我正在尝试为 x64 上的 Linux 3.10.45 构建内核模块(硬件压力测试工具)。到目前为止,它似乎工作正常,直到添加一个互斥体。
我使用 mutex_init、mutex_lock、mutex_unlock 和 mutex_destroy 添加了互斥锁。
构建模块没有产生错误或警告,但是当使用“insmod”加载时,dmesg 中有错误消息:
[76603.744551] tryBlk: Unknown symbol mutex_lock_nested (err 0)
[76603.744574] tryBlk: Unknown symbol mutex_destroy (err 0)
我发现使用“未知符号”的提示,有时添加 MODULE_LICENSE("GPL v2") 行会有所帮助。
没有不同。
查看 linux/mutex.h,我发现 mutex_lock 只有在定义了符号 CONFIG_DEBUG_LOCK_ALLOC 时才会定义为 mutex_lock_nested。检查这一点,它似乎是在我的 .config 中定义的。(不记得碰过它。它基本上只是来自 kernel.org 的内核,已构建)。
这有问题吗?我是否需要手动向我的模块添加其他内容才能使用此调试功能构建它?
试图更改包含文件和序列。没有不同。
系统正在运行 Debian-7 'Wheezy' x64,内核更改为 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);
}