On Mon, 25 Sep 2023 07:21:32 +0100,
Dinghao Liu <dinghao.liu@xxxxxxxxxx> wrote:
>
> xgene_allocate_domains() will call irq_domain_remove() to free
> msi->inner_domain on failure. However, its caller, xgene_msi_probe(),
> will also call irq_domain_remove() through xgene_msi_remove() on the
> same failure, which may lead to a use-after-free. Set the freed pointer
> to NULL to fix this issue.
>
> Fixes: dcd19de36775 ("PCI: xgene: Add APM X-Gene v1 PCIe MSI/MSIX termination driver")
> Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
> ---
> drivers/pci/controller/pci-xgene-msi.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
> index 3ce38dfd0d29..c0192c5ff0f3 100644
> --- a/drivers/pci/controller/pci-xgene-msi.c
> +++ b/drivers/pci/controller/pci-xgene-msi.c
> @@ -253,6 +253,7 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
>
> if (!msi->msi_domain) {
> irq_domain_remove(msi->inner_domain);
> + msi->inner_domain = NULL;
> return -ENOMEM;
> }
Why can't we just drop the irq_domain_remove() call here instead, and
simply rely on xgene_msi_remove() to do the right thing? Something
like the untested patch below.
Thanks,
M.
diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
index 0234e528b9a5..f98c9eb7bebf 100644
--- a/drivers/pci/controller/pci-xgene-msi.c
+++ b/drivers/pci/controller/pci-xgene-msi.c
@@ -251,10 +251,8 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
&xgene_msi_domain_info,
msi->inner_domain);
- if (!msi->msi_domain) {
- irq_domain_remove(msi->inner_domain);
+ if (!msi->msi_domain)
return -ENOMEM;
- }
return 0;
}
--
Without deviation from the norm, progress is not possible.
