Arnd Bergmann 4184da4f31 staging: vchiq: fix __user annotations
My earlier patches caused some new sparse warnings, but it turns out
that a number of those are actual bugs, or at least suspicous code.

Adding __user annotations to the data structures that are defined in
uapi headers helps avoid the new warnings, but that causes a different
set of warnings to show up, as some of these structures are used both
inside of the kernel and at the user interface but storing pointers to
different things there.

Duplicating the vchiq_service_params and vchiq_completion_data structures
in turn takes care of most of those, and then it turns out that there
is a 'data' pointer that can be any of a __user address, a dmd_addr_t
and a kernel pointer in vmalloc space at times.

I'm trying to annotate these as best I can without changing behavior,
but there still seems to be a serious bug when user space passes
a valid vmalloc space address instead of a user pointer. Adding
comments in the code there, and leaving the warnings in place that
seem to correspond to actual bugs.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200925114424.2647144-1-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-25 14:34:03 +02:00
2020-09-14 06:57:52 +02:00
2020-09-13 16:06:00 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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