{
return 1;
}
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
p->src = start_floor;
p->dst = dest_floor;
p->pass_units = 0;
p->weight_int = 0;
p->weight_dec = 0;
switch (p_type)
{
case 1:
{
p->pass_units = 1;
p->weight_int = 1;
p->weight_dec = 0;
break;
}
case 2:
{
p->pass_units = 1;
p->weight_int = 0;
p->weight_dec = 5;
break;
}
case 3:
{
p->pass_units = 2;
p->weight_int = 2;
p->weight_dec = 0;
break;
}
case 4:
{
p->pass_units = 2;
p->weight_int = 3;
p->weight_dec = 0;
break;
}
}
}
mutex_unlock(&elevator.mutex);
if (!stop)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_add_tail(&p->list, &list);
elevator.Waiting_Passengers[p->src - 1]++;
}
mutex_unlock(&elevator.mutex);
if (elevator.Current_State == IDLE)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
if (p->src == elevator.Current_Floor)
{
elevator.Current_State = LOADING;
elevator.Next_Floor = p->dst;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
if (elevator.Current_Floor != p->src)
elevator.Next_Floor = p->src;
if (elevator.Next_Floor > elevator.Current_Floor)
elevator.Current_State = UP;
else if (elevator.Next_Floor < elevator.Current_Floor)
elevator.Current_State = DOWN;
}
mutex_unlock(&elevator.mutex);
}
else if (elevator.Current_State == UP)
{
if (elevator.Current_Load.pass_units == 0)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
elevator.Next_Floor = p->src;
break;
}
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src > elevator.Current_Floor &&
p->src <= elevator.Next_Floor &&
p->dst > elevator.Current_Floor)
{
elevator.Next_Floor = p->src;
}
}
}
mutex_unlock(&elevator.mutex);
}
}
else if (elevator.Current_State == DOWN)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src < elevator.Current_Floor &&
p->src >= elevator.Next_Floor &&
p->dst < elevator.Current_Floor)
{
elevator.Next_Floor = p->src;
}
}
}
mutex_unlock(&elevator.mutex);
}
}
return 0;
}
/*************************************************************************/
extern int (*STUB_stop_elevator)(void);
int my_stop_elevator(void)
{
// stop_elevator implementation
/*
deactivates elevator, elevator will
process no more new requests, but will
offload all current passengers
*/
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
stop = true;
}
mutex_unlock(&elevator.mutex);
while (elevator.Current_Load.pass_units != 0){}
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
elevator.Current_State = OFFLINE;
elevator.Current_Floor = 0;
elevator.Next_Floor = 0;
}
mutex_unlock(&elevator.mutex);
return 0;
}
/*************************************************************************/
int elevator_service(void * data)
{
struct thread_parameter * parm = data;
Passenger * p = NULL;
struct list_head * temp;
struct list_head * dummy;
int i;
bool waiting = false;
printk(KERN_NOTICE "ELEVATOR_SERVICE FUNCTION ENTERED\n");
while (!kthread_should_stop())
{
if (parm->Current_State != OFFLINE && parm->Current_State != IDLE)
{
if (parm->Current_State == LOADING)
{
ssleep(1);
// if there are passengers on elevator, call unload_elev
if (parm->Current_Load.pass_units > 0)
unload_elev(p);
if (!stop)
{
// if stop_elevator hasn't been called, call load_elev
load_elev(p);
}
else
{
// if stop_elevator has been called, delete
// all waiting passengers from list
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
list_del(temp);
kfree(p);
}
}
mutex_unlock(&elevator.mutex);
}
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
for (i = 0; i < 10; i++)
{
if (parm->Waiting_Passengers[i] > 0)
waiting = true;
}
}
mutex_unlock(&elevator.mutex);
// if there are no passengers on elevator
// and no passengers waiting on any floor
if (parm->Current_Load.pass_units == 0 && !waiting)
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_State = IDLE;
}
mutex_unlock(&elevator.mutex);
}
// if there are passengers on the elevator
// and no passengers waiting on any floor
