iommu/vt-d: Fix dead-locks in disable_dmar_iommu() path

It turns out that the disable_dmar_iommu() code-path tried
to get the device_domain_lock recursivly, which will
dead-lock when this code runs on dmar removal. Fix both
code-paths that could lead to the dead-lock.

Fixes: 55d940430ab9 ('iommu/vt-d: Get rid of domain->iommu_lock')
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a4407eabf0e64fbacba5573bc3eb91204c97a19c..3965e73db51cef0f3d3b5593da18c9d9fe25fd9e 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1711,6 +1711,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)
        if (!iommu->domains || !iommu->domain_ids)
                return;
 
+again:
        spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_entry_safe(info, tmp, &device_domain_list, global) {
                struct dmar_domain *domain;
@@ -1723,10 +1724,19 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)
 
                domain = info->domain;
 
-               dmar_remove_one_dev_info(domain, info->dev);
+               __dmar_remove_one_dev_info(info);
 
-               if (!domain_type_is_vm_or_si(domain))
+               if (!domain_type_is_vm_or_si(domain)) {
+                       /*
+                        * The domain_exit() function  can't be called under
+                        * device_domain_lock, as it takes this lock itself.
+                        * So release the lock here and re-run the loop
+                        * afterwards.
+                        */
+                       spin_unlock_irqrestore(&device_domain_lock, flags);
                        domain_exit(domain);
+                       goto again;
+               }
        }
        spin_unlock_irqrestore(&device_domain_lock, flags);