> From: Bjorn Helgaas
> Subject: Re: [PATCH v2] PCI: endpoint: Fix NULL pointer dereference for -
> >get_features()
>
> On Fri, Dec 18, 2020 at 09:15:16PM +0530, Shradha Todi wrote:
> > get_features ops of pci_epc_ops may return NULL, causing NULL pointer
> > dereference in pci_epf_test_bind function. Let us add a check for
> > pci_epc_feature pointer in pci_epf_test_bind before we access it to
> > avoid any such NULL pointer dereference and return -ENOTSUPP in case
> > pci_epc_feature is not found.
>
> Can you add a Fixes: tag to identify where this broke to help people
decide
> where to backport the fix?
>
Thanks for the review. Sure we will add the Fixes tag and respin this patch.
> > Reviewed-by: Pankaj Dubey
> > Signed-off-by: Sriram Dash
> > Signed-off-by: Shradha Todi
> > ---
> > v2:
> > rebase on v1
> > v1:
> > https://protect2.fireeye.com/v1/url?k=6193fa90-3e08c3dd-619271df-0cc47
> > aa8f5ba-a79111ee2c1d1660&q=1&e=a9ee1ef7-2713-4099-8d06-
> 738532d78b26&u=
> > https%3A%2F%2Flore.kernel.org%2Fpatchwork%2Fpatch%2F1208269%2F
> >
> > drivers/pci/endpoint/functions/pci-epf-test.c | 13 -
> > 1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c
> > b/drivers/pci/endpoint/functions/pci-epf-test.c
> > index 66723d5..f1842e6 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -835,13 +835,16 @@ static int pci_epf_test_bind(struct pci_epf *epf)
> > return -EINVAL;
> >
> > epc_features = pci_epc_get_features(epc, epf->func_no);
> > - if (epc_features) {
> > - linkup_notifier = epc_features->linkup_notifier;
> > - core_init_notifier = epc_features->core_init_notifier;
> > - test_reg_bar = pci_epc_get_first_free_bar(epc_features);
> > - pci_epf_configure_bar(epf, epc_features);
> > + if (!epc_features) {
> > + dev_err(&epf->dev, "epc_features not implemented\n");
> > + return -EOPNOTSUPP;
> > }
> >
> > + linkup_notifier = epc_features->linkup_notifier;
> > + core_init_notifier = epc_features->core_init_notifier;
> > + test_reg_bar = pci_epc_get_first_free_bar(epc_features);
> > + pci_epf_configure_bar(epf, epc_features);
> > +
> > epf_test->test_reg_bar = test_reg_bar;
> > epf_test->epc_features = epc_features;
> >
> > --
> > 2.7.4
> >
