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

[Ingo Molnar <mingo@elte.hu>]

* 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>

	Ingo