Messages in this thread Patch in this message | | | Date | Mon, 01 Nov 2010 17:03:44 +0800 | From | Xiao Guangrong <> | Subject | [RFC PATCH v2 6/7] KVM: fix the race while wakeup all pv guest |
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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.
Also use 'list_empty_careful()' instead of 'list_empty()'
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> --- 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
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