Procfs open hook bug.

I have done this little patch for the procfs_example.c

diff procfs_example.c kernels/linux-2.4.20/Documentation/DocBook/procfs_example.c 87,91d86
< static int open_qp(struct inode * inode, struct file * file)
< {
< printk("Open my node %p %p \n",inode,file);
< return -EINVAL;
< }
180c175
< foo_file->proc_fops->open=open_qp;
---

And when loading this module. The procfs gets broken. I get EINVAL for open on /proc/meminfo and all other procfs info. Why? Should procfs inodes don't have full filesematics? And it don't help to unload the module.

Strange. And a look in generic.c in fs/proc/

static struct file_operations proc_file_operations = {
llseek: proc_file_lseek,
read: proc_file_read,
write: proc_file_write,
};

Is this saying that we can not have the other fops on procfs inodes? No ioctl,open ?

If you look at other file systems you'll see they swap the file operations pointer