From: Robin Murphy robin.murphy@arm.com
commit faf305c51aeabd1ea2d7131e798ef5f55f4a7750 upstream.
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@onstation.org Tested-by: Brian Masney masneyb@onstation.org Reported-by: Naresh Kamboju naresh.kamboju@linaro.org Fixes: 0ae349a0f33f ("iommu/qcom: Add qcom_iommu") Signed-off-by: Robin Murphy robin.murphy@arm.com Tested-by: Stephan Gerhold stephan@gerhold.net Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/iommu/qcom_iommu.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-)
--- a/drivers/iommu/qcom_iommu.c +++ b/drivers/iommu/qcom_iommu.c @@ -333,21 +333,19 @@ static void qcom_iommu_domain_free(struc { 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); } @@ -392,7 +390,7 @@ static void qcom_iommu_detach_dev(struct 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); @@ -405,8 +403,6 @@ static void qcom_iommu_detach_dev(struct 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,