invalid drv data in show attribute

["Czerwacki, Eial" <eial.czerwacki@xxxxxxx>]

Greetings,

while working on a driver, I've found a bug that I'm unable to understand.
I assume that I'm doing something wrong. here is my reduced c file:
#include <linux/string.h>
#include <linux/module.h>
#include <linux/pci.h>

/* modules info */
#define DEVICE_NAME "vSMP"
#define DRIVER_LICENSE "GPL v2"
#define DRIVER_AUTHOR "Eial Czerwacki <eial.czerwacki@xxxxxxx>"
#define DRIVER_DESC "vSMP hypervisor driver"
#define DRIVER_VERSION "0.1"

#define PCI_DEVICE_ID_SAP_FLX_VSMP_CTL 0x1011

#define ROOT_SYFS_FOLDER "vsmp"
#define DEVICE_ATTR_NAME(_name_) &dev_attr_##_name_ .attr

#ifndef sysfs_emit
#define sysfs_emit sprintf
#endif // sysfs_emit

MODULE_LICENSE(DRIVER_LICENSE);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);

#define MAX_LABEL_LEN 81

struct data {
	char version[MAX_LABEL_LEN];
	struct pci_dev *pdev;
	struct kobject *kobj;
};

static ssize_t version_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct data *d = dev_get_drvdata(dev);

 	return sysfs_emit(buf, "%s\n", d->version);
}

DEVICE_ATTR_RO(version);

static int populate_version(struct data *d)
{
	int ret_val;

	snprintf(d->version, sizeof(d->version) - 1,
		 "%u.%u.%u.%u", 1,2,3,4);

	ret_val = sysfs_add_file_to_group(d->kobj, DEVICE_ATTR_NAME(version), NULL);
	if (ret_val) {
		dev_err(&d->pdev->dev, "Failed to create version entry, error (%d)\n",
			ret_val);
		return -EINVAL;
	}
	dev_info(&d->pdev->dev, "version is %s\n", d->version);

	return ret_val;
}

static const struct pci_device_id vsmp_pci_table[] = {
	{ PCI_VDEVICE(SCALEMP, PCI_DEVICE_ID_SAP_FLX_VSMP_CTL), 0, },
	{ 0, }, /* terminate list */
};

static int vsmp_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
{
	struct data *d;
	int ret_val = 0;

	d = devm_kzalloc(&pci->dev, sizeof(*d), GFP_KERNEL);
	if (IS_ERR(d))
		return PTR_ERR(d);

	d->pdev = pci;
	pci_set_drvdata(pci, d);
	d->kobj = kobject_create_and_add(ROOT_SYFS_FOLDER, &d->pdev->dev.kobj);
	if (!d->kobj) {
		kfree(d);
		dev_err(&d->pdev->dev, "Failed to create vSMP sysfs entry.\n");

		return -EINVAL;
	}

	ret_val = sysfs_create_link(hypervisor_kobj, d->kobj, ROOT_SYFS_FOLDER);
	if (ret_val) {
		kobject_del(d->kobj);
		kfree(d);
		dev_err(&d->pdev->dev, "Failed to link obj to hypervisor, error (%d)\n", ret_val);

		return ret_val;
	}

	populate_version(d);

	dev_info(&d->pdev->dev, "Driver up and running\n");
	return ret_val;
}

static void vsmp_pci_remove(struct pci_dev *pci)
{
	struct data *d = pci_get_drvdata(pci);

	kobject_del(d->kobj);
	sysfs_remove_link(hypervisor_kobj, ROOT_SYFS_FOLDER);
	kfree(d);
}

static struct pci_driver vsmp_pci_driver = {
	.name		= DEVICE_NAME,
	.id_table	= vsmp_pci_table,
	.probe		= vsmp_pci_probe,
	.remove		= vsmp_pci_remove,
};

module_pci_driver(vsmp_pci_driver);

it compiles well (the kernel I use doesn't have sysfs_emit so I had to improvise) and loads well but when I cat the version file, I don't get valid data. even with printks.
printing the addresses of d from the init and the d inside the show attr func returns different addresses.
can anyone help me understand what I'm doing wrong?

Thanks,

Eial