else if (parm->Current_Load.pass_units > 0 && !waiting)
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &elev)
{
p = list_entry(temp, Passenger, list);
parm->Next_Floor = p->dst;
break;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
if (parm->Next_Floor > parm->Current_Floor)
{
if (find_next_floor_up(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_up(
parm->Current_Floor);
}
parm->Current_State = UP;
}
else
{
if (find_next_floor_down(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_down(
parm->Current_Floor);
}
parm->Current_State = DOWN;
}
}
mutex_unlock(&elevator.mutex);
}
// if there are no passengers on the elevator
// and at least one passenger is waiting on a floor
else if (parm->Current_Load.pass_units == 0 && waiting)
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
parm->Next_Floor = p->src;
break;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
if (parm->Next_Floor > parm->Current_Floor)
{
if (find_next_floor_up(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_up(
parm->Current_Floor);
}
parm->Current_State = UP;
}
else
{
if (find_next_floor_down(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_down(
parm->Current_Floor);
}
parm->Current_State = DOWN;
}
}
mutex_unlock(&elevator.mutex);
}
// if there is at least one passenger on the elevator
// and at least one passenger waiting on a floor
else
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &elev)
{
p = list_entry(temp, Passenger, list);
parm->Next_Floor = p->dst;
break;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
if (parm->Next_Floor > parm->Current_Floor)
{
if (find_next_floor_up(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_up(
parm->Current_Floor);
}
parm->Current_State = UP;
}
else
{
if (find_next_floor_down(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_down(
parm->Current_Floor);
}
parm->Current_State = DOWN;
}
}
mutex_unlock(&elevator.mutex);
}
}
else if (parm->Current_State == UP)
{
while (parm->Current_Floor != parm->Next_Floor)
{
ssleep(2);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_Floor++;
}
mutex_unlock(&elevator.mutex);
}
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_State = LOADING;
}
mutex_unlock(&elevator.mutex);
}
else // (parm->Current_State == DOWN)
{
while (parm->Current_Floor != parm->Next_Floor)
{
ssleep(2);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_Floor--;
}
mutex_unlock(&elevator.mutex);
}
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_State = LOADING;
}
mutex_unlock(&elevator.mutex);
}
}
}
return 0;
}
void thread_init_parameter(struct thread_parameter * parm)
{
parm->Current_State = OFFLINE;
mutex_init(&parm->mutex);
parm->kthread = kthread_run(elevator_service, parm,
"elevator in service");
}
/*************************************************************************/
int elevator_proc_open(struct inode *sp_inode, struct file *sp_file)
{
char * buf = kmalloc (sizeof(char) * 100, __GFP_RECLAIM);
int i;
if (buf == NULL)
{
printk(KERN_WARNING "print_time");
return -ENOMEM;
}
printk(KERN_INFO "proc called open\n");
printk(KERN_NOTICE "PROC_OPEN FUNCTION ENTERED\n");
read_p = 1;
message = kmalloc(sizeof(char) * ENTRY_SIZE,
__GFP_RECLAIM | __GFP_IO | __GFP_FS);
if (message == NULL)
{
printk(KERN_WARNING "time_proc_open");
return -ENOMEM;
}
strcpy(message, "");
switch (elevator.Current_State)
{
case 0:
{
sprintf(buf, "State: OFFLINE\n");
break;
}
case 1:
{
sprintf(buf, "State: IDLE\n");
break;
}
case 2:
{
sprintf(buf, "State: LOADING\n");
break;
}
case 3:
{
sprintf(buf, "State: UP\n");
break;
}
case 4:
{
sprintf(buf, "State: DOWN\n");
break;
}
strcat(message, buf);
sprintf(buf, "Current floor: %d\n", elevator.Current_Floor);
strcat(message, buf);
}
sprintf(buf, "Next floor: %d\n", elevator.Next_Floor);
strcat(message, buf);
if (elevator.Current_Load.weight_int == 0 &&
elevator.Current_Load.weight_dec == 0)
{
sprintf(buf,
