| Message ID | 20210429110040.63119-1-colin.king@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [next] PCI: mediatek-gen3: Add missing null pointer check | expand |
Hi Colin, On Thu, 2021-04-29 at 12:00 +0100, Colin King wrote: > From: Colin Ian King <colin.king@canonical.com> > > The call to platform_get_resource_byname can potentially return null, so > add a null pointer check to avoid a null pointer dereference issue. > > Addresses-Coverity: ("Dereference null return") > Fixes: 441903d9e8f0 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192") > Signed-off-by: Colin Ian King <colin.king@canonical.com> > --- > drivers/pci/controller/pcie-mediatek-gen3.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c > index 20165e4a75b2..3c5b97716d40 100644 > --- a/drivers/pci/controller/pcie-mediatek-gen3.c > +++ b/drivers/pci/controller/pcie-mediatek-gen3.c > @@ -721,6 +721,8 @@ static int mtk_pcie_parse_port(struct mtk_pcie_port *port) > int ret; > > regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); > + if (!regs) > + return -EINVAL; Thanks for your patch. devm_ioremap_resource() will check and decode this null pointer dereference error, so I don't think we need to check here. Thanks. > port->base = devm_ioremap_resource(dev, regs); > if (IS_ERR(port->base)) { > dev_err(dev, "failed to map register base\n");
Le 29/04/2021 à 13:00, Colin King a écrit : > From: Colin Ian King <colin.king@canonical.com> > > The call to platform_get_resource_byname can potentially return null, so > add a null pointer check to avoid a null pointer dereference issue. > > Addresses-Coverity: ("Dereference null return") > Fixes: 441903d9e8f0 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192") > Signed-off-by: Colin Ian King <colin.king@canonical.com> > --- > drivers/pci/controller/pcie-mediatek-gen3.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c > index 20165e4a75b2..3c5b97716d40 100644 > --- a/drivers/pci/controller/pcie-mediatek-gen3.c > +++ b/drivers/pci/controller/pcie-mediatek-gen3.c > @@ -721,6 +721,8 @@ static int mtk_pcie_parse_port(struct mtk_pcie_port *port) > int ret; > > regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); > + if (!regs) > + return -EINVAL; > port->base = devm_ioremap_resource(dev, regs); > if (IS_ERR(port->base)) { > dev_err(dev, "failed to map register base\n"); > Nitpick: Using 'devm_platform_ioremap_resource_byname' is slightly less verbose and should please Coverity. Also, which git repo are you using? On linux-next ([1)], your proposed patch is already part of "PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192". [1]: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/drivers/pci/controller/pcie-mediatek-gen3.c CJ
On Thu, Apr 29, 2021 at 12:00:40PM +0100, Colin King wrote: > From: Colin Ian King <colin.king@canonical.com> > > The call to platform_get_resource_byname can potentially return null, so > add a null pointer check to avoid a null pointer dereference issue. > > Addresses-Coverity: ("Dereference null return") > Fixes: 441903d9e8f0 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192") > Signed-off-by: Colin Ian King <colin.king@canonical.com> > --- > drivers/pci/controller/pcie-mediatek-gen3.c | 2 ++ > 1 file changed, 2 insertions(+) Squashed into the commit it is fixing, in my pci/mediatek branch. Thanks, Lorenzo > diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c > index 20165e4a75b2..3c5b97716d40 100644 > --- a/drivers/pci/controller/pcie-mediatek-gen3.c > +++ b/drivers/pci/controller/pcie-mediatek-gen3.c > @@ -721,6 +721,8 @@ static int mtk_pcie_parse_port(struct mtk_pcie_port *port) > int ret; > > regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); > + if (!regs) > + return -EINVAL; > port->base = devm_ioremap_resource(dev, regs); > if (IS_ERR(port->base)) { > dev_err(dev, "failed to map register base\n"); > -- > 2.30.2 >
