Messages in this thread | | | From | Michael Buesch <> | Subject | Re: Threaded interrupt handlers broken? | Date | Fri, 4 Sep 2009 21:05:51 +0200 |
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On Friday 04 September 2009 20:55:52 Michael Buesch wrote: > On Monday 17 August 2009 14:30:31 Michael Buesch wrote: > > Also works. Thanks. > > > > Tested-by: Michael Buesch <mb@bu3sch.de> > > Hm, I've got a strange problem here related to threaded IRQs and rmmod. > > If I do this sequence, it crashes the machine: > request_threaded_irq(); > free_irq(); > rmmod module > modprobe module > request_threaded_irq(); > *boom* > > Here are some oops messages. These are almost always different, so I > guess it crashes in IRQ context at random places when the IRQ triggers. > http://bu3sch.de/misc/irq_crash1.JPG > http://bu3sch.de/misc/irq_crash2.JPG > > It seems to be a NULL pointer dereference somewhere, but I can't locate it. > Note that it does not happen, if I omit the rmmod. >
Ok, what I see now is that the IRQ thread that belongs to the driver is not destroyed on free_irq(). So it is dangling and after rmmod/modprobe it will crash on interrupt, because the module is relocated. Bringing the device up and down several times (without reloading the module), which does several request_threaded_irq(); free_irq() sequences in a row, creates a new IRQ thread each time but does not destroy the old one.
-- Greetings, Michael.
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