"Current load: %d passenger units, 0 weight units\n\n",
elevator.Current_Load.pass_units);
}
else
{
sprintf(buf,
"Current load: %d passenger units, %d.%d weight units\n\n",
elevator.Current_Load.pass_units,
elevator.Current_Load.weight_int,
elevator.Current_Load.weight_dec);
}
strcat(message, buf);
for (i = 0; i < 10; i++)
{
sprintf(buf,
"Floor %d: %d passengers waiting, %d passengers serviced\n",
i + 1,
elevator.Waiting_Passengers[i], elevator.Total_Passengers[i]);
strcat(message, buf);
}
return 0;
}
ssize_t elevator_proc_read(struct file *sp_file, char __user *buf,
size_t size, loff_t *offset)
{
int len = strlen(message);
read_p = !read_p;
if (read_p)
return 0;
printk(KERN_INFO "proc called read\n");
copy_to_user(buf, message, len);
return len;
}
int elevator_proc_release(struct inode *sp_inode, struct file *sp_file)
{
printk(KERN_NOTICE "proc called release\n");
kfree(message);
return 0;
}
/*************************************************************************/
static int elevator_init(void)
{
// all initialization code
stop = false;
STUB_start_elevator = my_start_elevator;
STUB_issue_request = my_issue_request;
STUB_stop_elevator = my_stop_elevator;
printk(KERN_NOTICE "/proc/%s create\n", ENTRY_NAME);
fops.open = elevator_proc_open;
fops.read = elevator_proc_read;
fops.release = elevator_proc_release;
if (!proc_create(ENTRY_NAME, PERMS, NULL, &fops))
{
printk(KERN_WARNING "proc create\n");
remove_proc_entry(ENTRY_NAME, NULL);
return -ENOMEM;
}
thread_init_parameter(&elevator);
if (IS_ERR(elevator.kthread))
{
printk(KERN_WARNING "error spawning thread");
remove_proc_entry(ENTRY_NAME, NULL);
return PTR_ERR(elevator.kthread);
}
return 0;
}
module_init(elevator_init);
static void elevator_exit(void)
{
// all clean up code
kthread_stop(elevator.kthread);
remove_proc_entry(ENTRY_NAME, NULL);
mutex_destroy(&elevator.mutex);
printk(KERN_NOTICE "Removing /proc/%s\n", ENTRY_NAME);
}
module_exit(elevator_exit);
issue_request.c
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/module.h>
/* System call stub */
int (*STUB_issue_request)(int, int, int) = NULL;
EXPORT_SYMBOL(STUB_issue_request);
/* System call wrapper */
asmlinkage int sys_issue_request(int p_type, int start_floor,
int dest_floor)
{
if (STUB_issue_request != NULL)
return STUB_issue_request(p_type, start_floor, dest_floor);
else
return -ENOSYS;
}
start_elevator.c
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/module.h>
/* System call stub */
int (*STUB_start_elevator)(void) = NULL;
EXPORT_SYMBOL(STUB_start_elevator);
/* System call wrapper */
asmlinkage int sys_start_elevator(void)
{
if (STUB_start_elevator != NULL)
return STUB_start_elevator();
else
return -ENOSYS;
}
stop_elevator.c
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/module.h>
/* System call stub */
int (*STUB_stop_elevator)(void) = NULL;
EXPORT_SYMBOL(STUB_stop_elevator);
/* System call wrapper */
asmlinkage int sys_stop_elevator(void)
{
if (STUB_stop_elevator != NULL)
return STUB_stop_elevator();
else
return -ENOSYS;
}
函数是静态的，同一目录下只有一个makefile。所以我的问题是：为什么无法加载 elevator.ko 以及如何修复？
这很简单。靠近顶部的是这些：
WARNING: "STUB_stop_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_issue_request" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_start_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
由于未定义的符号，您的模块将无法加载。一旦在构建时解决了这些问题，模块加载应该会更好地工作。看起来您的 link 只使用了 1 个目标文件。虽然我无权确认，但请尝试调整您的 Makefile 以列出所有目标文件；可能是 obj-m 不完整，应该列出与 obj-y 相同的文件。
如果您在加载模块时 运行 进入其他未定义的符号，并且它们在您的模块外部，则可能存在依赖性问题。对于这种情况，将您的模块复制到 /lib/modules/...... 并尝试使用 modprobe
加载
我正在使用 Linuxmint Cinnamon 19 Ubuntu 18.04，内核版本 4.15.0-20-generic
编译时看到的如下：
make
make -C /lib/modules/`uname -r`/build SUBDIRS=/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator modules
make[1]: Entering directory '/usr/src/linux-headers-4.15.0-20-generic'
CC [M] /home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.o
Building modules, stage 2.
