[PATCH] soc: ti: pruss: fix return check for of_device_get_match_data()

[Lee Jones]

On Tue, 10 Nov 2020, Grzegorz Jaszczyk wrote:

> Hi
> 
> On Tue, 10 Nov 2020 at 02:31, Luo Meng <luomeng12 at huawei.com> wrote:
> >
> > of_device_get_match_data() maybe return NULL pointer which cannot
> > be checked with IS_ERR.
> >
> > Fixes: ba59c9b43c86 ("soc: ti: pruss: support CORECLK_MUX and IEPCLK_MUX")
> > Reported-by: Hulk Robot <hulkci at huawei.com>
> > Signed-off-by: Luo Meng <luomeng12 at huawei.com>
> > ---
> >  drivers/soc/ti/pruss.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
> > index cc0b4ad7a3d3..582f48051c30 100644
> > --- a/drivers/soc/ti/pruss.c
> > +++ b/drivers/soc/ti/pruss.c
> > @@ -126,7 +126,7 @@ static int pruss_clk_init(struct pruss *pruss, struct device_node *cfg_node)
> >         int ret = 0;
> >
> >         data = of_device_get_match_data(dev);
> > -       if (IS_ERR(data))
> > +       if (!data)
> >                 return -ENODEV;

Also this would miss any errors, leading to dereference issues.

I think what you meant was IS_ERR_OR_NULL(), but this would still be
incorrect for the reasons Grzegorz mentions below.

> >         clks_np = of_get_child_by_name(cfg_node, "clocks");
> > @@ -175,7 +175,7 @@ static int pruss_probe(struct platform_device *pdev)
> >         const char *mem_names[PRUSS_MEM_MAX] = { "dram0", "dram1", "shrdram2" };
> >
> >         data = of_device_get_match_data(&pdev->dev);
> > -       if (IS_ERR(data)) {
> > +       if (!data) {
> 
> Thank you for your interest but with your patch the driver will not be
> functional anymore for all devices without match data (e.g.
> "ti,am3356-pruss") which is not what we want. The proper fix was
> already posted end of October:
> https://patchwork.kernel.org/project/linux-arm-kernel/patch/20201026144943.30821-1-grzegorz.jaszczyk@linaro.org/
> 
> Thank you,
> Grzegorz

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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