Messages in this thread | | | From | Dmitry Torokhov <> | Subject | Re: [PATCH] fujitsu-laptop: driver [un]registration fixes | Date | Mon, 21 Dec 2009 14:46:32 -0800 |
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Hi Jonathan,
On Monday 21 December 2009 02:32:40 pm Jonathan Woithe wrote: > Hi Dmitry > > > On Wed, Jul 29, 2009 at 10:15:33PM +0200, Bartlomiej Zolnierkiewicz wrote: > > > @@ -722,22 +722,22 @@ static int acpi_fujitsu_add(struct acpi_ > > > > > > return result; > > > > > > -end: > > > +err_unregister_input_dev: > > > + input_unregister_device(input); > > > err_free_input_dev: > > > input_free_device(input); > > > err_stop: > > > > Just noticed it scanning ACPI list. You must not use input_free_device() > > after calling input_unregister_device() since unregister likely drops the > > last reference to the device and it will get freed by input core. > > So what's the correct way to deal with that in this case? Something like > > -end: > +err_unregister_input_dev: > + input_unregister_device(input); > + goto err_stop; > err_free_input_dev: > input_free_device(input); > err_stop: > > (with a short comment to explain the goto) would circumvent the problem but > it looks ugly (at least to my eyes - I've never really liked "goto"s :-) ).
Just do "input = NULL;" after calling input_unregister_device() - input_free_device() is like kfree() and will happily ignore passed NULL pointers.
Or rearrange the code to register device last, when everything is ready.
> > > For polled input devices you need to use both unregister and free though > > because polled device structure is not refcounted (but underlying input > > device is). > > This isn't a polled input device AFAIK so this doesn't apply here, right?
Right, it was more of a general statement so I don't get bunch of patches removing input_free_polled_device() after calls to input_unregister_polled_device() ;)
-- Dmitry
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