From 9ae9df035c274c89b7fe3dbc74cbe2fa63386668 Mon Sep 17 00:00:00 2001 From: Jordan Crouse Date: Wed, 20 Dec 2017 09:48:36 -0700 Subject: iommu: Check the result of iommu_group_get() for NULL The result of iommu_group_get() was being blindly used in both attach and detach which results in a dereference when trying to work with an unknown device. Signed-off-by: Jordan Crouse Signed-off-by: Alex Williamson --- drivers/iommu/iommu.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 3de5c0bcb5cc..69fef991c651 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -1303,6 +1303,9 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev) int ret; group = iommu_group_get(dev); + if (!group) + return -ENODEV; + /* * Lock the group to make sure the device-count doesn't * change while we are attaching @@ -1341,6 +1344,8 @@ void iommu_detach_device(struct iommu_domain *domain, struct device *dev) struct iommu_group *group; group = iommu_group_get(dev); + if (!group) + return; mutex_lock(&group->mutex); if (iommu_group_device_count(group) != 1) { -- cgit v1.2.3-59-g8ed1b