Messages in this thread Patch in this message | | | Date | Tue, 31 Jan 2017 12:22:32 -0600 | From | Bjorn Helgaas <> | Subject | Re: [PATCH] Pci: host - Fix possible NULL derefrence. |
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On Tue, Jan 31, 2017 at 09:09:00AM -0600, Bjorn Helgaas wrote: > Hi Shailendra, > > On Mon, Jan 30, 2017 at 10:19:35AM +0530, Shailendra Verma wrote: > > of_match_device could return NULL, and so can cause a NULL > > pointer dereference later. > > > > Signed-off-by: Shailendra Verma <shailendra.v@samsung.com> > > --- > > drivers/pci/host/pcie-hisi.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/pci/host/pcie-hisi.c b/drivers/pci/host/pcie-hisi.c > > index 56154c2..3256f8f 100644 > > --- a/drivers/pci/host/pcie-hisi.c > > +++ b/drivers/pci/host/pcie-hisi.c > > @@ -174,6 +174,10 @@ static int hisi_pcie_probe(struct platform_device *pdev) > > driver = dev->driver; > > > > match = of_match_device(driver->of_match_table, dev); > > + if (!match) { > > + dev_err(dev, "Error: No device match found\n"); > > + return -ENODEV; > > + } > > hisi_pcie->soc_ops = (struct pcie_soc_ops *) match->data; > > > > hisi_pcie->subctrl = > > I like this patch and I think it's correct. I'd like an ack from Zhou > and/or Gabriele, and I'd propose the following tweak, which just moves the > check earlier, before we start allocating this:
Geert pointed out in a similar case that it's actually impossible for match to be NULL here because the only way to call hisi_pcie_probe() is to match an entry in hisi_pcie_of_match[]. So I think the following patch is even better because it removes a mention of driver->of_match_table. I can't easily build test to be sure, but I think the cast is also unnecessary.
commit 806d19760e48166505818d4efafbdfbad5810989 Author: Shailendra Verma <shailendra.v@samsung.com> Date: Mon Jan 30 10:19:35 2017 +0530
PCI: hisi: Use of_device_get_match_data() to simplify probe
The only way to call hisi_pcie_probe() is to match an entry in hisi_pcie_of_match[], so match cannot be NULL.
Use of_device_get_match_data() to retrieve the soc_ops pointer. No functional change intended.
[bhelgaas: use of_device_get_match_data(), changelog] Based-on-suggestion-from: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Shailendra Verma <shailendra.v@samsung.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/host/pcie-hisi.c b/drivers/pci/host/pcie-hisi.c index a301a7187b30..34d10d242225 100644 --- a/drivers/pci/host/pcie-hisi.c +++ b/drivers/pci/host/pcie-hisi.c @@ -259,7 +259,6 @@ static int hisi_pcie_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct hisi_pcie *hisi_pcie; struct pcie_port *pp; - const struct of_device_id *match; struct resource *reg; struct device_driver *driver; int ret; @@ -272,11 +271,10 @@ static int hisi_pcie_probe(struct platform_device *pdev) pp->dev = dev; driver = dev->driver; - match = of_match_device(driver->of_match_table, dev); - hisi_pcie->soc_ops = (struct pcie_soc_ops *) match->data; + hisi_pcie->soc_ops = of_device_get_match_data(dev); hisi_pcie->subctrl = - syscon_regmap_lookup_by_compatible("hisilicon,pcie-sas-subctrl"); + syscon_regmap_lookup_by_compatible("hisilicon,pcie-sas-subctrl"); if (IS_ERR(hisi_pcie->subctrl)) { dev_err(dev, "cannot get subctrl base\n"); return PTR_ERR(hisi_pcie->subctrl);
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