Fix undefined behaviour in the USB controllers

[andrew]

Summary

The USB controller drivers assume they can cast a NULL pointer to a
struct and find the address of a member. KUBSan complains about this so
replace with the __offsetof macro that uses sither a builtin function
where available, or the same method on older compilers.

[• hselasky]

sys/dev/usb/controller/atmegadci.c

81

I would suggest to use __containerof() here to replace everything inside these macros BUS2SC macros.

__containerof(bus, struct atmegadci_softc, sc_bus)

Also make sure that all build targets inside stand/usb are building after this change.

[andrew]

Use __containerof

[• hselasky]

And update the commit message with the containerof bits.

[andrew]

I already changed it locally, unfortunately it doesn't update the review automatically.

sys/dev/usb/controller/atmegadci.c

81

Is stand/usb used by any of the loaders? It's broken for me on arm64, e.g. bus_topo_lock is undefined in usb_controller.c

[• hselasky]

I'll have a look at stand/usb later then.

It is not used by any official loaders.

Is stand/usb used by any of the loaders? It's broken for me on arm64, e.g. bus_topo_lock is undefined in usb_controller.c

@imp : Do you mind adding two dummy functions bus_topo_lock() and bus_topo_unlock() to the kernel emulation shims in stand/usb ?

[andrew]

There are a few other errors I've seen when building with make -k