Databases
StackOverflow2013
Postsdbo
POLinux Device Driver: Symbol "memcpy" not found
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POLinux Device Driver: Symbol "memcpy" not found
    primarykey
    data
    text
    <p>I'm trying to write a Linux device driver. I've got it to work really well, until I tried to use "memcpy". I don't even get a compiler error, when I "make" it just warns me: </p> <p><code>WARNING: "memcpy" [/root/homedir/sv/main.ko] undefined!</code></p> <p>OK and when I try to load via insmod, I get on the console:</p> <p><code>insmod: error inserting './main.ko': -1 Unknown symbol in module</code></p> <p>and on dmesg:</p> <p><code>main: Unknown symbol memcpy (err 0)</code></p> <p>I include the following:</p> <pre><code>#include &lt;linux/module.h&gt; #include &lt;linux/moduleparam.h&gt; #include &lt;linux/init.h&gt; #include &lt;linux/kernel.h&gt; /* printk() */ #include &lt;linux/slab.h&gt; /* kmalloc() */ #include &lt;linux/fs.h&gt; /* everything... */ #include &lt;linux/errno.h&gt; /* error codes */ #include &lt;linux/types.h&gt; /* size_t */ #include &lt;linux/fcntl.h&gt; /* O_ACCMODE */ #include &lt;linux/cdev.h&gt; #include &lt;asm/system.h&gt; /* cli(), *_flags */ #include &lt;asm/uaccess.h&gt; /* copy_*_user */ </code></pre> <p>The function using memcpy:</p> <pre><code>static int dc_copy_to_user(char __user *buf, size_t count, loff_t *f_pos, struct sv_data_dev *dev) { char data[MAX_KEYLEN]; size_t i = 0; /* Copy the bulk as long as there are 10 more bytes to copy */ while (i &lt; (count + MAX_KEYLEN)) { memcpy(data, &amp;dev-&gt;data[*f_pos + i], MAX_KEYLEN); ec_block(dev-&gt;key, data, MAX_KEYLEN); if (copy_to_user(&amp;buf[i], data, MAX_KEYLEN)) { return -EFAULT; } i += MAX_KEYLEN; } return 0; } </code></pre> <p>Could someone help me? I thought the thing was in linux/string.h, but I get the error just the same. I'm using kernel 2.6.37-rc1 (I'm doing in in user-mode-linux, which works only since 2.6.37-rc1). Any help is greatly appreciated. </p> <pre><code># Context dependent makefile that can be called directly and will invoke itself # through the kernel module building system. KERNELDIR=/usr/src/linux ifneq ($(KERNELRELEASE),) EXTRA_CFLAGS+=-I $(PWD) -ARCH=um obj-m := main.o else KERNELDIR ?= /lib/modules/$(shell uname -r)/build PWD = $(shell pwd) all: $(MAKE) V=1 ARCH=um -C $(KERNELDIR) M=$(PWD) modules clean: rm -rf Module.symvers .*.cmd *.ko .*.o *.o *.mod.c .tmp_versions *.order endif </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USFred Foo
    1. USHinton
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POLinux Device Driver: Symbol "memcpy" not found
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POLinux Device Driver: Symbol "memcpy" not found
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POLinux Device Driver: Symbol "memcpy" not found
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI think you are missing `#include <stdio.h>`... obviously unless one of the linux headers already includes it :p
      singulars
      1. POLinux Device Driver: Symbol "memcpy" not found
      1. USMachinarius
    2. CO@Drknezz it doesn't and that's because you can't use it. The kernel isn't a hosted environment and there is no stdio. And the code doesn't include stdio so there's also no *reason* to include it.
      singulars
      1. POLinux Device Driver: Symbol "memcpy" not found
      1. UShobbs
    3. CO@Hinton that's a linking error, not a compilation error. How are you building your module?
      singulars
      1. POLinux Device Driver: Symbol "memcpy" not found
      1. UShobbs
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload