iommu: Fix NULL group->domain dereference in pci_dev_reset_iommu_done()

Local sashiko review pointed it out that group->domain could be NULL when
a default domain fails to allocate during the first probe, which can crash
at domain->ops->attach_dev dereference in __iommu_attach_device() invoked
by pci_dev_reset_iommu_done().

pci_dev_reset_iommu_prepare() is fine as an old_domain pointer can be NULL.

Skip the re-attach in pci_dev_reset_iommu_done() to fix the bug.

Fixes: c279e83953d9 ("iommu: Introduce pci_dev_reset_iommu_prepare/done()")
Cc: stable@vger.kernel.org
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 61c12ba782066adcb597f1188b848ff734c9fc48..b8847cc43e764c5f8fade65a22de97873353edae 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -4073,8 +4073,13 @@ void pci_dev_reset_iommu_done(struct pci_dev *pdev)
        if (WARN_ON(!group->blocking_domain))
                return;
 
-       /* Re-attach RID domain back to group->domain */
-       if (group->domain != group->blocking_domain) {
+       /*
+        * Re-attach RID domain back to group->domain
+        *
+        * Leave the device parked in the blocking_domain if group->domain isn't
+        * initialized yet
+        */
+       if (group->domain && group->domain != group->blocking_domain) {
                WARN_ON(__iommu_attach_device(group->domain, &pdev->dev,
                                              group->blocking_domain));
        }