diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-21 15:26:01 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-13 13:32:47 +0200 |
| commit | 9e66614b8c36b8d96bf7b271a3eacada1e4c589d (patch) | |
| tree | c868314808f12e9ef2017a4f4a518fcc9ed31234 /virt | |
| parent | e8c827bae71da914b094756f93d3b6d30ce85a89 (diff) | |
| download | lwn-9e66614b8c36b8d96bf7b271a3eacada1e4c589d.tar.gz lwn-9e66614b8c36b8d96bf7b271a3eacada1e4c589d.zip | |
KVM: async_pf: mm->mm_users can not pin apf->mm
commit 41c22f626254b9dc0376928cae009e73d1b6a49a upstream.
get_user_pages(mm) is simply wrong if mm->mm_users == 0 and exit_mmap/etc
was already called (or is in progress), mm->mm_count can only pin mm->pgd
and mm_struct itself.
Change kvm_setup_async_pf/async_pf_execute to inc/dec mm->mm_users.
kvm_create_vm/kvm_destroy_vm play with ->mm_count too but this case looks
fine at first glance, it seems that this ->mm is only used to verify that
current->mm == kvm->mm.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/async_pf.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index 8631d9c14320..f2c80d5451c3 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -85,7 +85,7 @@ static void async_pf_execute(struct work_struct *work) if (waitqueue_active(&vcpu->wq)) wake_up_interruptible(&vcpu->wq); - mmdrop(mm); + mmput(mm); kvm_put_kvm(vcpu->kvm); } @@ -98,7 +98,7 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) typeof(*work), queue); list_del(&work->queue); if (cancel_work_sync(&work->work)) { - mmdrop(work->mm); + mmput(work->mm); kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ kmem_cache_free(async_pf_cache, work); } @@ -162,7 +162,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, work->addr = gfn_to_hva(vcpu->kvm, gfn); work->arch = *arch; work->mm = current->mm; - atomic_inc(&work->mm->mm_count); + atomic_inc(&work->mm->mm_users); kvm_get_kvm(work->vcpu->kvm); /* this can't really happen otherwise gfn_to_pfn_async @@ -180,7 +180,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, return 1; retry_sync: kvm_put_kvm(work->vcpu->kvm); - mmdrop(work->mm); + mmput(work->mm); kmem_cache_free(async_pf_cache, work); return 0; } |