Kernel module with multiple source files compilation problem

Last Attacker · 05-04-2006, 06:17 PM

Hi,
I have a problem with compiling my kernel module.
At this stage its a plain character device that takes input which is piped
through to the /dev/my_device file and when you cat /dev/my_device it returns
the same data.
To have 1 file for my my_device.ko file works fine but if I have multiple
source files it compiles but with warnings stating for example:

Code:

*** Warning: "copyData" [/home/la/compr/dyn_buffer.ko] undefined!
*** Warning: "nullData" [/home/la/compr/dyn_buffer.ko] undefined!
*** Warning: "dynCleanBuffer" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynInitBuffer" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynAddChunk" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynMakeBigBuffer" [/home/la/compr/compr.ko] undefined!

I have compr.c, dyn_buffer.c and utils.c

This is my makefile:
------------------------

Code:

KERNELDIR := /tmp/linux-2.6.10

obj-m += compr_dev.o
compr_dev-objs := dyn_buffer.o utils.o compr.o

.PHONY: all clean

all: 
        $(MAKE) -C $(KERNELDIR) M=`pwd` modules ARCH=um

clean:
        rm -f *.o *.ko *.mod.c

It is for the 2.6.10 UML Linux Kernel.
Here is an abstract view of my source files:

compr.c :
------------

Code:

#include "compr.h"
#include "dyn_buffer.h"

/**     If we ever need to check if we're
 *      using a specific kernel version 
 */
#ifndef KERNEL_VERSION
#define KERNEL_VERSION(a,b,c) ((a) * 65536 + (b) * 256 + (c))
#endif

#include <asm/uaccess.h>        // for put_user
#include <linux/vmalloc.h>  // for vmalloc
#include <linux/proc_fs.h>  // for proc file system
#include <linux/sched.h>    // for sleeping

#define DEVICE_NAME "compr"
#define COMPR_MAJOR 240

//static struct proc_dir_entry *compr_proc_entry;

static struct sDynBuffer compr_buffer;

static struct cdev compr_cdev;

/**     This function is called whenever a process
 *      attempts to open the device file 
 */
static int compr_open(struct inode *inode, struct file *file)
{
        return 0;
}

/**     This function is called when a process closes the
 *      device file.
 */
static int compr_release(struct inode *inode, struct file *file)
{
        return 0;
}

/**     This function is called whenever a process which
 *      have already opened the device file attempts to
 *      read from it.
 */
static ssize_t compr_read( struct file *file,
                           char *buffer,                // The buffer to fill with data
                           size_t length,               // The length of the buffer
                           loff_t *offset)              // Our offset in the file
{
        ...
}

/**     This function is called when somebody tries to write
 *      into our device file.
 */
static ssize_t compr_write( struct file *file,
                            const char *buffer, // The buffer
                            size_t length,              // The length of the buffer
                            loff_t *offset)             // Our offset in the file
{
        ...
}

void __get_user_X(void)
{
}
void __put_user_bad(void)
{
}

int compr_ioctl(struct inode *inode,
                struct file *file,
                unsigned int ioctl_num,         // The number of the ioctl
                unsigned long ioctl_param)      // The parameter to it
{
        return -EINVAL;
}

struct file_operations compr_ops =
{
    .read    = compr_read,
    .write   = compr_write,
    .ioctl   = compr_ioctl,
    .open    = compr_open,
    .release = compr_release,
};

/** Initialize the module */
//static int __init compr_init()
int init_module()
{
        ...
}

/** Cleanup - undid whatever init_module did */
void cleanup_module()
{
...
}

compr.h
----------

Code:

#ifndef _COMPR_H
#define _COMPR_H
        
        #include <linux/init.h>
        #include <linux/kernel.h>
        #include <linux/module.h>
        #include <linux/cdev.h>
        #include <linux/fs.h>   // character device definitions
        #include <linux/ioctl.h>
        #include <linux/types.h>
        
        #define COMPR_GET_STATUS                _IO('M', 0)
        #define COMPR_SET_COMPRESS              _IO('M', 1)
        #define COMPR_SET_DECOMPRESS    _IO('M', 2)
        #define COMPR_SET_ALGO                  _IO('M', 3)
        #define COMPR_GET_ALGO                  _IO('M', 4)
#endif

dyn_buffer.c:
-----------------

Code:

