Currently, the implementation of qcom_iommu_domain_free() is guaranteed
to do one of two things: WARN() and leak everything, or dereference NULL
and crash. That alone is terrible, but in fact the whole idea of trying
to track the liveness of a domain via the qcom_domain->iommu pointer as
a sanity check is full of fundamentally flawed assumptions. Make things
robust and actually functional by not trying to be quite so clever.
Reported-by: Brian Masney <masneyb@xxxxxxxxxxxxx>
Tested-by: Brian Masney <masneyb@xxxxxxxxxxxxx>
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Fixes: 0ae349a0f33f ("iommu/qcom: Add qcom_iommu")
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
---
drivers/iommu/qcom_iommu.c | 28 ++++++++++++----------------
1 file changed, 12 insertions(+), 16 deletions(-)
diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
index 39759db4f003..4328da0b0a9f 100644
--- a/drivers/iommu/qcom_iommu.c
+++ b/drivers/iommu/qcom_iommu.c
@@ -344,21 +344,19 @@ static void qcom_iommu_domain_free(struct iommu_domain *domain)
{
struct qcom_iommu_domain *qcom_domain = to_qcom_iommu_domain(domain);
- if (WARN_ON(qcom_domain->iommu)) /* forgot to detach? */
- return;
-
iommu_put_dma_cookie(domain);
- /* NOTE: unmap can be called after client device is powered off,
- * for example, with GPUs or anything involving dma-buf. So we
- * cannot rely on the device_link. Make sure the IOMMU is on to
- * avoid unclocked accesses in the TLB inv path:
- */
- pm_runtime_get_sync(qcom_domain->iommu->dev);
-
- free_io_pgtable_ops(qcom_domain->pgtbl_ops);
-
- pm_runtime_put_sync(qcom_domain->iommu->dev);
+ if (qcom_domain->iommu) {
+ /*
+ * NOTE: unmap can be called after client device is powered
+ * off, for example, with GPUs or anything involving dma-buf.
+ * So we cannot rely on the device_link. Make sure the IOMMU
+ * is on to avoid unclocked accesses in the TLB inv path:
+ */
+ pm_runtime_get_sync(qcom_domain->iommu->dev);
+ free_io_pgtable_ops(qcom_domain->pgtbl_ops);
+ pm_runtime_put_sync(qcom_domain->iommu->dev);
+ }
kfree(qcom_domain);
}
@@ -404,7 +402,7 @@ static void qcom_iommu_detach_dev(struct iommu_domain *domain, struct device *de
struct qcom_iommu_domain *qcom_domain = to_qcom_iommu_domain(domain);
unsigned i;
- if (!qcom_domain->iommu)
+ if (WARN_ON(!qcom_domain->iommu))
return;
pm_runtime_get_sync(qcom_iommu->dev);
@@ -417,8 +415,6 @@ static void qcom_iommu_detach_dev(struct iommu_domain *domain, struct device *de
ctx->domain = NULL;
}
pm_runtime_put_sync(qcom_iommu->dev);
-
- qcom_domain->iommu = NULL;
}
static int qcom_iommu_map(struct iommu_domain *domain, unsigned long iova,
--
2.23.0.dirty
