内核模块无法链接-找不到symbol mutex_lock_nested

Question

我正在尝试为x64上的Linux3.10.45构建一个内核模块(硬件的压力测试工具)。

我使用和函数mutex_init、mutex_lock、mutex_unlock和mutex_destroy添加了互斥。

构建模块时没有产生任何错误或警告，但是当使用'insmod‘加载时，dmesg中会出现错误消息：

[76603.744551] tryBlk: Unknown symbol mutex_lock_nested (err 0)
[76603.744574] tryBlk: Unknown symbol mutex_destroy (err 0)

我发现一个提示，对于‘未知符号’，添加MODULE_LICENSE("GPL v2")行有时会有帮助。

没什么区别。

查看linux/mutex.h，我发现只有在定义了符号CONFIG_DEBUG_LOCK_ALLOC的情况下，mutex_lock才会定义为mutex_lock_nested。(我不记得摸过它。

这有什么问题吗？我是否需要手动向我的模块添加其他东西，以使其使用此调试功能进行构建？

已尝试更改包含文件和顺序。没什么区别。

系统正在运行Debian-7 'Wheezy‘x64，内核改为3.10.45。

使用互斥锁的文件：

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
#include "ring.h"




struct RingBuf
{
    unsigned char *buffer;
    unsigned int size;
    unsigned int inp,outp;
    struct mutex mtx;
};



static int _bytesavail(struct RingBuf *self);
static int _spaceavail(struct RingBuf *self);


struct RingBuf *RingBuf_init(unsigned int size)
{
  struct RingBuf *self;
    if( size<16 )size=16;
    if( size>0x10000000u )return 0;
    if( size & (size-1) )
    {
      unsigned int ns;
        // is not a power of 2.
        size = size<<1;
        while(1)
        {
            ns=size&(size-1);
            if(!ns)break;
            size=ns;
        }
    }
    self = (struct RingBuf*)vmalloc(sizeof(*self)+size);
    memset( self , 0 , sizeof(*self) );
    self->buffer = (unsigned char*)(self+1);
    self->size = size;
    self->inp = 0;
    self->outp = 0;
    mutex_init( &(self->mtx) );
    return self;
}

void RingBuf_uninit(struct RingBuf *self)
{
    if(!self)return;
    mutex_lock( &(self->mtx) );
    mutex_destroy( &(self->mtx) );
    memset( self , 0xFE , sizeof(*self) );
    vfree(self);
}

int RingBuf_add(struct RingBuf *self,const void *data,int num)
{
  int cpy;
    if(num<=0)return 0;
    mutex_lock( &(self->mtx) );
    // check amount to copy
    cpy = _spaceavail(self);
    if(cpy>num)cpy=num;
    // one part or split
    if( self->inp+cpy <= self->size )
    {
        // one chunk
        memcpy( self->buffer+self->inp , data , cpy );
    }else{
      int p1 = (self->size-self->inp);
        // wrapped
        memcpy( self->buffer+self->inp , data , p1 );
        memcpy( self->buffer , ((const unsigned char*)data)+p1 , cpy-p1 );
    }
    self->inp = (self->inp+cpy) & (self->size-1) ;
    mutex_unlock( &(self->mtx) );
    return cpy;
}

int RingBuf_get(struct RingBuf *self,void *data,int num)
{
  int cpy;
    if(num<=0)return 0;
    mutex_lock( &(self->mtx) );
    // check amount to copy
    cpy = _bytesavail(self);
    if(cpy>num)cpy=num;
    // one part or split
    if( self->outp+cpy <= self->size )
    {
        // one chunk
        memcpy( data , self->buffer+self->outp , cpy );
    }else{
      int p1 = (self->size-self->outp);
        // wrapped
        memcpy( data , self->buffer+self->outp , p1 );
        memcpy( ((unsigned char*)data)+p1 , self->buffer , cpy-p1 );
    }
    self->outp = (self->outp+cpy) & (self->size-1) ;
    mutex_unlock( &(self->mtx) );
    return cpy;
}

int RingBuf_get_user(struct RingBuf *self,void __user *data,int num)
{
  int cpy;
  int ret;
    if(num<=0)return 0;
    mutex_lock( &(self->mtx) );
    // check amount to copy
    cpy = _bytesavail(self);
    if(cpy>num)cpy=num;
    // one part or split
    if( self->outp+cpy <= self->size )
    {
        // one chunk
        ret = copy_to_user( data , self->buffer+self->outp , cpy );
    }else{
      int p1 = (self->size-self->outp);
        // wrapped
        ret = copy_to_user( data , self->buffer+self->outp , p1 );
        if(!ret)
            ret = copy_to_user( ((unsigned char*)data)+p1 , self->buffer , cpy-p1 );
    }
    if(ret)return -1;
    self->outp = (self->outp+cpy) & (self->size-1) ;
    mutex_unlock( &(self->mtx) );
    return cpy;
}

int RingBuf_numBytes(struct RingBuf *self)
{
  int result;
    mutex_lock( &(self->mtx) );
    result = _bytesavail(self);
    mutex_unlock( &(self->mtx) );
    return result;
}

static int _bytesavail(struct RingBuf *self)
{
    return (self->inp-self->outp)&(self->size-1);
}

static int _spaceavail(struct RingBuf *self)
{
    return (self->outp-self->inp-1)&(self->size-1);
}

Answer 1

我只是发现它在某种程度上取决于我是如何构建模块的。

互斥锁的东西在另一个源文件中(上面列出的那个)。当我将其剪切/粘贴到模块的第一个主源代码中时，它可以正常工作。

因此，如何创建跨越多个源文件的模块是一个问题。

我的(不能正常工作的) Makefile是：

obj-m += tryBlk.o
tryBlk-objs := ring.o

它在没有警告的情况下构建，但是没有正确地找到'ring.o‘文件中的内核符号。

===============================================

现在我也解决了另一个问题。要共享，makefile是错误的。

下面是更好的makefile：

obj-m := tryBlk.o
tryBlk-objs := tryBlk_main.o ring.o

我还需要将主要部分从'tryBlk.c‘重命名为'tryBlk_main.c’。