#include "dyn_buffer.h"

int dynInitBuffer(struct sDynBuffer *dbuf)
{
        ...
}

int dynCleanBuffer(struct sDynBuffer *dbuf)
{
        ...
}

//Appends chunk buffers from the speified
//given index.
//Returns the number of chunks created.
static int dynAddNumChunks(struct sDynBuffer *dbuf, int from_index, int 
amount)
{
        ...
}

int dynAddChunk(struct sDynBuffer *dbuf, char *buf, size_t size)
{
        ...
}

char *dynMakeBigBuffer(struct sDynBuffer *dbuf, size_t *size)
{
        ...
}

dyn_buffer.h:
----------------

Code:

#ifndef _DYNAMIC_BUFFER_H
#define _DYNAMIC_BUFFER_H
        
        #include <linux/types.h>
        #include <linux/vmalloc.h>
        
        #include "utils.h"
        
        #define CHUNK_SIZE      4096
        #define INIT_SIZE       10
        
        //Error symbols
        #define ERROR_MEM       1       /** Couldn't allocate memory for buffer */
        
        /**     A structure holding valuable
         *      information on a dynamic buffer.<br>
         *      <b>NOTE :</b> Do not alter anything
         *      in this structure!
         */
        struct sDynBuffer
        {
                size_t actual_size;     /** Size of data in dynamic buffer */
                int size;                       /** Amount of data chunks */
                int index;                      /** Current chunk index */
                int offset;                     /** Current place in chunk */
                char **data;            /** Array of chunk buffers */
        };
        
        #define DYN_BUFFER_SIZE(BUFFER) (BUFFER.actual_size)
        
        int dynInitBuffer(struct sDynBuffer *dbuf);
        int dynCleanBuffer(struct sDynBuffer *dbuf);
        int dynAddChunk(struct sDynBuffer *dbuf, char *buf, size_t size);
        char *dynMakeBigBuffer(struct sDynBuffer *dbuf, size_t *size);
        
#endif //_DYNAMIC_BUFFER_H

utils.h:
--------

Code:

#ifndef _UTILS_H
#define _UTILS_H
        
        #include <linux/types.h>
        
        void copyData(const char *from_data, char *to_data, size_t len);
        void nullData(char *data, size_t len);
        
#endif //_UTILS_H

utils.c:
--------

Code:

#include "utils.h"

void copyData(const char *from_data, char *to_data, size_t len)
{
        ...
}

void nullData(char *data, size_t len)
{
        ...
}

I hope anyone can help me with this!
Thanks

madluther · 05-04-2006, 06:44 PM

Looks like the problem is in your Makefile
change this

Code:

obj-m += compr_dev.o
compr_dev-objs := dyn_buffer.o utils.o compr.o

to

Code:

obj-m := compr_dev.o
compr_dev-objs := dyn_buffer.o utils.o compr.o

and hopefully it should build

HTH

Mad.

Last Attacker · 05-05-2006, 12:58 AM

Tried that about a couple of times.
Sorry doesn't work.

Last Attacker · 05-05-2006, 04:30 AM

I thoaght it might be a good idea to submit a more detailed report on what the compiler gave me:

- non-verbosed -

Code:

make -C /tmp/linux-2.6.10 M=`pwd` modules ARCH=um
make[1]: Entering directory `/tmp/linux-2.6.10'
  CC [M]  /home/la/compr/compr.o
In file included from /home/la/compr/compr.h:16,
                 from /home/la/compr/compr.c:9:
include/linux/cdev.h:24: warning: ‘struct inode’ declared inside parameter list
include/linux/cdev.h:24: warning: its scope is only this definition or declaration, which is probably not what you want
  CC [M]  /home/la/compr/dyn_buffer.o
  CC [M]  /home/la/compr/utils.o
  LD [M]  /home/la/compr/compr_dev.o
  Building modules, stage 2.
  MODPOST
*** Warning: "copyData" [/home/la/compr/dyn_buffer.ko] undefined!
*** Warning: "nullData" [/home/la/compr/dyn_buffer.ko] undefined!
*** Warning: "dynCleanBuffer" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynInitBuffer" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynAddChunk" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynMakeBigBuffer" [/home/la/compr/compr.ko] undefined!
  CC      /home/la/compr/compr.mod.o
  LD [M]  /home/la/compr/compr.ko
  CC      /home/la/compr/compr_dev.mod.o
  LD [M]  /home/la/compr/compr_dev.ko
  CC      /home/la/compr/dyn_buffer.mod.o
  LD [M]  /home/la/compr/dyn_buffer.ko
make[1]: Leaving directory `/tmp/linux-2.6.10'

