Over the last years, many fixes and changes have been applied to
Binder in the Linux kernel, but these fixes were never backported
to anbox-modules. The meant that the version of Binder in anbox-modules
was very outdated.
With this commit, Binder has been update to the latest state from
the Linux kernel. This should also fix the compile on kernel 5.12
and later.
On kernel 5.7 and later, kallsyms_lookup_name() can no longer be called from a kernel
module for reasons described here: https://lwn.net/Articles/813350/
As binder really needs to use kallsysms_lookup_name() to access some kernel
functions that otherwise wouldn't be accessible, KProbes are used on later
kernels to get the address of kallsysms_lookup_name(). The function is
afterwards used just as before. This is a very dirty hack though and the much
better solution would be if all the functions that are currently resolved
with kallsysms_lookup_name() would get an EXPORT_SYMBOL() annotation to
make them directly accessible to kernel modules.
Christian Hoff