diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 2533ec84d1..efee62f40e 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -10578,7 +10578,6 @@ qemuNodeDeviceDetachFlags(virNodeDevicePtr dev,
     virPCIDevicePtr pci = NULL;
     unsigned domain, bus, slot, function;
     int ret = -1;
-    bool in_inactive_list = true;
     virNodeDeviceDefPtr def = NULL;
     char *xml = NULL;
 
@@ -10616,19 +10615,18 @@ qemuNodeDeviceDetachFlags(virNodeDevicePtr dev,
 
     virObjectLock(driver->activePciHostdevs);
     virObjectLock(driver->inactivePciHostdevs);
-    in_inactive_list = virPCIDeviceListFind(driver->inactivePciHostdevs, pci);
 
     if (virPCIDeviceDetach(pci, driver->activePciHostdevs,
-                           driver->inactivePciHostdevs, NULL) < 0)
+                           driver->inactivePciHostdevs, NULL) < 0) {
         goto out;
+    }
 
     ret = 0;
 out:
     virObjectUnlock(driver->inactivePciHostdevs);
     virObjectUnlock(driver->activePciHostdevs);
 cleanup:
-    if (in_inactive_list)
-        virPCIDeviceFree(pci);
+    virPCIDeviceFree(pci);
     virNodeDeviceDefFree(def);
     VIR_FREE(xml);
     return ret;
diff --git a/src/util/virpci.c b/src/util/virpci.c
index 1108ef2bd5..2f4032f516 100644
--- a/src/util/virpci.c
+++ b/src/util/virpci.c
@@ -1217,6 +1217,24 @@ cleanup:
     return result;
 }
 
+/* virPCIDeviceDetach:
+ *
+ * Detach this device from the host driver, attach it to the stub
+ * driver (previously set with virPCIDeviceSetStubDriver(), and add *a
+ * copy* of the object to the inactiveDevs list (if provided). This
+ * function will *never* consume dev, so the caller should free it.
+ *
+ * Returns 0 on success, -1 on failure (will fail if the device is
+ * already in the activeDevs list, but will be a NOP if the device is
+ * already bound to the stub).
+ *
+ * GENERAL NOTE: activeDevs should be a list of all PCI devices
+ * currently in use by a domain. inactiveDevs is a list of all PCI
+ * devices that libvirt has detached from the host driver + attached
+ * to the stub driver, but hasn't yet assigned to a domain. Any device
+ * that is still attached to its host driver should not be on either
+ * list.
+ */
 int
 virPCIDeviceDetach(virPCIDevicePtr dev,
                    virPCIDeviceList *activeDevs,
@@ -1241,9 +1259,13 @@ virPCIDeviceDetach(virPCIDevicePtr dev,
     if (virPCIDeviceBindToStub(dev, driver) < 0)
         return -1;
 
-    /* Add the dev into list inactiveDevs */
+    /* Add *a copy of* the dev into list inactiveDevs, if
+     * it's not already there.
+     */
     if (inactiveDevs && !virPCIDeviceListFind(inactiveDevs, dev)) {
-        if (virPCIDeviceListAdd(inactiveDevs, dev) < 0)
+        virPCIDevicePtr copy = virPCIDeviceCopy(dev);
+
+        if ((!copy) || virPCIDeviceListAdd(inactiveDevs, copy) < 0)
             return -1;
     }