MODPOST 1 modules
WARNING: "STUB_stop_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_issue_request" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_start_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
CC /home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.mod.o
LD [M] /home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko
make[1]: Leaving directory '/usr/src/linux-headers-4.15.0-20-generic'
然后我尝试使用 sudo insmod elevator.ko
安装模块insmod: ERROR: could not insert module elevator.ko: Unknown symbol in module
在日志中看到： 消息 |尾
[ 7.922763] 00:00:00.000285 main Executable: /opt/VBoxGuestAdditions-5.2.4/sbin/VBoxService
00:00:00.000286 main Process ID: 832
00:00:00.000286 main Package type: LINUX_64BITS_GENERIC
[ 7.923912] 00:00:00.001432 main 5.2.4 r119785 started. Verbose level = 0
[ 11.048520] ISO 9660 Extensions: Microsoft Joliet Level 3
[ 11.052008] ISO 9660 Extensions: RRIP_1991A
[ 86.413368] elevator: loading out-of-tree module taints kernel.
[ 86.413422] elevator: Unknown symbol STUB_stop_elevator (err 0)
[ 86.413438] elevator: Unknown symbol STUB_issue_request (err 0)
[ 86.413452] elevator: Unknown symbol STUB_start_elevator (err 0)
生成文件
obj-y := start_elevator.o issue_request.o stop_elevator.o
obj-m := elevator.o
KBUILD_CFLAGS += -fno-pie
PWD := $(shell pwd)
KDIR := /lib/modules/`uname -r`/build
default:
$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
clean:
rm -f *.o *.ko *.mod.* Module.* modules.*
elevator.c
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/linkage.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/uaccess.h>
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Simulates elevator");
#define ENTRY_NAME "elevator"
#define ENTRY_SIZE 700
#define PERMS 0644
#define PARENT NULL
static struct file_operations fops;
static char * message;
static int read_p;
enum States { OFFLINE, IDLE, LOADING, UP, DOWN };
#define MAX_PASSENGER_UNITS 10
#define MAX_WEIGHT_INT 15
#define MAX_WEIGHT_DEC 0
struct thread_parameter
{
enum States Current_State;
int Current_Floor;
int Next_Floor;
int Waiting_Passengers[10];
int Total_Passengers[10];
struct
{
int pass_units;
int weight_int;
int weight_dec;
} Current_Load;
struct list_head list;
int id;
struct task_struct * kthread;
struct mutex mutex;
};
typedef struct
{
int src;
int dst;
int pass_units;
int weight_int;
int weight_dec;
struct list_head list;
} Passenger;
struct thread_parameter elevator;
struct list_head list;
struct list_head elev;
bool stop;
/*************************************************************************/
extern int (*STUB_start_elevator)(void);
int my_start_elevator(void)
{
// start_elevator implementation
int i;
if (elevator.Current_State != OFFLINE)
return 1;
else
{
// try to initialize elevator:
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
elevator.Current_Floor = 1;
elevator.Next_Floor = 1;
elevator.Current_Load.pass_units = 0;
elevator.Current_Load.weight_int = 0;
elevator.Current_Load.weight_dec = 0;
elevator.Current_State = IDLE;
for (i = 0; i < 10; i++)
{
elevator.Waiting_Passengers[i] = 0;
elevator.Total_Passengers[i] = 0;
}
}
mutex_unlock(&elevator.mutex);
if (elevator.Current_State != IDLE)
return -1;
}
return 0;
}
/*************************************************************************/
int load_elev(Passenger * p)
{
struct list_head * temp;
struct list_head * dummy;
bool can_get_on = true;
bool remove = false;
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src != elevator.Current_Floor)
can_get_on = false;
if ((elevator.Current_Load.pass_units + p->pass_units) >
MAX_PASSENGER_UNITS)
can_get_on = false;
if ((elevator.Current_Load.weight_int + p->weight_int) >
MAX_WEIGHT_INT)
can_get_on = false;
if ((elevator.Current_Load.weight_int + p->weight_int) ==
MAX_WEIGHT_INT &&
