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

From: Chris Wright
Date: Wed May 27 2009 - 16:30:53 EST


* Gregory Haskins (ghaskins@xxxxxxxxxx) 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@xxxxxxxxxx>
> ---
>
> 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
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