On Tue, 18 Mar 2008 14:54:17 -0400, Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote: I'm sorry, but I'm weak. I'll have to poke Greg (to cc:), although I know he's pretty busy, but I don't grok sysfs and kobjects. So: > > > > If a device was grabbed through evdev and then became disconnected, > > > > we oops on close. This happens because input_release_device uses memory > > > > which was freed. > > > > > Could you tell me what memory is freed? > > > > The input_dev is freed. [...] > > > [] As far as I understand the > > > the input_dev structure shold be pinned in memory by the driver > > > core since we have this link: > > > > > > evdev->dev.parent = &input_dev->dev; > > > > > > This should guarantee that input_device is not gone until we > > > call evdev_free which should be done way after the ungrab. > > > > I don't think anyone checks this, unless the accompaining refcount > > is set. > I dont oppose your patch, I am just trying to understand why it > is needed because driver core should pin the parent device as > far as I understand and if this does not happen there are other > issues in input core that need to be taken care of. > > From what I see we should be automatically taking the reference > to parent kobject in > > kobject_add_internal(): > parent = kobject_get(kobj->parent); > > perent is set in kobject_add_varg(): > kobj->parent = parent; > > .. which is called from kobject_add() which is called from > device_add(). Hmm, I see it now. OK. > Hmm, I wonder if obsolete sysfs links mess up proper parenting > data... I dont think I have obsolete links set up on any of my > boxes, can you see if oops goes away if you disable deprectated > sysfs? If so then instead of checking exist flag we need explicitely > take reference to the parent input_dev. [] I'll check this. -- Pete -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
