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| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2010-11-01 17:03:44 +0800 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-01-12 11:29:03 +0200 |
| commit | 64f638c7c44fa87e65f51eaf0f8302b9cba2d696 (patch) | |
| tree | 8aff59c0397f9231f5889d21b682a7a76e7dc66d | |
| parent | 15096ffceabb9693306982127348890886384aaa (diff) | |
| download | lwn-64f638c7c44fa87e65f51eaf0f8302b9cba2d696.tar.gz lwn-64f638c7c44fa87e65f51eaf0f8302b9cba2d696.zip | |
KVM: fix the race while wakeup all pv guest
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>
Acked-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| -rw-r--r-- | 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 100c66ee0220..74268b4c2ee1 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -196,7 +196,7 @@ 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); @@ -207,7 +207,10 @@ 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; } |