4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Joerg Roedel <jroedel@xxxxxxx>
commit eebb8034a5be8c2177cbf07ca2ecd2ff8a058958 upstream.
IOMMU drivers that do not support default domains, but make
use of the the group->domain pointer can get that pointer
overwritten with NULL on device add/remove.
Make sure this can't happen by only overwriting the domain
pointer when it is NULL.
Fixes: 1228236de5f9 ('iommu: Move default domain allocation to iommu_group_get_for_dev()')
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iommu/iommu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -848,7 +848,8 @@ struct iommu_group *iommu_group_get_for_
if (!group->default_domain) {
group->default_domain = __iommu_domain_alloc(dev->bus,
IOMMU_DOMAIN_DMA);
- group->domain = group->default_domain;
+ if (!group->domain)
+ group->domain = group->default_domain;
}
ret = iommu_group_add_device(group, dev);
--
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