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下次插入模块时会打印内核模块退出消息

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下次插入模块时会打印内核模块退出消息

我已经编写了简单的内核模块来打印 Hello 内核消息。

我的模块.c

#include <linux/module.h>
#include <linux/init.h>

/* Meta Information */
MODULE_LICENSE("GPL");
MODULE_AUTHOR("BHAGWAT");
MODULE_DESCRIPTION("A HELLO WORLD MODULE");

/*this function is called when module is loaded into the kernel*/

static int __init ModuleInit(void)
{
    printk("Hello, kernel!\n");
    return 0;
}

/*this function is called when module is removed from kernel*/
static void __exit ModuleExit(void)
{
    printk("Goodbye, kernel");
}

module_init(ModuleInit);
module_exit(ModuleExit);

Makefile

obj-m += my_module.o

all:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

当我插入模块时，内核日志中会打印消息，但当我移除模块时，不会打印消息。当我再次插入模块时，会打印两个消息，一个是上次模块退出的消息，另一个是模块加载的消息。为什么当我插入模块时模块退出消息会打印，但移除模块时不会打印？

bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ sudo insmod my_module.ko
bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ dmesg | tail
[   24.595403] rfkill: input handler enabled
[   30.244336] rfkill: input handler disabled
[  145.426767] my_module: module verification failed: signature and/or required key missing - tainting kernel
[  145.427022] Hello, kernel!
[  217.026559] Goodbye, kernel
[  498.489388] Hello, kernel!
[  524.139613] Goodbye, kernel
[  528.270128] Hello, kernel!
[  577.360611] Goodbye, kernel
[  587.700237] Hello, kernel!
bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ sudo rmmod my_module 
bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ dmesg | tail
[   24.595403] rfkill: input handler enabled
[   30.244336] rfkill: input handler disabled
[  145.426767] my_module: module verification failed: signature and/or required key missing - tainting kernel
[  145.427022] Hello, kernel!
[  217.026559] Goodbye, kernel
[  498.489388] Hello, kernel!
[  524.139613] Goodbye, kernel
[  528.270128] Hello, kernel!
[  577.360611] Goodbye, kernel
[  587.700237] Hello, kernel!
bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ sudo insmod my_module.ko
bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ dmesg | tail
[  145.426767] my_module: module verification failed: signature and/or required key missing - tainting kernel
[  145.427022] Hello, kernel!
[  217.026559] Goodbye, kernel
[  498.489388] Hello, kernel!
[  524.139613] Goodbye, kernel
[  528.270128] Hello, kernel!
[  577.360611] Goodbye, kernel
[  587.700237] Hello, kernel!
[  667.900373] Goodbye, kernel
[  676.245356] Hello, kernel!
bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ sudo rmmod my_module 
bhagwat@bhagwat:~/bhagwatws/Personal/device_driver$ dmesg | tail
[  145.426767] my_module: module verification failed: signature and/or required key missing - tainting kernel
[  145.427022] Hello, kernel!
[  217.026559] Goodbye, kernel
[  498.489388] Hello, kernel!
[  524.139613] Goodbye, kernel
[  528.270128] Hello, kernel!
[  577.360611] Goodbye, kernel
[  587.700237] Hello, kernel!
[  667.900373] Goodbye, kernel
[  676.245356] Hello, kernel!

答案1

在退出模块 printk("Goodbye, kernel\n"); 的 printk 语句中使用 '\n'

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