[Qemu-devel] [PATCH] pci: cleanly backout of pci_qdev_init()

[Alex Williamson <alex.williamson@redhat.com>]

If the init function of a device fails, as might happen with device
assignment, we never undo the work done by do_pci_register_device().
This not only causes a bit of a memory leak, but also leaves a bogus
pointer in the bus devices array that can cause a segfault or
garbage data from 'info pci'.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

 hw/pci.c |   17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index f167436..3d3560e 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -625,6 +625,14 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     return pci_dev;
 }
 
+static void do_pci_unregister_device(PCIDevice *pci_dev)
+{
+    qemu_free_irqs(pci_dev->irq);
+    pci_dev->bus->devices[pci_dev->devfn] = NULL;
+    pci_config_free(pci_dev);
+    return;
+}
+
 PCIDevice *pci_register_device(PCIBus *bus, const char *name,
                                int instance_size, int devfn,
                                PCIConfigReadFunc *config_read,
@@ -680,10 +688,7 @@ static int pci_unregister_device(DeviceState *dev)
         return ret;
 
     pci_unregister_io_regions(pci_dev);
-
-    qemu_free_irqs(pci_dev->irq);
-    pci_dev->bus->devices[pci_dev->devfn] = NULL;
-    pci_config_free(pci_dev);
+    do_pci_unregister_device(pci_dev);
     return 0;
 }
 
@@ -1652,8 +1657,10 @@ static int pci_qdev_init(DeviceState *qdev, DeviceInfo *base)
     if (pci_dev == NULL)
         return -1;
     rc = info->init(pci_dev);
-    if (rc != 0)
+    if (rc != 0) {
+        do_pci_unregister_device(pci_dev);
         return rc;
+    }
 
     /* rom loading */
     if (pci_dev->romfile == NULL && info->romfile != NULL)