On Mon, 18 Feb 2019 at 11:40, Geert Uytterhoeven geert@linux-m68k.org wrote:

Hi Krzysztof,

On Mon, Feb 18, 2019 at 11:27 AM Krzysztof Kozlowski krzk@kernel.org wrote:

...

The problem

Several device types (platform, amba, spi etc.) provide a driver_override field. On sysfs store or during device removal, they kfree() the existing value.

However the users are unaware of this and set the driver_override like:

    pdev->driver_override = "exynos5-subcmu";

which obviously leads to error.

IMHO driver_override is not meant to be set by a driver, only from userspace, for binding the device to vfio (is there another use case?).

...

clk: samsung: exynos5: Fix kfree() of const memory on setting driver_override slimbus: ngd: Fix kfree() of const memory on setting driver_override

I see all users set override immediately after allocating a platform device. Can't they just allocate a platform device using the override name instead? What am I missing?

For the clk-exynos5-subcmu.c case, driver registers several sub-devices. Each sub-devices is a clock controller associated with power domain. I guess the author wanted to have meaningful names of these sub-devices (DISP, CAM etc. like names of power domains), instead of just exynos5-subcmu.1, exynos5-subcmu.2 ...

If driver_override should not be used for such case, then I could replace it with what you said.

For the other uses of driver_override (drivers/rpmsg/rpmsg_internal.h and drivers/slimbus/qcom-ngd-ctrl.c) I don't know.

Best regards, Krzysztof