[PATCH 7.2 55/82] nvmet: pci-epf: put CQ ref on create_cq mapping failure

7.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yifei Gao <[email protected]>

commit 659ae9d02cb5d72c76f74fff7441eb8fb64d8f5c upstream.

nvmet_pci_epf_create_cq() calls nvmet_cq_create(), which takes a
reference on the controller and installs the completion queue. If the
subsequent PCI address-space mapping fails or returns a too-small partial
mapping, the function jumps to err_internal / err_unmap_queue without
calling nvmet_cq_put(). The matching put in nvmet_pci_epf_delete_cq() is
gated on NVMET_PCI_EPF_Q_LIVE, which is only set after the mapping
succeeds, so teardown never releases these references. A remote PCI host
that drives Create IO CQ commands with a failing PRP1/pci_addr therefore
leaks the CQ and a controller reference on each attempt.

Drop the CQ reference on the mapping-failure paths. The err_internal and
err_unmap_queue labels are only reachable after nvmet_cq_create() has
succeeded, so this pairs the create/put correctly.

Fixes: 0faa0fe6f90e ("nvmet: New NVMe PCI endpoint function target driver")
Cc: [email protected]
Reviewed-by: Damien Le Moal <[email protected]>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Yifei Gao <[email protected]>
Signed-off-by: Keith Busch <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/nvme/target/pci-epf.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/nvme/target/pci-epf.c
+++ b/drivers/nvme/target/pci-epf.c
@@ -1339,6 +1339,7 @@ err_unmap_queue:
 	nvmet_pci_epf_mem_unmap(ctrl->nvme_epf, &cq->pci_map);
 err_internal:
 	status = NVME_SC_INTERNAL | NVME_STATUS_DNR;
+	nvmet_cq_put(&cq->nvme_cq);
 err:
 	if (test_and_clear_bit(NVMET_PCI_EPF_Q_IRQ_ENABLED, &cq->flags))
 		nvmet_pci_epf_remove_irq_vector(ctrl, cq->vector);