Feeds

Linux police offer deviant Android return from exile

Google, you have three options...

Top three mobile application threats

OSCON Linux kernel maintainers have offered Google three ways of returning Android into their good graces.

Google's options for re-admission to the kernel are: put the stubs of Android's wait locks into the main kernel, introduce Android's wait locks as PMQOS constraints, or adopt a patch written by a Linux kernel maintainer that would re-implement wait locks in a "socially acceptable way".

Android was booted from the Linux kernel when its drivers were deleted last year. It was claimed that nobody cared about the Android kernel code and that Google had made kernel integration difficult with a "sometimes bizarre" security model.

Linux kernel SCSI subsystem maintainer James Bottomley told The Reg that it's up to Google to decide which of the three ways back it prefers. "We need their feedback on the three options," Bottomley told us at the O'Reilly Open-Source Convention in Portland, Oregon.

Google said it has offered Android code for inclusion in the next version of the Linux kernel – version 2.6.34 – but these failed to materialize in the first release candidate.

Google open source programs manager Chris DiBona told The Reg that Google is now "hanging" and the fact its changes didn't make RC1 makes him doubt they'll be included in the final version of 2.6.34 at all.

DiBona said at OSCON: "We are still talking to them [kernel maintainers] – we'll see what happens. We want to be in there. It will open up a lot of devices to the kernel."

He's right to be doubtful. It seems Google's fix was shot down by kernel maintainers in the PMQOS sub system. They objected to hacking the kernel to facilitate changes designed for mobile devices.

The fix appears to have been the result of talks between Google and kernel maintainers at this year's Linux Collaboration Summit in San Francisco, California.

Google had proposed a set of suspend locks – actions that intervened in the race around the phone's system during shut down process in response to an incoming call. The suspend locks were designed to stop shut down so that the user doesn't miss their call.

"Although the sleep and suspend is very elegant, it introduced wait locks to get around the race problem and the kernel developers were not happy with the fact it's a hack around for a lot of races that got introduced into the infrastructure," Bottomley said.

Now, there are the three options on the table awaiting Google's approval.

Stubs would be a temporary measure that could do more harm than good. Developers could compile code to either the main kernel or the Android kernel, creating confusion. Stubs are used in programming to simulate functionality and are used when targeting different platforms.

In a further twist, stubs would be removed from Linux after a period of nine months if there's no permanent fix adding to the confusion.

"Stubs is a bit more dangerous because if nothing happens after a certain time the period stubs approach will get thrown out," Bottomley said.

Bottomley favored the PMQOS or full patch options. Modifications have already been written for the PMQOS subsystem that tackles locks so code's ready to go. The patch, meanwhile, would also perform locks but using what Bottomley called a more "socially acceptable way" – presumably keeping maintainers happy. Android would need to accept these changes, though.

"I'd like to see it sorted out fully... but we need Google to comment fully [on the proposals]," Bottomley said. ®

Maximizing your infrastructure through virtualization

More from The Register

next story
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
NO MORE ALL CAPS and other pleasures of Visual Studio 14
Unpicking a packed preview that breaks down ASP.NET
Captain Kirk sets phaser to SLAUGHTER after trying new Facebook app
William Shatner less-than-impressed by Zuck's celebrity-only app
Mozilla fixes CRITICAL security holes in Firefox, urges v31 upgrade
Misc memory hazards 'could be exploited' - and guess what, one's a Javascript vuln
Apple fanbois SCREAM as update BRICKS their Macbook Airs
Ragegasm spills over as firmware upgrade kills machines
Cheer up, Nokia fans. It can start making mobes again in 18 months
The real winner of the Nokia sale is *drumroll* ... Nokia
EU dons gloves, pokes Google's deals with Android mobe makers
El Reg cops a squint at investigatory letters
Chrome browser has been DRAINING PC batteries for YEARS
Google is only now fixing ancient, energy-sapping bug
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.