Messages in this thread | | | Date | Wed, 6 Feb 2019 17:46:57 +0100 | From | Greg KH <> | Subject | Re: [RFC v1 0/3] Address potential user-after-free on module unload |
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On Tue, Feb 05, 2019 at 02:12:31PM -0500, Sven Van Asbroeck wrote: > On Tue, Feb 5, 2019 at 1:43 PM Greg KH <gregkh@linuxfoundation.org> wrote: > > > > > > It really should happen when the device is removed (if it is a driver > > that binds to a device.) > > Absolutely. That's why I'm advocating adding a devm_init_work(), > which will take care of this automatically. > > But it's of course not universally applicable. Not all drivers use devm.
Ick, no, watch out for devm() calls. Odds are this is _NOT_ what you want to do for a device. Remember when devm calls get freed (hint, not at driver unbind/unload, but at device structure removal.
By creating a work queue, you are suddenly tying module code to a device memory structure lifespan, both of which are totally independant.
It's the same issue with the devm irq call, that has been nothing but a nightmare as everyone gets it wrong. Try to learn from our past mistakes please :)
thanks,
greg k-h
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