4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Joerg Roedel <jroedel@xxxxxxx>
commit bea64033dd7b5fb6296eda8266acab6364ce1554 upstream.
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@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iommu/intel-iommu.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1672,6 +1672,7 @@ static void disable_dmar_iommu(struct in
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;
@@ -1684,10 +1685,19 @@ static void disable_dmar_iommu(struct in
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);
--
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