Hi Jordan,
On 04/12/17 17:22, Jordan Crouse wrote:
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.
I missed this one before it got applied, but FWIW that behaviour was
actually somewhat intentional (see 05f80300dc8b). Callers really
shouldn't be trying to attach random unknown devices to IOMMU domains
anyway, but more crucially, now that iommu_{attach,detach}_group() work
everywhere I think the long-term plan is still to remove
iommu_{attach,detach}_device() completely.
I have no great objection to this patch myself, but do consider it a
heads-up that any callers it fixes are liable to be ridden roughshod
over by further API changes in future.
Robin.
Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
---
drivers/iommu/iommu.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3de5c0b..69fef99 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) {
--
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