Messages in this thread | | | Date | Wed, 24 Aug 2011 18:33:54 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] arch/x86/kernel/microcode_core.c: add missing platform_device_unregister |
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On Wed, Aug 24, 2011 at 05:44:08PM +0200, Julia Lawall wrote: > That seems like a fairly big change. Is it desirable to move the calls to > sysdev_driver_register and microcode_dev_init up over the get_online_cpus > ... put_online_cpus sequence?
Well, you need microcode_pdev for request_firmware() which happens when you do sysdev_driver_register() so it has to run after platform_device_register_simple().
And the microcode_dev_init() thing got moved further down in 871b72dd1e12afc3f024479531d25a9339d2e3f9 but its counterpart microcode_dev_exit() is mistakenly called if platform_device_register_simple() fails which is clearly another bug.
And frankly, microcode_dev_init() is strictly needed only for the CONFIG_MICROCODE_OLD_INTERFACE. And on the driver destroy path microcode_exit() is calling microcode_dev_exit() first so it could be that 871b72dd1e12afc3f024479531d25a9339d2e3f9 mistakenly moved the microcode_dev_init() call down.
I guess you could move the microcode_dev_init() call up, before platform_device_register_simple() but this needs testing on Intel because they still can do microcode loading over the old interface using microcode_ctl userspace helper...
Or, you can do a bit cleaner version of the goto-with-labels thing by adding a helper like this:
static void __microcode_sysdev_unregister(void) { get_online_cpus(); mutex_lock(µcode_mutex);
sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver);
mutex_unlock(µcode_mutex); put_online_cpus(); }
and call it both on the error-out path in microcode_init(), and in microcode_exit().
Oh boy, the rabbit hole turns out to be pretty deep once you go down into it :-).
Btw, I totally understand if you've lost all desire to fix that properly after all this :-).
Thanks.
-- Regards/Gruss, Boris.
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