(elevator.Current_Load.weight_dec == 5 ||
p->weight_dec == 5))
can_get_on = false;
if (p->dst == elevator.Current_Floor)
remove = true;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
if (can_get_on && !remove)
{
if (elevator.Current_Load.pass_units == 0)
INIT_LIST_HEAD(&elev);
elevator.Current_Load.pass_units += p->pass_units;
elevator.Current_Load.weight_int += p->weight_int;
if (elevator.Current_Load.weight_dec == 5 &&
p->weight_dec == 5)
{
elevator.Current_Load.weight_int++;
elevator.Current_Load.weight_dec = 0;
}
else
{
elevator.Current_Load.weight_dec += p->weight_dec;
}
elevator.Waiting_Passengers[elevator.Current_Floor - 1]--;
list_move_tail(temp, &elev);
}
else if (remove)
{
elevator.Waiting_Passengers[elevator.Current_Floor - 1]--;
list_del(temp);
kfree(p);
}
}
mutex_unlock(&elevator.mutex);
return 0;
}
int unload_elev(Passenger * p)
{
// declare some temporary pointers
struct list_head * temp;
struct list_head * dummy;
// use this since you need to change the pointers
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &elev)
{
p = list_entry(temp, Passenger, list);
if (p->dst == elevator.Current_Floor)
{
elevator.Current_Load.pass_units -= p->pass_units;
elevator.Current_Load.weight_int -= p->weight_int;
if (elevator.Current_Load.weight_dec == 0 &&
p->weight_dec == 5)
{
elevator.Current_Load.weight_int--;
elevator.Current_Load.weight_dec = 5;
}
else
{
elevator.Current_Load.weight_dec -=
p->weight_dec;
}
elevator.Total_Passengers[p->src - 1]++;
list_del(temp); // init ver also reinits list
kfree(p); // remember to free allocated data
}
}
}
mutex_unlock(&elevator.mutex);
return 0;
}
/*************************************************************************/
int find_next_floor_up(int current_floor)
{
struct list_head * temp;
Passenger * p;
int next_floor = -1;
int closest_floor = 11; //set this initially
if (elevator.Current_Load.pass_units > 0)
{
list_for_each(temp, &elev)
{
p = list_entry(temp, Passenger, list);
// for each passenger, if their dest is greater
// than current floor
// (i.e. they're going up), and if their dest is less
// than the current closest_floor
if (p->dst > current_floor && p->dst < closest_floor)
{
//make this our next_floor
next_floor = p->dst;
//update closest_floor to this particular passenger's
closest_floor = p->dst;
}
}
list_for_each(temp, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src > current_floor && p->src <= closest_floor &&
p->dst > current_floor)
{
next_floor = p->src;
closest_floor = p->src;
}
}
}
return next_floor;
}
int find_next_floor_down(int current_floor)
{
struct list_head * temp;
Passenger * p;
int next_floor = -1;
int closest_floor = 0;
if (elevator.Current_Load.pass_units > 0)
{
list_for_each(temp, &elev)
{
p = list_entry(temp, Passenger, list);
if (p->dst < current_floor && p->dst > closest_floor)
{
next_floor = p->dst;
closest_floor = p->dst;
}
}
list_for_each(temp, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src < current_floor && p->src >= closest_floor &&
p->dst < current_floor)
{
next_floor = p->src;
closest_floor = p->src;
}
}
}
return next_floor;
}
/*************************************************************************/
extern int (*STUB_issue_request)(int, int, int);
int my_issue_request(int p_type, int start_floor, int dest_floor)
{
// issue_request implementation
Passenger * p = NULL;
struct list_head * temp;
struct list_head * dummy;
if (elevator.Current_State == IDLE)
INIT_LIST_HEAD(&list);
p = kmalloc(sizeof(Passenger), __GFP_RECLAIM);
printk(KERN_NOTICE "MY_ISSUE_REQUEST FUNCTION ENTERED\n");
if (p_type < 1 || p_type > 4 ||
start_floor < 1 || start_floor > 10 ||
dest_floor < 1 || dest_floor > 10)
{
return 1;
}
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
p->src = start_floor;
p->dst = dest_floor;
p->pass_units = 0;