- verbosed -

Code:

make -C /tmp/linux-2.6.10 M=`pwd` modules ARCH=um
make[1]: Entering directory `/tmp/linux-2.6.10'
mkdir -p /home/la/compr/.tmp_versions
make -f scripts/Makefile.build obj=/home/la/compr
  gcc -Wp,-MD,/home/la/compr/.compr.o.d -nostdinc -iwithprefix include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2     -fomit-frame-pointer -U__i386__ -Ui386  -D__arch_um__ -DSUBARCH=\"i386\" -D_LARGEFILE64_SOURCE -Iarch/um/include -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask -I/tmp/linux-2.6.10/arch/um/kernel/skas/include -fno-unit-at-a-time -Wdeclaration-after-statement   -DMODULE -DKBUILD_BASENAME=compr -DKBUILD_MODNAME=compr_dev -c -o /home/la/compr/.tmp_compr.o /home/la/compr/compr.c
In file included from /home/la/compr/compr.h:16,
                 from /home/la/compr/compr.c:9:
include/linux/cdev.h:24: warning: ‘struct inode’ declared inside parameter list
include/linux/cdev.h:24: warning: its scope is only this definition or declaration, which is probably not what you want
  gcc -Wp,-MD,/home/la/compr/.dyn_buffer.o.d -nostdinc -iwithprefix include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2     -fomit-frame-pointer -U__i386__ -Ui386  -D__arch_um__ -DSUBARCH=\"i386\" -D_LARGEFILE64_SOURCE -Iarch/um/include -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask -I/tmp/linux-2.6.10/arch/um/kernel/skas/include -fno-unit-at-a-time -Wdeclaration-after-statement   -DMODULE -DKBUILD_BASENAME=dyn_buffer -DKBUILD_MODNAME=compr_dev -c -o /home/la/compr/.tmp_dyn_buffer.o /home/la/compr/dyn_buffer.c
  gcc -Wp,-MD,/home/la/compr/.utils.o.d -nostdinc -iwithprefix include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2     -fomit-frame-pointer -U__i386__ -Ui386  -D__arch_um__ -DSUBARCH=\"i386\" -D_LARGEFILE64_SOURCE -Iarch/um/include -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask -I/tmp/linux-2.6.10/arch/um/kernel/skas/include -fno-unit-at-a-time -Wdeclaration-after-statement   -DMODULE -DKBUILD_BASENAME=utils -DKBUILD_MODNAME=compr_dev -c -o /home/la/compr/.tmp_utils.o /home/la/compr/utils.c
  ld   -r -o /home/la/compr/compr_dev.o /home/la/compr/compr.o /home/la/compr/dyn_buffer.o /home/la/compr/utils.o
  Building modules, stage 2.
make -rR -f /tmp/linux-2.6.10/scripts/Makefile.modpost
  scripts/mod/modpost -m -a -i /tmp/linux-2.6.10/Module.symvers vmlinux /home/la/compr/compr.o /home/la/compr/compr_dev.o /home/la/compr/dyn_buffer.o
*** Warning: "copyData" [/home/la/compr/dyn_buffer.ko] undefined!
*** Warning: "nullData" [/home/la/compr/dyn_buffer.ko] undefined!
*** Warning: "dynCleanBuffer" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynInitBuffer" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynAddChunk" [/home/la/compr/compr.ko] undefined!
*** Warning: "dynMakeBigBuffer" [/home/la/compr/compr.ko] undefined!
  gcc -Wp,-MD,/home/la/compr/.compr.mod.o.d -nostdinc -iwithprefix include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2     -fomit-frame-pointer -U__i386__ -Ui386  -D__arch_um__ -DSUBARCH=\"i386\" -D_LARGEFILE64_SOURCE -Iarch/um/include -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask -I/tmp/linux-2.6.10/arch/um/kernel/skas/include -fno-unit-at-a-time -Wdeclaration-after-statement    -DKBUILD_BASENAME=compr -DKBUILD_MODNAME=compr -DMODULE -c -o /home/la/compr/compr.mod.o /home/la/compr/compr.mod.c
  ld  -r -o /home/la/compr/compr.ko /home/la/compr/compr.o /home/la/compr/compr.mod.o
  gcc -Wp,-MD,/home/la/compr/.compr_dev.mod.o.d -nostdinc -iwithprefix include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2     -fomit-frame-pointer -U__i386__ -Ui386  -D__arch_um__ -DSUBARCH=\"i386\" -D_LARGEFILE64_SOURCE -Iarch/um/include -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask -I/tmp/linux-2.6.10/arch/um/kernel/skas/include -fno-unit-at-a-time -Wdeclaration-after-statement    -DKBUILD_BASENAME=compr_dev -DKBUILD_MODNAME=compr_dev -DMODULE -c -o /home/la/compr/compr_dev.mod.o /home/la/compr/compr_dev.mod.c
  ld  -r -o /home/la/compr/compr_dev.ko /home/la/compr/compr_dev.o /home/la/compr/compr_dev.mod.o
  gcc -Wp,-MD,/home/la/compr/.dyn_buffer.mod.o.d -nostdinc -iwithprefix include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2     -fomit-frame-pointer -U__i386__ -Ui386  -D__arch_um__ -DSUBARCH=\"i386\" -D_LARGEFILE64_SOURCE -Iarch/um/include -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask -I/tmp/linux-2.6.10/arch/um/kernel/skas/include -fno-unit-at-a-time -Wdeclaration-after-statement    -DKBUILD_BASENAME=dyn_buffer -DKBUILD_MODNAME=dyn_buffer -DMODULE -c -o /home/la/compr/dyn_buffer.mod.o /home/la/compr/dyn_buffer.mod.c
  ld  -r -o /home/la/compr/dyn_buffer.ko /home/la/compr/dyn_buffer.o /home/la/compr/dyn_buffer.mod.o
make[1]: Leaving directory `/tmp/linux-2.6.10'