On Fri, Apr 30, 2021 at 09:47:06AM +0200, Christophe JAILLET wrote: > Le 29/04/2021 à 13:00, Colin King a écrit : > > From: Colin Ian King <colin.king@canonical.com> > > > > The call to platform_get_resource_byname can potentially return null, so > > add a null pointer check to avoid a null pointer dereference issue. > > > > Addresses-Coverity: ("Dereference null return") > > Fixes: 441903d9e8f0 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192") > > Signed-off-by: Colin Ian King <colin.king@canonical.com> > > --- > > drivers/pci/controller/pcie-mediatek-gen3.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c > > index 20165e4a75b2..3c5b97716d40 100644 > > --- a/drivers/pci/controller/pcie-mediatek-gen3.c > > +++ b/drivers/pci/controller/pcie-mediatek-gen3.c > > @@ -721,6 +721,8 @@ static int mtk_pcie_parse_port(struct mtk_pcie_port *port) > > int ret; > > regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); > > + if (!regs) > > + return -EINVAL; > > port->base = devm_ioremap_resource(dev, regs); > > if (IS_ERR(port->base)) { > > dev_err(dev, "failed to map register base\n"); > > > > Nitpick: > Using 'devm_platform_ioremap_resource_byname' is slightly less verbose > and should please Coverity. Not a nitpick at all. Jianjun is correct that devm_ioremap_resource() does check "regs" for NULL and it fails gracefully before trying to dereference it, so the extra check shouldn't be needed. And most cases in drivers/pci/ look like this, without the extra check: res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "app"); base = devm_ioremap_resource(dev, res); if (IS_ERR(base)) ... If devm_platform_ioremap_resource_byname() keeps Coverity happy, I think that's what we should be doing across drivers/pci/. Coverity false positives are a hassle. Seems like something for next cycle since we're in the middle of the merge window. > Also, which git repo are you using? On linux-next ([1)], your proposed patch > is already part of "PCI: mediatek-gen3: Add MediaTek Gen3 driver for > MT8192". > > [1]: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/drivers/pci/controller/pcie-mediatek-gen3.c I think this is because Lorenzo already squashed Colin's change in. Bjorn
On Fri, Apr 30, 2021 at 11:34:50AM -0500, Bjorn Helgaas wrote: > On Fri, Apr 30, 2021 at 09:47:06AM +0200, Christophe JAILLET wrote: > > Le 29/04/2021 à 13:00, Colin King a écrit : > > > From: Colin Ian King <colin.king@canonical.com> > > > > > > The call to platform_get_resource_byname can potentially return null, so > > > add a null pointer check to avoid a null pointer dereference issue. > > > > > > Addresses-Coverity: ("Dereference null return") > > > Fixes: 441903d9e8f0 ("PCI: mediatek-gen3: Add MediaTek Gen3 driver for MT8192") > > > Signed-off-by: Colin Ian King <colin.king@canonical.com> > > > --- > > > drivers/pci/controller/pcie-mediatek-gen3.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c > > > index 20165e4a75b2..3c5b97716d40 100644 > > > --- a/drivers/pci/controller/pcie-mediatek-gen3.c > > > +++ b/drivers/pci/controller/pcie-mediatek-gen3.c > > > @@ -721,6 +721,8 @@ static int mtk_pcie_parse_port(struct mtk_pcie_port *port) > > > int ret; > > > regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); > > > + if (!regs) > > > + return -EINVAL; > > > port->base = devm_ioremap_resource(dev, regs); > > > if (IS_ERR(port->base)) { > > > dev_err(dev, "failed to map register base\n"); > > > > > > > Nitpick: > > Using 'devm_platform_ioremap_resource_byname' is slightly less verbose > > and should please Coverity. > > Not a nitpick at all. Jianjun is correct that devm_ioremap_resource() > does check "regs" for NULL and it fails gracefully before trying to > dereference it, so the extra check shouldn't be needed. And most > cases in drivers/pci/ look like this, without the extra check: > > res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "app"); > base = devm_ioremap_resource(dev, res); > if (IS_ERR(base)) > ... > > If devm_platform_ioremap_resource_byname() keeps Coverity happy, I > think that's what we should be doing across drivers/pci/. Coverity > false positives are a hassle. Smatch knows that devm_ioremap_resource() will return ERR_PTR(-EINVAL) when we pass it a NULL. ;) regards, dan carpenter
diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c index 20165e4a75b2..3c5b97716d40 100644 --- a/drivers/pci/controller/pcie-mediatek-gen3.c +++ b/drivers/pci/controller/pcie-mediatek-gen3.c @@ -721,6 +721,8 @@ static int mtk_pcie_parse_port(struct mtk_pcie_port *port) int ret; regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac"); + if (!regs) + return -EINVAL; port->base = devm_ioremap_resource(dev, regs); if (IS_ERR(port->base)) { dev_err(dev, "failed to map register base\n");