[PATCH v2] ARM: imx: fix error handling

Emil Goode
2014-05-16T23:18:55Z

Hello Uwe,

Thank you for the review.

On Fri, May 16, 2014 at 09:24:51PM +0200, Uwe Kleine-K?nig wrote:
> Hello Emil,
>
> IMHO the subject is too general. Maybe better use:
>
> ARM: imx: fix error handling in ipu device registration

Agreed, will change this and resend.

>
> On Fri, May 16, 2014 at 11:54:05AM +0200, Emil Goode wrote:
> > If we fail to allocate struct platform_device pdev we
> > dereference it after the goto label err.
> >
> > I have rearranged the error handling a bit to fix the issue
> > and also make it more clear.
> >
> > Signed-off-by: Emil Goode <emilgoode@gmail.com>
> > ---
> > v2: Changed to return -ENOMEM instead of ret where possible and
> > updated the subject line.
> >
> > arch/arm/mach-imx/devices/platform-ipu-core.c | 22 +++++++++++++---------
> > 1 file changed, 13 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm/mach-imx/devices/platform-ipu-core.c b/arch/arm/mach-imx/devices/platform-ipu-core.c
> > index fc4dd7c..68f2a4a 100644
> > --- a/arch/arm/mach-imx/devices/platform-ipu-core.c
> > +++ b/arch/arm/mach-imx/devices/platform-ipu-core.c
> > @@ -77,34 +77,38 @@ struct platform_device *__init imx_alloc_mx3_camera(
> >
> > pdev = platform_device_alloc("mx3-camera", 0);
> > if (!pdev)
> > - goto err;
> > + return ERR_PTR(-ENOMEM);
> >
> > pdev->dev.dma_mask = kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL);
> > if (!pdev->dev.dma_mask)
> > - goto err;
> > + goto put_pdev;
> >
> > *pdev->dev.dma_mask = DMA_BIT_MASK(32);
> > pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> >
> > ret = platform_device_add_resources(pdev, res, ARRAY_SIZE(res));
> > if (ret)
> > - goto err;
> > + goto free_dma_mask;
> >
> > if (pdata) {
> > struct mx3_camera_pdata *copied_pdata;
> >
> > ret = platform_device_add_data(pdev, pdata, sizeof(*pdata));
> > - if (ret) {
> > -err:
> > - kfree(pdev->dev.dma_mask);
> > - platform_device_put(pdev);
> > - return ERR_PTR(-ENODEV);
> > - }
> > + if (ret)
> > + goto free_dma_mask;
> > +
> > copied_pdata = dev_get_platdata(&pdev->dev);
> > copied_pdata->dma_dev = &imx_ipu_coredev->dev;
> > }
> >
> > return pdev;
> > +
> > +free_dma_mask:
> > + kfree(pdev->dev.dma_mask);
> > +put_pdev:
> > + platform_device_put(pdev);
> > +
> > + return ERR_PTR(ret);
> > }
> I didn't check if it is easily possible, but converting this file to use
> platform_device_register_full might simplify it considerably.

Will look into this and consider sending another patch.

>
> I'm not sure this fix is critical, because the problem happens if an
> allocation during boot fails. But still, if you want to get this fix
> into a stable release, you should simplify it, i.e. don't do the code
> reorganisations. (Also the "more clear" part seems to be subjective, I
> like the error handling better as it is now. But that might only be me.)

To my knowlege there is no impact on end users and I don't think the bug
is critical since, as you say, the allocation happens during boot.
Probably it's not necessary to have this fixed in stable kernels.

>
> Are you using this code? I thought arch/arm/mach-imx/devices to be dead
> as it is unused on dt platforms.

The bug was found using coccinelle. I'm not using the code and I don't know
what the plans are for this file in the transition to device tree. But as long
as the file is in the kernel I think it's worth fixing the bug.

Best regards,

Emil Goode

>
> Best regards
> Uwe
>
> --
> Pengutronix e.K. | Uwe Kleine-K?nig |
> Industrial Linux Solutions | http://www.pengutronix.de/ |