See how it created multiple .ko files, where it is supposed to only make 1?

madluther · 05-05-2006, 07:59 AM

Strange, I have cut 'n' pasted all your sources into files on my pc, added some dummy return statements in the obvious places and it builds just fine. I suspect the problem is elsewhere.

This is what I get when building.

Code:

madluther@pc2:~/lkp/lq$ make V=1
make -C /lib/modules/2.6.13.2/build M=`pwd` modules ARCH=i386
make[1]: Entering directory `/usr/src/linux-2.6.13'
mkdir -p /home/madluther/lkp/lq/.tmp_versions
make -f scripts/Makefile.build obj=/home/madluther/lkp/lq
  gcc -m32 -Wp,-MD,/home/madluther/lkp/lq/.dyn_buffer.o.d  -nostdinc -isystem /usr/lib/gcc/i686-pc-linux-gnu/3.4.1/include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -ffreestanding -O2     -fomit-frame-pointer -pipe -msoft-float -mpreferred-stack-boundary=2 -fno-unit-at-a-time -march=i686 -mtune=pentium4 -Iinclude/asm-i386/mach-default -Wdeclaration-after-statement    -DMODULE -DKBUILD_BASENAME=dyn_buffer -DKBUILD_MODNAME=compr_dev -c -o /home/madluther/lkp/lq/dyn_buffer.o /home/madluther/lkp/lq/dyn_buffer.c
/home/madluther/lkp/lq/dyn_buffer.c: In function `dynMakeBigBuffer':
/home/madluther/lkp/lq/dyn_buffer.c:28: warning: control reaches end of non-void function
/home/madluther/lkp/lq/dyn_buffer.c: At top level:
/home/madluther/lkp/lq/dyn_buffer.c:18: warning: 'dynAddNumChunks' defined but not used
  gcc -m32 -Wp,-MD,/home/madluther/lkp/lq/.utils.o.d  -nostdinc -isystem /usr/lib/gcc/i686-pc-linux-gnu/3.4.1/include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -ffreestanding -O2     -fomit-frame-pointer -pipe -msoft-float -mpreferred-stack-boundary=2 -fno-unit-at-a-time -march=i686 -mtune=pentium4 -Iinclude/asm-i386/mach-default -Wdeclaration-after-statement    -DMODULE -DKBUILD_BASENAME=utils -DKBUILD_MODNAME=compr_dev -c -o /home/madluther/lkp/lq/utils.o /home/madluther/lkp/lq/utils.c
  gcc -m32 -Wp,-MD,/home/madluther/lkp/lq/.compr.o.d  -nostdinc -isystem /usr/lib/gcc/i686-pc-linux-gnu/3.4.1/include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -ffreestanding -O2     -fomit-frame-pointer -pipe -msoft-float -mpreferred-stack-boundary=2 -fno-unit-at-a-time -march=i686 -mtune=pentium4 -Iinclude/asm-i386/mach-default -Wdeclaration-after-statement    -DMODULE -DKBUILD_BASENAME=compr -DKBUILD_MODNAME=compr_dev -c -o /home/madluther/lkp/lq/compr.o /home/madluther/lkp/lq/compr.c
In file included from /home/madluther/lkp/lq/compr.h:7,
                 from /home/madluther/lkp/lq/compr.c:1:
include/linux/cdev.h:24: warning: "struct inode" declared inside parameter list
include/linux/cdev.h:24: warning: its scope is only this definition or declaration, which is probably not what you want
