Re: [PATCH] usb: mon: make mmapped memory read only

[Dmitry Vyukov]

Hi Tadeusz,

Looking at places like these:
https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/infiniband/hw/qib/qib_file_ops.c#L736
https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/infiniband/hw/mlx5/main.c#L2088
I think we also need to remove VM_MAYWRITE, otherwise it's still
possible to turn it into a writable mapping with mprotect.

It's also probably better to return an error if VM_WRITE (or VM_EXEC?) is set
rather than silently fix it up.