acc_release() attempts to synchronise with acc_open() using an atomic
'open_excl' member in 'struct acc_dev'. Unfortunately, acc_release()
prematurely resets this atomic variable to zero, meaning there is a
potential race on 'dev->disconnected':
acc_open() acc_release()
atomic_xchg(open_excl), 0)
atomic_xchg(open_excl, 1)
dev->disconnected = 0; dev->disconnected = 1;
Fix the race by ensuring that the 'disconnected' field is written
before clearing 'open_excl' in acc_release().
Bug: 173789633
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: Ib9a21f2305f6d70de3e760da62dbfdd66889200a
Signed-off-by: Giuliano Procida <gprocida@google.com>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.