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authorSheng Yang <sheng@linux.intel.com>2009-12-15 10:28:07 +0800
committerMarcelo Tosatti <mtosatti@redhat.com>2009-12-27 13:36:31 -0200
commitfae3a3536a6fecedebd49fa847f810e599bfb132 (patch)
tree18b555c3f6bcc6735fd7a90db2c398a35e29c84e /virt/kvm/assigned-dev.c
parentfb341f572d26e0786167cd96b90cc4febed830cf (diff)
KVM: Fix possible circular locking in kvm_vm_ioctl_assign_device()
One possible order is: KVM_CREATE_IRQCHIP ioctl(took kvm->lock) -> kvm_iobus_register_dev() -> down_write(kvm->slots_lock). The other one is in kvm_vm_ioctl_assign_device(), which take kvm->slots_lock first, then kvm->lock. Update the comment of lock order as well. Observe it due to kernel locking debug warnings. Cc: stable@kernel.org Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt/kvm/assigned-dev.c')
-rw-r--r--virt/kvm/assigned-dev.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index fd9c097b760..f73de631e3e 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -508,8 +508,8 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
struct kvm_assigned_dev_kernel *match;
struct pci_dev *dev;
- down_read(&kvm->slots_lock);
mutex_lock(&kvm->lock);
+ down_read(&kvm->slots_lock);
match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
assigned_dev->assigned_dev_id);
@@ -573,8 +573,8 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
}
out:
- mutex_unlock(&kvm->lock);
up_read(&kvm->slots_lock);
+ mutex_unlock(&kvm->lock);
return r;
out_list_del:
list_del(&match->list);
@@ -585,8 +585,8 @@ out_put:
pci_dev_put(dev);
out_free:
kfree(match);
- mutex_unlock(&kvm->lock);
up_read(&kvm->slots_lock);
+ mutex_unlock(&kvm->lock);
return r;
}