4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Joerg Roedel <[email protected]> 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 <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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);
