Messages in this thread | | | Date | Fri, 10 Oct 2008 16:24:24 -0400 | From | Stefan Bader <> | Subject | Re: [stable] [PATCH] x86: Reserve FIRST_DEVICE_VECTOR in used_vectors bitmap |
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Greg KH wrote: > 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 Yes, since IRQ0 is still wanted and used by the system timer. After the module get unloaded again, the vector gets freed and no timer interrupt is delivered anymore.
Stefan
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