On 3/7/23 18:39, Avihai Horon wrote:
vfio_realize() has the following flow:
1. vfio_bars_prepare() -- sets VFIOBAR->size.
2. msix_early_setup().
3. vfio_bars_register() -- allocates VFIOBAR->mr.
After vfio_bars_prepare() is called msix_early_setup() can fail. If it
does fail, vfio_bars_register() is never called and VFIOBAR->mr is not
allocated.
In this case, vfio_bars_finalize() is called as part of the error flow
to free the bars' resources. However, vfio_bars_finalize() calls
object_unparent() for VFIOBAR->mr unconditionally and thus we get a null
pointer dereference.
Fix it by checking VFIOBAR->mr in vfio_bars_finalize().
Fixes: 89d5202edc50 ("vfio/pci: Allow relocating MSI-X MMIO")
Signed-off-by: Avihai Horon <avih...@nvidia.com>
---
hw/vfio/pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index ab6645ba60..95e077082b 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1752,7 +1752,7 @@ static void vfio_bars_finalize(VFIOPCIDevice *vdev)
vfio_bar_quirk_finalize(vdev, i);
vfio_region_finalize(&bar->region);
- if (bar->size) {
+ if (bar->size && bar->mr) {
object_unparent(OBJECT(bar->mr));
g_free(bar->mr);
}
What about:
if (bar->mr) {
assert(bar->size);
object_unparent(OBJECT(bar->mr));
g_free(bar->mr);
bar->mr = NULL;
}
?
