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Subject[PATCH 2/4] iommu/vt-d: Fix PCI device refcount leak in prq_event_thread()
Date
From: Yang Yingliang <yangyingliang@huawei.com>

As comment of pci_get_domain_bus_and_slot() says, it returns a pci device
with refcount increment, when finish using it, the caller must decrease
the reference count by calling pci_dev_put(). So call pci_dev_put() after
using the 'pdev' to avoid refcount leak.

Besides, if the 'pdev' is null or intel_svm_prq_report() returns error,
there is no need to trace this fault.

Fixes: 06f4b8d09dba ("iommu/vt-d: Remove unnecessary SVA data accesses in page fault path")
Suggested-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221119144028.2452731-1-yangyingliang@huawei.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/svm.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index fe615c53479c..03b25358946c 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -748,12 +748,16 @@ static irqreturn_t prq_event_thread(int irq, void *d)
* If prq is to be handled outside iommu driver via receiver of
* the fault notifiers, we skip the page response here.
*/
- if (!pdev || intel_svm_prq_report(iommu, &pdev->dev, req))
- handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
+ if (!pdev)
+ goto bad_req;

- trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
- req->priv_data[0], req->priv_data[1],
- iommu->prq_seq_number++);
+ if (intel_svm_prq_report(iommu, &pdev->dev, req))
+ handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
+ else
+ trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
+ req->priv_data[0], req->priv_data[1],
+ iommu->prq_seq_number++);
+ pci_dev_put(pdev);
prq_advance:
head = (head + sizeof(*req)) & PRQ_RING_MASK;
}
--
2.34.1
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