vfio/spapr_tce: Fix incorrect tce_iommu_group memory free

The @tcegrp variable is used in 1) a loop over attached groups
2) it stores a pointer to a newly allocated tce_iommu_group if 1) found
nothing. However the error handler does not distinguish how we got there
and incorrectly releases memory for a found+incompatible group.

This fixes it by adding another error handling case.

Fixes: 0bd971676e68 ("powerpc/powernv/npu: Add compound IOMMU groups")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 8ce9ad2..babef8b 100644 (file)
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -1234,7 +1234,7 @@ release_exit:
 static int tce_iommu_attach_group(void *iommu_data,
                struct iommu_group *iommu_group)
 {
-       int ret;
+       int ret = 0;
        struct tce_container *container = iommu_data;
        struct iommu_table_group *table_group;
        struct tce_iommu_group *tcegrp = NULL;
@@ -1287,13 +1287,13 @@ static int tce_iommu_attach_group(void *iommu_data,
                        !table_group->ops->release_ownership) {
                if (container->v2) {
                        ret = -EPERM;
-                       goto unlock_exit;
+                       goto free_exit;
                }
                ret = tce_iommu_take_ownership(container, table_group);
        } else {
                if (!container->v2) {
                        ret = -EPERM;
-                       goto unlock_exit;
+                       goto free_exit;
                }
                ret = tce_iommu_take_ownership_ddw(container, table_group);
                if (!tce_groups_attached(container) && !container->tables[0])
@@ -1305,10 +1305,11 @@ static int tce_iommu_attach_group(void *iommu_data,
                list_add(&tcegrp->next, &container->group_list);
        }
 
-unlock_exit:
+free_exit:
        if (ret && tcegrp)
                kfree(tcegrp);
 
+unlock_exit:
        mutex_unlock(&container->lock);
 
        return ret;