/home/madluther/lkp/lq/compr.c: In function `init_module':
/home/madluther/lkp/lq/compr.c:93: warning: control reaches end of non-void function
/home/madluther/lkp/lq/compr.c: At top level:
/home/madluther/lkp/lq/compr.c:21: warning: 'compr_buffer' defined but not used
/home/madluther/lkp/lq/compr.c:23: warning: 'compr_cdev' defined but not used
  ld -m elf_i386 -m elf_i386  -r -o /home/madluther/lkp/lq/compr_dev.o /home/madluther/lkp/lq/dyn_buffer.o /home/madluther/lkp/lq/utils.o /home/madluther/lkp/lq/compr.o
  Building modules, stage 2.
make -rR -f /usr/src/linux-2.6.13/scripts/Makefile.modpost
  scripts/mod/modpost   -i /usr/src/linux-2.6.13/Module.symvers vmlinux /home/madluther/lkp/lq/compr_dev.o
  gcc -m32 -Wp,-MD,/home/madluther/lkp/lq/.compr_dev.mod.o.d  -nostdinc -isystem /usr/lib/gcc/i686-pc-linux-gnu/3.4.1/include -D__KERNEL__ -Iinclude  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -ffreestanding -O2     -fomit-frame-pointer -pipe -msoft-float -mpreferred-stack-boundary=2 -fno-unit-at-a-time -march=i686 -mtune=pentium4 -Iinclude/asm-i386/mach-default -Wdeclaration-after-statement     -DKBUILD_BASENAME=compr_dev -DKBUILD_MODNAME=compr_dev -DMODULE -c -o /home/madluther/lkp/lq/compr_dev.mod.o /home/madluther/lkp/lq/compr_dev.mod.c
  ld -m elf_i386 -m elf_i386 -r -o /home/madluther/lkp/lq/compr_dev.ko /home/madluther/lkp/lq/compr_dev.o /home/madluther/lkp/lq/compr_dev.mod.o
make[1]: Leaving directory `/usr/src/linux-2.6.13'

I changed ARCH to i386, but everything else is the same.

HTH

Mad.

Last Attacker · 05-05-2006, 08:33 AM

Could it be a bad linux kernel or did I do something wrong in one of the implementation phases?
Maybe I'll try to put on the 2.6.16 kernel since that has worked before with UML but I removed it for some reason I couldn't remember.
Like I said, I have the 2.6.10 kernel for UML and 2.6.13-15 for my default SuSE.
Strange thing is that SuSE 10's release kernel doesn't want to compile into UML.

Last Attacker · 05-06-2006, 08:16 AM

I have compiled it with my ordinary 2.6.13-15 kernel that comes with SuSE 10 but still gives me the *** warning messages.
Atleast I didn't have to add the ARCH=um in my makefile.

Last Attacker · 05-06-2006, 09:10 AM

I finally got it with the help of Maxim at the #kernelnewbies IRC channel.
All I had to do was issue a "make -C <path to linux src> M=`pwd` clean" first

Man, another small stone that made it look like a mountain to cross!
Trust me, when you get to a problem that looks bad ... step back and check all the small stuff because the chances are good that it is just 1 thing you've missed.

Thanks to all who've helped me with this!