Re: [Bluez-devel] Oops involving RFCOMM and sysfs

Cornelia Huck
2008-01-18T11:27:47Z

On Fri, 18 Jan 2008 18:34:55 +0800,
"Dave Young" <hidave.darkstar@gmail.com> wrote:

> On Jan 18, 2008 6:23 PM, Cornelia Huck <cornelia.huck@de.ibm.com> wrote:
> > On Fri, 18 Jan 2008 10:19:33 +0100,
> > Cornelia Huck <cornelia.huck@de.ibm.com> wrote:
> >
> > > >
> > > > 1314 if (IS_ERR(new_parent_kobj)) {
> > > > 1315 error = PTR_ERR(new_parent_kobj);
> > > > 1316 put_device(new_parent);
> > > > 1317 goto out;
> > > > 1318 }
> > > > 1319 pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
> > > > 1320 new_parent ? new_parent->bus_id : "<NULL>");
> > > > 1321 error = kobject_move(&dev->kobj, new_parent_kobj);
> > > > 1322 if (error) {
> > > > 1323 put_device(new_parent);
> > > >
> > > > imagine new_parent is NULL, then the new_parent_kobj should be put
> > >
> > > No, we would need a put_device_parent() (crappy name) which puts the
> > > reference iff get_device_parent() grabbed it.
> >
> > And looking at Greg's patchset, it has cleanup_device_parent(), which
> > does just that. But it is only called in device_del(), not when
> > device_move() has errors.
> >
> > (get_device_parent() also always returns a pointer to a kobject or
> > NULL, so we can get rid of those IS_ERR() checks in setup_parent() and
> > device_move() as well.)
> >
>
> Hmm, thanks.
> I will be offline during weekend, but I will still check the
> device_move and other code if I have time.

Just hacked together the following against Greg's tree:

COMPLETELY UNTESTED DO NOT APPLY

---
drivers/base/core.c | 33 ++++++++++++++++-----------------
1 files changed, 16 insertions(+), 17 deletions(-)

--- linux-2.6.orig/drivers/base/core.c
+++ linux-2.6/drivers/base/core.c
@@ -553,6 +553,8 @@ static struct kobject *get_device_parent
}

static inline void cleanup_device_parent(struct device *dev) {}
+static inline void cleanup_glue_dir(struct device *dev,
+ struct kobject *kobj) {}
#else
static struct kobject *virtual_device_parent(struct device *dev)
{
@@ -617,27 +619,27 @@ static struct kobject *get_device_parent
return NULL;
}

-static void cleanup_device_parent(struct device *dev)
+static void cleanup_glue_dir(struct device *dev, struct kobject *kobj)
{
- struct kobject *glue_dir = dev->kobj.parent;
-
/* see if we live in a "glue" directory */
- if (!dev->class || glue_dir->kset != &dev->class->class_dirs)
+ if (!dev->class || kobj->kset != &dev->class->class_dirs)
return;

- kobject_put(glue_dir);
+ kobject_put(kobj);
+}
+
+static void cleanup_device_parent(struct device *dev)
+{
+ cleanup_glue_dir(dev, dev->kobj.parent);
}
#endif

-static int setup_parent(struct device *dev, struct device *parent)
+static void setup_parent(struct device *dev, struct device *parent)
{
struct kobject *kobj;
kobj = get_device_parent(dev, parent);
- if (IS_ERR(kobj))
- return PTR_ERR(kobj);
if (kobj)
dev->kobj.parent = kobj;
- return 0;
}

static int device_add_class_symlinks(struct device *dev)
@@ -782,9 +784,7 @@ int device_add(struct device *dev)
pr_debug("device: '%s': %s\n", dev->bus_id, __FUNCTION__);

parent = get_device(dev->parent);
- error = setup_parent(dev, parent);
- if (error)
- goto Error;
+ setup_parent(dev, parent);

/* first, register with generic layer. */
error = kobject_add(&dev->kobj, dev->kobj.parent, "%s", dev->bus_id);
@@ -862,6 +862,7 @@ int device_add(struct device *dev)
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
kobject_del(&dev->kobj);
Error:
+ cleanup_device_parent(dev);
if (parent)
put_device(parent);
goto Done;
@@ -1303,15 +1304,12 @@ int device_move(struct device *dev, stru

new_parent = get_device(new_parent);
new_parent_kobj = get_device_parent (dev, new_parent);
- if (IS_ERR(new_parent_kobj)) {
- error = PTR_ERR(new_parent_kobj);
- put_device(new_parent);
- goto out;
- }
+
pr_debug("device: '%s': %s: moving to '%s'\n", dev->bus_id,
__FUNCTION__, new_parent ? new_parent->bus_id : "<NULL>");
error = kobject_move(&dev->kobj, new_parent_kobj);
if (error) {
+ cleanup_glue_dir(dev, new_parent_kobj);
put_device(new_parent);
goto out;
}
@@ -1334,6 +1332,7 @@ int device_move(struct device *dev, stru
klist_add_tail(&dev->knode_parent,
&old_parent->klist_children);
}
+ cleanup_glue_dir(dev, new_parent_kobj);
put_device(new_parent);
goto out;
}