On Mon, Nov 01, 2010 at 05:03:44PM +0800, Xiao Guangrong wrote: > In kvm_async_pf_wakeup_all(), we add a dummy apf to vcpu->async_pf.done > without holding vcpu->async_pf.lock, it will break if we are handling apfs > at this time. > This should never happen to well behaved guest, but malicious guest can do it on purpose.
> Also use 'list_empty_careful()' instead of 'list_empty()' > > Signed-off-by: Xiao Guangrong <[email protected]> Acked-by: Gleb Natapov <[email protected]> > --- > virt/kvm/async_pf.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c > index d57ec92..6ef3373 100644 > --- a/virt/kvm/async_pf.c > +++ b/virt/kvm/async_pf.c > @@ -200,7 +200,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) > { > struct kvm_async_pf *work; > > - if (!list_empty(&vcpu->async_pf.done)) > + if (!list_empty_careful(&vcpu->async_pf.done)) > return 0; > > work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); > @@ -211,7 +211,10 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) > get_page(bad_page); > INIT_LIST_HEAD(&work->queue); /* for list_del to work */ > > + spin_lock(&vcpu->async_pf.lock); > list_add_tail(&work->link, &vcpu->async_pf.done); > + spin_unlock(&vcpu->async_pf.lock); > + > vcpu->async_pf.queued++; > return 0; > } > -- > 1.7.0.4 -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
