diff mbox series

[V3,1/2] iommu: Fix race condition during default domain allocation

Message ID 1628570641-9127-2-git-send-email-amhetre@nvidia.com (mailing list archive)
State New, archived
Headers show
Series iommu/arm-smmu: Fix races in iommu domain/group creation | expand

Commit Message

Ashish Mhetre Aug. 10, 2021, 4:44 a.m. UTC 
When two devices with same SID are getting probed concurrently through
iommu_probe_device(), the iommu_domain sometimes is getting allocated more
than once as call to iommu_alloc_default_domain() is not protected for
concurrency. Furthermore, it leads to each device holding a different
iommu_domain pointer, separate IOVA space and only one of the devices'
domain is used for translations from IOMMU. This causes accesses from other
device to fault or see incorrect translations.
Fix this by protecting iommu_alloc_default_domain() call with group->mutex
and let all devices with same SID share same iommu_domain.

Signed-off-by: Ashish Mhetre <amhetre@nvidia.com>
---
 drivers/iommu/iommu.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 5419c4b..80c5a1c 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -273,7 +273,9 @@  int iommu_probe_device(struct device *dev)
 	 * support default domains, so the return value is not yet
 	 * checked.
 	 */
+	mutex_lock(&group->mutex);
 	iommu_alloc_default_domain(group, dev);
+	mutex_unlock(&group->mutex);
 
 	if (group->default_domain) {
 		ret = __iommu_attach_device(group->default_domain, dev);