p->weight_int = 0;
p->weight_dec = 0;
switch (p_type)
{
case 1:
{
p->pass_units = 1;
p->weight_int = 1;
p->weight_dec = 0;
break;
}
case 2:
{
p->pass_units = 1;
p->weight_int = 0;
p->weight_dec = 5;
break;
}
case 3:
{
p->pass_units = 2;
p->weight_int = 2;
p->weight_dec = 0;
break;
}
case 4:
{
p->pass_units = 2;
p->weight_int = 3;
p->weight_dec = 0;
break;
}
}
}
mutex_unlock(&elevator.mutex);
if (!stop)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_add_tail(&p->list, &list);
elevator.Waiting_Passengers[p->src - 1]++;
}
mutex_unlock(&elevator.mutex);
if (elevator.Current_State == IDLE)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
if (p->src == elevator.Current_Floor)
{
elevator.Current_State = LOADING;
elevator.Next_Floor = p->dst;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
if (elevator.Current_Floor != p->src)
elevator.Next_Floor = p->src;
if (elevator.Next_Floor > elevator.Current_Floor)
elevator.Current_State = UP;
else if (elevator.Next_Floor < elevator.Current_Floor)
elevator.Current_State = DOWN;
}
mutex_unlock(&elevator.mutex);
}
else if (elevator.Current_State == UP)
{
if (elevator.Current_Load.pass_units == 0)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
elevator.Next_Floor = p->src;
break;
}
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src > elevator.Current_Floor &&
p->src <= elevator.Next_Floor &&
p->dst > elevator.Current_Floor)
{
elevator.Next_Floor = p->src;
}
}
}
mutex_unlock(&elevator.mutex);
}
}
else if (elevator.Current_State == DOWN)
{
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
if (p->src < elevator.Current_Floor &&
p->src >= elevator.Next_Floor &&
p->dst < elevator.Current_Floor)
{
elevator.Next_Floor = p->src;
}
}
}
mutex_unlock(&elevator.mutex);
}
}
return 0;
}
/*************************************************************************/
extern int (*STUB_stop_elevator)(void);
int my_stop_elevator(void)
{
// stop_elevator implementation
/*
deactivates elevator, elevator will
process no more new requests, but will
offload all current passengers
*/
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
stop = true;
}
mutex_unlock(&elevator.mutex);
while (elevator.Current_Load.pass_units != 0){}
if (mutex_lock_interruptible(&elevator.mutex) == 0)
{
elevator.Current_State = OFFLINE;
elevator.Current_Floor = 0;
elevator.Next_Floor = 0;
}
mutex_unlock(&elevator.mutex);
return 0;
}
/*************************************************************************/
int elevator_service(void * data)
{
struct thread_parameter * parm = data;
Passenger * p = NULL;
struct list_head * temp;
struct list_head * dummy;
int i;
bool waiting = false;
printk(KERN_NOTICE "ELEVATOR_SERVICE FUNCTION ENTERED\n");
while (!kthread_should_stop())
{
if (parm->Current_State != OFFLINE && parm->Current_State != IDLE)
{
if (parm->Current_State == LOADING)
{
ssleep(1);
// if there are passengers on elevator, call unload_elev
if (parm->Current_Load.pass_units > 0)
unload_elev(p);
if (!stop)
{
// if stop_elevator hasn't been called, call load_elev
load_elev(p);
}
else
{
// if stop_elevator has been called, delete
// all waiting passengers from list
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
list_del(temp);
kfree(p);
}
}
mutex_unlock(&elevator.mutex);
}
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
for (i = 0; i < 10; i++)
{
if (parm->Waiting_Passengers[i] > 0)
waiting = true;
}
}
mutex_unlock(&elevator.mutex);
// if there are no passengers on elevator
// and no passengers waiting on any floor
if (parm->Current_Load.pass_units == 0 && !waiting)
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_State = IDLE;
}
mutex_unlock(&elevator.mutex);
}
// if there are passengers on the elevator
// and no passengers waiting on any floor
else if (parm->Current_Load.pass_units > 0 && !waiting)
