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SubjectRe: [PATCH] KVM: remove printing of vcpu address
On Mon, Oct 09, 2017 at 05:31:41PM +1100, Tobin C. Harding wrote:
> Code currently prints the address of the kvm_vcpu structure in an error
> message. It is not immediately clear what value this address adds to
> the error string, we can use the vcpu ID instead.

I would say it's not immediately clear how the vcpu ID is more valuable.
The pointer identifies a unique vcpu across all VMs, vcpu ID does not.

> Printing unnecessary
> kernel addresses to dmesg poses a security risk.

Is this really a concern we have for error messages? I understand you
can get a single pointer revealed if you have broken hardware or if we
have a bug, but I see numerious other examples in the kernel.

If anything, we can remote printing the vcpu pointer entirely.


Thanks,
-Christoffer
>
> Remove the address from error message output, show vcpu ID instead.
>
> Signed-off-by: Tobin C. Harding <me@tobin.cc>
> ---
> virt/kvm/arm/arch_timer.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index 8e89d63005c7..ca6c331cad28 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -88,7 +88,7 @@ static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
> * interrupt at this point is a sure sign of some major
> * breakage.
> */
> - pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
> + pr_warn("Unexpected interrupt %d on vcpu ID %d\n", irq, vcpu->vcpu_id);
> return IRQ_HANDLED;
> }
>
> --
> 2.7.4
>

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