Re: [stable] [PATCH] x86: Reserve FIRST_DEVICE_VECTOR in used_vectors bitmap

[Stefan Bader <stefan.bader@canonical.com>]

Greg KH wrote:
> On Fri, Oct 10, 2008 at 10:23:50PM +0200, Ingo Molnar wrote:
>> * Greg KH <greg@kroah.com> 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.
>>>>
>>>> Fix this by setting the bit for the FIRST_DEVICE_VECTOR in the bitmap.
>>>>
>>>> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
>>> Hint, if you want patches to go into the -stable tree, just add:
>>> 	cc: Stable <stable@kernel.org>
>>> to the patch when you submit it in the signed-off-by area, and it will
>>> be automatically sent to us when it goes into the main kernel tree.
>> yes. Note that this is a special case, as there will be no upstream 
>> commit to tag with Cc: <stable@kernel.org>, because this bug got 
>> eliminated via not backportable means: APIC code unification.
>>
>> Acked-by: Ingo Molnar <mingo@elte.hu>
> 
> So this is a -stable release only patch?  .28 will never get/need this?
> 
> thanks,
> 
> greg k-h

Correct. Tried to hint this by the Affected line but should have been more verbose.

Regards,
Stefan
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