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &elev)
{
p = list_entry(temp, Passenger, list);
parm->Next_Floor = p->dst;
break;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
if (parm->Next_Floor > parm->Current_Floor)
{
if (find_next_floor_up(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_up(
parm->Current_Floor);
}
parm->Current_State = UP;
}
else
{
if (find_next_floor_down(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_down(
parm->Current_Floor);
}
parm->Current_State = DOWN;
}
}
mutex_unlock(&elevator.mutex);
}
// if there are no passengers on the elevator
// and at least one passenger is waiting on a floor
else if (parm->Current_Load.pass_units == 0 && waiting)
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &list)
{
p = list_entry(temp, Passenger, list);
parm->Next_Floor = p->src;
break;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
if (parm->Next_Floor > parm->Current_Floor)
{
if (find_next_floor_up(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_up(
parm->Current_Floor);
}
parm->Current_State = UP;
}
else
{
if (find_next_floor_down(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_down(
parm->Current_Floor);
}
parm->Current_State = DOWN;
}
}
mutex_unlock(&elevator.mutex);
}
// if there is at least one passenger on the elevator
// and at least one passenger waiting on a floor
else
{
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
list_for_each_safe(temp, dummy, &elev)
{
p = list_entry(temp, Passenger, list);
parm->Next_Floor = p->dst;
break;
}
}
mutex_unlock(&elevator.mutex);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
if (parm->Next_Floor > parm->Current_Floor)
{
if (find_next_floor_up(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_up(
parm->Current_Floor);
}
parm->Current_State = UP;
}
else
{
if (find_next_floor_down(
parm->Current_Floor) > 0)
{
parm->Next_Floor =
find_next_floor_down(
parm->Current_Floor);
}
parm->Current_State = DOWN;
}
}
mutex_unlock(&elevator.mutex);
}
}
else if (parm->Current_State == UP)
{
while (parm->Current_Floor != parm->Next_Floor)
{
ssleep(2);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_Floor++;
}
mutex_unlock(&elevator.mutex);
}
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_State = LOADING;
}
mutex_unlock(&elevator.mutex);
}
else // (parm->Current_State == DOWN)
{
while (parm->Current_Floor != parm->Next_Floor)
{
ssleep(2);
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_Floor--;
}
mutex_unlock(&elevator.mutex);
}
if (mutex_lock_interruptible(&parm->mutex) == 0)
{
parm->Current_State = LOADING;
}
mutex_unlock(&elevator.mutex);
}
}
}
return 0;
}
void thread_init_parameter(struct thread_parameter * parm)
{
parm->Current_State = OFFLINE;
mutex_init(&parm->mutex);
parm->kthread = kthread_run(elevator_service, parm,
"elevator in service");
}
/*************************************************************************/
int elevator_proc_open(struct inode *sp_inode, struct file *sp_file)
{
char * buf = kmalloc (sizeof(char) * 100, __GFP_RECLAIM);
int i;
if (buf == NULL)
{
printk(KERN_WARNING "print_time");
return -ENOMEM;
}
printk(KERN_INFO "proc called open\n");
printk(KERN_NOTICE "PROC_OPEN FUNCTION ENTERED\n");
read_p = 1;
message = kmalloc(sizeof(char) * ENTRY_SIZE,
__GFP_RECLAIM | __GFP_IO | __GFP_FS);
if (message == NULL)
{
printk(KERN_WARNING "time_proc_open");
return -ENOMEM;
}
strcpy(message, "");
switch (elevator.Current_State)
{
case 0:
{
sprintf(buf, "State: OFFLINE\n");
break;
}
case 1:
{
sprintf(buf, "State: IDLE\n");
break;
}
case 2:
{
sprintf(buf, "State: LOADING\n");
break;
}
case 3:
{
sprintf(buf, "State: UP\n");
break;
}
case 4:
{
sprintf(buf, "State: DOWN\n");
break;
}
strcat(message, buf);
sprintf(buf, "Current floor: %d\n", elevator.Current_Floor);
