Re: [PATCH] binder: use standard functions to allocate fds

From: Christoph Hellwig
Date: Wed Aug 29 2018 - 03:00:43 EST


> config ANDROID_BINDER_IPC
> bool "Android Binder IPC Driver"
> - depends on MMU
> + depends on MMU && !CPU_CACHE_VIVT

Thats is a purely arm specific symbol which should not be
used in common code. Nevermind that there generally should
be no good reason for it.

> + fixup->offset = (uintptr_t)fdp - (uintptr_t)t->buffer->data;

This looks completely broken. Why would you care at what exact
place the fd is placed? Oh, because you share an array with fds
with userspace, which is a hell of a bad idea, and then maninpulate
that buffer mapped to userspace from kernel threads.

I think we just need to rm -rf drivers/android/binder*.c and be done
with it, as this piece of crap should never have been merged to start
with.