Mailing List Archive

"be->mode" is obtained from xenbus_read(), which does a kmalloc() for
the message body. The short string is never released, so do it along
with freeing "be" itself, and make sure the string isn't kept when
backend_changed() doesn't complete successfully (which made it
desirable to slightly re-structure that function, so that the error
cleanup can be done in one place).

Reported-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/drivers/xen/blkback/xenbus.c
+++ b/drivers/xen/blkback/xenbus.c
@@ -198,6 +198,7 @@ static int blkback_remove(struct xenbus_
be->blkif = NULL;
}

+ kfree(be->mode);
kfree(be);
dev->dev.driver_data = NULL;
write_unlock(&sysfs_read_lock);
@@ -278,6 +279,7 @@ static void backend_changed(struct xenbu
= container_of(watch, struct backend_info, backend_watch);
struct xenbus_device *dev = be->dev;
int cdrom = 0;
+ unsigned long handle;
char *device_type;

DPRINTK("");
@@ -295,12 +297,12 @@ static void backend_changed(struct xenbu
return;
}

- if ((be->major || be->minor) &&
- ((be->major != major) || (be->minor != minor))) {
- printk(KERN_WARNING
- "blkback: changing physical device (from %x:%x to "
- "%x:%x) not supported.\n", be->major, be->minor,
- major, minor);
+ if (be->major | be->minor) {
+ if (be->major != major || be->minor != minor)
+ printk(KERN_WARNING "blkback: "
+ "changing physical device (from %x:%x to "
+ "%x:%x) not supported.\n",
+ be->major, be->minor, major, minor);
return;
}

@@ -318,31 +320,30 @@ static void backend_changed(struct xenbu
kfree(device_type);
}

- if (be->major == 0 && be->minor == 0) {
- /* Front end dir is a number, which is used as the handle. */
+ /* Front end dir is a number, which is used as the handle. */
+ handle = simple_strtoul(strrchr(dev->otherend, '/') + 1, NULL, 0);

- char *p = strrchr(dev->otherend, '/') + 1;
- long handle = simple_strtoul(p, NULL, 0);
+ be->major = major;
+ be->minor = minor;

- be->major = major;
- be->minor = minor;
-
- err = vbd_create(be->blkif, handle, major, minor,
- (NULL == strchr(be->mode, 'w')), cdrom);
- if (err) {
- be->major = be->minor = 0;
- xenbus_dev_fatal(dev, err, "creating vbd structure");
- return;
- }
+ err = vbd_create(be->blkif, handle, major, minor,
+ (NULL == strchr(be->mode, 'w')), cdrom);

+ if (err)
+ xenbus_dev_fatal(dev, err, "creating vbd structure");
+ else {
err = xenvbd_sysfs_addif(dev);
if (err) {
vbd_free(&be->blkif->vbd);
- be->major = be->minor = 0;
xenbus_dev_fatal(dev, err, "creating sysfs entries");
- return;
}
+ }

+ if (err) {
+ kfree(be->mode);
+ be->mode = NULL;
+ be->major = be->minor = 0;
+ } else {
/* We're potentially connected now */
update_blkif_status(be->blkif);
}