strcat(message, buf);
}
sprintf(buf, "Next floor: %d\n", elevator.Next_Floor);
strcat(message, buf);
if (elevator.Current_Load.weight_int == 0 &&
elevator.Current_Load.weight_dec == 0)
{
sprintf(buf,
"Current load: %d passenger units, 0 weight units\n\n",
elevator.Current_Load.pass_units);
}
else
{
sprintf(buf,
"Current load: %d passenger units, %d.%d weight units\n\n",
elevator.Current_Load.pass_units,
elevator.Current_Load.weight_int,
elevator.Current_Load.weight_dec);
}
strcat(message, buf);
for (i = 0; i < 10; i++)
{
sprintf(buf,
"Floor %d: %d passengers waiting, %d passengers serviced\n",
i + 1,
elevator.Waiting_Passengers[i], elevator.Total_Passengers[i]);
strcat(message, buf);
}
return 0;
}
ssize_t elevator_proc_read(struct file *sp_file, char __user *buf,
size_t size, loff_t *offset)
{
int len = strlen(message);
read_p = !read_p;
if (read_p)
return 0;
printk(KERN_INFO "proc called read\n");
copy_to_user(buf, message, len);
return len;
}
int elevator_proc_release(struct inode *sp_inode, struct file *sp_file)
{
printk(KERN_NOTICE "proc called release\n");
kfree(message);
return 0;
}
/*************************************************************************/
static int elevator_init(void)
{
// all initialization code
stop = false;
STUB_start_elevator = my_start_elevator;
STUB_issue_request = my_issue_request;
STUB_stop_elevator = my_stop_elevator;
printk(KERN_NOTICE "/proc/%s create\n", ENTRY_NAME);
fops.open = elevator_proc_open;
fops.read = elevator_proc_read;
fops.release = elevator_proc_release;
if (!proc_create(ENTRY_NAME, PERMS, NULL, &fops))
{
printk(KERN_WARNING "proc create\n");
remove_proc_entry(ENTRY_NAME, NULL);
return -ENOMEM;
}
thread_init_parameter(&elevator);
if (IS_ERR(elevator.kthread))
{
printk(KERN_WARNING "error spawning thread");
remove_proc_entry(ENTRY_NAME, NULL);
return PTR_ERR(elevator.kthread);
}
return 0;
}
module_init(elevator_init);
static void elevator_exit(void)
{
// all clean up code
kthread_stop(elevator.kthread);
remove_proc_entry(ENTRY_NAME, NULL);
mutex_destroy(&elevator.mutex);
printk(KERN_NOTICE "Removing /proc/%s\n", ENTRY_NAME);
}
module_exit(elevator_exit);
issue_request.c
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/module.h>
/* System call stub */
int (*STUB_issue_request)(int, int, int) = NULL;
EXPORT_SYMBOL(STUB_issue_request);
/* System call wrapper */
asmlinkage int sys_issue_request(int p_type, int start_floor,
int dest_floor)
{
if (STUB_issue_request != NULL)
return STUB_issue_request(p_type, start_floor, dest_floor);
else
return -ENOSYS;
}
start_elevator.c
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/module.h>
/* System call stub */
int (*STUB_start_elevator)(void) = NULL;
EXPORT_SYMBOL(STUB_start_elevator);
/* System call wrapper */
asmlinkage int sys_start_elevator(void)
{
if (STUB_start_elevator != NULL)
return STUB_start_elevator();
else
return -ENOSYS;
}
stop_elevator.c
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/module.h>
/* System call stub */
int (*STUB_stop_elevator)(void) = NULL;
EXPORT_SYMBOL(STUB_stop_elevator);
/* System call wrapper */
asmlinkage int sys_stop_elevator(void)
{
if (STUB_stop_elevator != NULL)
return STUB_stop_elevator();
else
return -ENOSYS;
}
函数是静态的，同一目录下只有一个makefile。所以我的问题是：为什么无法加载 elevator.ko 以及如何修复？
这很简单。靠近顶部的是这些：
WARNING: "STUB_stop_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_issue_request" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
WARNING: "STUB_start_elevator" [/home/lukas/Desktop/COP4610-Operating-Systems-Project-2-master/elevator/elevator.ko] undefined!
由于未定义的符号，您的模块将无法加载。一旦在构建时解决了这些问题，模块加载应该会更好地工作。看起来您的 link 只使用了 1 个目标文件。虽然我无权确认，但请尝试调整您的 Makefile 以列出所有目标文件；可能是 obj-m 不完整，应该列出与 obj-y 相同的文件。
如果您在加载模块时 运行 进入其他未定义的符号，并且它们在您的模块外部，则可能存在依赖性问题。对于这种情况，将您的模块复制到 /lib/modules/...... 并尝试使用 modprobe