Re: [Xen-devel] [PATCH for 4.5] xen/arm: Initialize the domain vgic lock

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 18/12/2014 09:47, Ian Campbell wrote:
> On Wed, 2014-12-17 at 15:40 +0000, Julien Grall wrote:
> > The domain vgic lock is used uninitialized.
> >
> > Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>
> > ---
> >      This is a bug fix for Xen 4.5 and Xen 4.4. The vgic lock is used
> >      unitialized. Luckily we only use the field "raw" which is reset to 0
> >      during the domain allocation.
> >
> >      There is no harm to apply for Xen 4.5 because it will correctly set
> >      the spin_lock structure for a later usage.
> By your above reasoning there is also no point, is there? That said, I
> think we should take this since as you say it is harmless and good
> practice to initialise spinlocks even if not strictly necessary.
It's necessary to initialize spinlocks, not all the field of the 
spinlock is using the value 0 at initialization time.
What I meant if the current usage is fine. But if we want to debug 
spinlock, it won't work.
Regards,

--
Julien Grall

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