On 03/07/2023 19:56, Philippe Mathieu-Daudé wrote:
External email: Use caution opening links or attachments 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; } ?
Nice touch, it's indeed more accurate. Will change and post v2. Thanks!
