rcu_read_unlock_special is undefined

[Alberto Milone]

As per the topic, rcu_read_unlock_special is exposed but can't really be used.

rcu_read_unlock_special defined in kernel/rcutiny_plugin.h and defined as a function prototype in include/linux/rcupdate.h as follows:
extern void rcu_read_unlock_special(struct task_struct *t);

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: linux-image-3.8.0-12-lowlatency 3.8.0-12.8
ProcVersionSignature: Ubuntu 3.8.0-12.8-lowlatency 3.8.2
Uname: Linux 3.8.0-12-lowlatency x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.8-0ubuntu1
Architecture: amd64
Date: Tue Mar 12 12:44:34 2013
InstallationDate: Installed on 2011-08-17 (572 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110817)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-lowlatency
UpgradeStatus: Upgraded to raring on 2012-01-11 (425 days ago)

[Alberto Milone (albertomilone)]

Here's what happens if I try to use the function from the broadcom driver

[Alberto Milone (albertomilone)]

This is the patch that I've written in order to get the broadcom driver to build with linux-lowlatency 3.8

[Andy Whitcroft (apw)]

This was worked-around in the binary driver consuming it.