Re: [stable] [PATCH] x86: Reserve FIRST_DEVICE_VECTOR inused_vectors bitmap

From: Greg KH
Date: Fri Oct 10 2008 - 16:21:22 EST


On Fri, Oct 10, 2008 at 04:01:54PM -0400, Stefan Bader wrote:
> Affected: 2.6.24-2.6.27
>
> Someone from the community found out, that after repeatedly unloading and
> loading a device driver that uses MSI IRQs, the system eventually assigned
> the vector initially reserved for IRQ0 to the device driver.
>
> The reason for this is, that although IRQ0 is tied to the FIRST_DEVICE_VECTOR
> when declaring the irq_vector table, the corresponding bit in the used_vectors
> map is not set. So, if vectors are released and assigned often enough, the
> vector will get assigned to another interrupt. This happens more often with
> MSI interrupts as those are exclusively using a vector.

Is there a problem with being assigned to IRQ0 in situations like this?

thanks,

greg k-h
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