Re: [PATCH] kvm: fix coalesced_mmio leak on shutdown

[Chris Wright <chrisw@sous-sol.org>]

* Gregory Haskins (ghaskins@novell.com) wrote:
> It would appear that we are invoking kfree() on the wrong pointer in the
> destructor for the coalesced_mmio device.  This would result in a potential
> leak during shutdown.

Happens to work and not leak:

struct kvm_coalesced_mmio_dev { 
        struct kvm_io_device dev;
        struct kvm *kvm;
        int nb_zones;
        struct kvm_coalesced_mmio_zone zone[KVM_COALESCED_MMIO_ZONE_MAX];
};

> Signed-off-by: Gregory Haskins <ghaskins@novell.com>
> ---
> 
>  virt/kvm/coalesced_mmio.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
> index 5ae620d..03ea280 100644
> --- a/virt/kvm/coalesced_mmio.c
> +++ b/virt/kvm/coalesced_mmio.c
> @@ -80,7 +80,10 @@ static void coalesced_mmio_write(struct kvm_io_device *this,
>  
>  static void coalesced_mmio_destructor(struct kvm_io_device *this)
>  {
> -	kfree(this);
> +	struct kvm_coalesced_mmio_dev *dev =
> +		(struct kvm_coalesced_mmio_dev *)this->private;

I think container_of() makes more sense here.

thanks,
-chris