On Mon, Jan 31, 2022 at 12:06:21PM +0100, Christian Gmeiner wrote:
> Am Do., 27. Jan. 2022 um 23:29 Uhr schrieb Bjorn Helgaas <helgaas@xxxxxxxxxx>:
> >
> > On Mon, Jan 24, 2022 at 01:21:22PM +0100, Christian Gmeiner wrote:
> > > This reverts commit 19e863828acf6d8ac8475ba1fd93c0fe17fdc4ef.
> > >
> > > Fixes the following oops:
> > > Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
> >
> > Hi Christian,
> >
> > Would you mind trying this patch?
> >
>
> Works - thanks. You can add my Tested-by.
Thanks, applied to for-linus for v5.17.
>
> > commit 9d36a93af8fe ("PCI: j721e: Initialize pcie->cdns_pcie before using it")
> > Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Date: Thu Jan 27 15:49:49 2022 -0600
> >
> > PCI: j721e: Initialize pcie->cdns_pcie before using it
> >
> > Christian reported a NULL pointer dereference in j721e_pcie_probe() caused
> > by 19e863828acf ("PCI: j721e: Drop redundant struct device *"), which
> > removed struct j721e_pcie.dev since there's another copy in struct
> > cdns_pcie.dev reachable via j721e_pcie->cdns_pcie->dev.
> >
> > The problem is that j721e_pcie->cdns_pcie was dereferenced before being
> > initialized:
> >
> > j721e_pcie_probe
> > pcie = devm_kzalloc() # struct j721e_pcie
> > j721e_pcie_ctrl_init(pcie)
> > dev = pcie->cdns_pcie->dev <-- dereference cdns_pcie
> > switch (mode) {
> > case PCI_MODE_RC:
> > cdns_pcie = ... # alloc as part of pci_host_bridge
> > pcie->cdns_pcie = cdns_pcie <-- initialize pcie->cdns_pcie
> >
> > Initialize pcie->cdns_pcie before it is used.
> >
> > Fixes: 19e863828acf ("PCI: j721e: Drop redundant struct device *")
> > Reported-by: Christian Gmeiner <christian.gmeiner@xxxxxxxxx>
> > Link: https://lore.kernel.org/r/20220124122132.435743-1-christian.gmeiner@xxxxxxxxx
> > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> >
> > diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
> > index 489586a4cdc7..5d950c1d9fd0 100644
> > --- a/drivers/pci/controller/cadence/pci-j721e.c
> > +++ b/drivers/pci/controller/cadence/pci-j721e.c
> > @@ -372,10 +372,48 @@ static int j721e_pcie_probe(struct platform_device *pdev)
> >
> > mode = (u32)data->mode;
> >
> > + switch (mode) {
> > + case PCI_MODE_RC:
> > + if (!IS_ENABLED(CONFIG_PCIE_CADENCE_HOST))
> > + return -ENODEV;
> > +
> > + bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
> > + if (!bridge)
> > + return -ENOMEM;
> > +
> > + if (!data->byte_access_allowed)
> > + bridge->ops = &cdns_ti_pcie_host_ops;
> > + rc = pci_host_bridge_priv(bridge);
> > + rc->quirk_retrain_flag = data->quirk_retrain_flag;
> > + rc->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
> > +
> > + cdns_pcie = &rc->pcie;
> > + break;
> > + case PCI_MODE_EP:
> > + if (!IS_ENABLED(CONFIG_PCIE_CADENCE_EP))
> > + return -ENODEV;
> > +
> > + ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> > + if (!ep)
> > + return -ENOMEM;
> > +
> > + ep->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
> > +
> > + cdns_pcie = &ep->pcie;
> > + break;
> > + default:
> > + dev_err(dev, "INVALID device type %d\n", mode);
> > + return 0;
> > + }
> > +
> > + cdns_pcie->dev = dev;
> > + cdns_pcie->ops = &j721e_pcie_ops;
> > +
> > pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > if (!pcie)
> > return -ENOMEM;
> >
> > + pcie->cdns_pcie = cdns_pcie;
> > pcie->mode = mode;
> > pcie->linkdown_irq_regfield = data->linkdown_irq_regfield;
> >
> > @@ -426,28 +464,6 @@ static int j721e_pcie_probe(struct platform_device *pdev)
> >
> > switch (mode) {
> > case PCI_MODE_RC:
> > - if (!IS_ENABLED(CONFIG_PCIE_CADENCE_HOST)) {
> > - ret = -ENODEV;
> > - goto err_get_sync;
> > - }
> > -
> > - bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
> > - if (!bridge) {
> > - ret = -ENOMEM;
> > - goto err_get_sync;
> > - }
> > -
> > - if (!data->byte_access_allowed)
> > - bridge->ops = &cdns_ti_pcie_host_ops;
> > - rc = pci_host_bridge_priv(bridge);
> > - rc->quirk_retrain_flag = data->quirk_retrain_flag;
> > - rc->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
> > -
> > - cdns_pcie = &rc->pcie;
> > - cdns_pcie->dev = dev;
> > - cdns_pcie->ops = &j721e_pcie_ops;
> > - pcie->cdns_pcie = cdns_pcie;
> > -
> > gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> > if (IS_ERR(gpiod)) {
> > ret = PTR_ERR(gpiod);
> > @@ -497,23 +513,6 @@ static int j721e_pcie_probe(struct platform_device *pdev)
> >
> > break;
> > case PCI_MODE_EP:
> > - if (!IS_ENABLED(CONFIG_PCIE_CADENCE_EP)) {
> > - ret = -ENODEV;
> > - goto err_get_sync;
> > - }
> > -
> > - ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> > - if (!ep) {
> > - ret = -ENOMEM;
> > - goto err_get_sync;
> > - }
> > - ep->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
> > -
> > - cdns_pcie = &ep->pcie;
> > - cdns_pcie->dev = dev;
> > - cdns_pcie->ops = &j721e_pcie_ops;
> > - pcie->cdns_pcie = cdns_pcie;
> > -
> > ret = cdns_pcie_init_phy(dev, cdns_pcie);
> > if (ret) {
> > dev_err(dev, "Failed to init phy\n");
> > @@ -525,8 +524,6 @@ static int j721e_pcie_probe(struct platform_device *pdev)
> > goto err_pcie_setup;
> >
> > break;
> > - default:
> > - dev_err(dev, "INVALID device type %d\n", mode);
> > }
> >
> > return 0;
>
>
>
> --
> greets
> --
> Christian Gmeiner, MSc
>
> https://christian-gmeiner.info/privacypolicy
