Re: [PATCH] Revert "usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default"

[Stephen Boyd]

Quoting Douglas Anderson (2021-12-07 09:43:41)
> This reverts commit cefdd52fa0455c0555c30927386ee466a108b060.
>
> On sc7180-trogdor class devices with 'fw_devlink=permissive' and KASAN
> enabled, you'll see a Use-After-Free reported at bootup.
>
> The root of the problem is that dwc3_qcom_of_register_core() is adding
> a devm-allocated "tx-fifo-resize" property to its device tree node
> using of_add_property().
>
> The issue is that of_add_property() makes a _permanent_ addition to
> the device tree that lasts until reboot. That means allocating memory
> for the property using "devm" managed memory is a terrible idea since
> that memory will be freed upon probe deferral or device unbinding.
>
> Let's revert the patch since the system is still functional without
> it. The fact that of_add_property() makes a permanent change is extra
> fodder for those folks who were aruging that the device tree isn't
> really the right way to pass information between parts of the
> driver. It is an exercise left to the reader to submit a patch
> re-adding the new feature in a way that makes everyone happier.
>
> Fixes: cefdd52fa045 ("usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default")
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---

Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>