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Intel Skylake Bug Causes PCs To Freeze During Complex Workloads (arstechnica.com)
chalsall writes: Intel has confirmed an in-the-wild bug that can freeze its Skylake processors. The company is pushing out a BIOS fix. Ars reports: "No reason has been given as to why the bug occurs, but it's confirmed to affect both Linux and Windows-based systems. Prime95, which has historically been used to benchmark and stress-test computers, uses Fast Fourier Transforms to multiply extremely large numbers. A particular exponent size, 14,942,209, has been found to cause the system crashes. While the bug was discovered using Prime95, it could affect other industries that rely on complex computational workloads, such as scientific and financial institutions. GIMPS noted that its Prime95 software "works perfectly normal" on all other Intel processors of past generations."
Old-timers will remember the Pentium 5 FDIV bug where the chip sometimes yielded incorrect results for complex mathematical calculations.
Hulk SMASH Celiac Disease
Too bad AMD is out of PC CPU race and Intel will got unpunished for such major flaw.
It doesn't matter how complex the task needs to be to trigger the bug. Once it's there, it's there.
It probably just means the NSA is already using your processor's compute capacity as part of their vast decryption botnet. The fix should improve resource management so you won't notice it in future.
Ok, they missed some test vector. Quite bad, but at this complexity level not so surprising.
Will they resolve this by microcode update at the cost of some instruction(s) being slower? Let's bet.
A minor bug causes processor to not-process.
Intel is suggesting a tentative fix as follows:
- Locate the power button.
- Switch the computer off.
- Go outside and play badminton.
I no longer have access to an Intel code name Secret decoder ring. Can someone me what the public marketing name is for Skylake?
This is a really interesting talk from 32c3 detailing the challenges involved in designing and verifying something as complex as a CPU where it can only be simulated at 1 Hz and costs 5 million to produce silicon for testing. https://www.youtube.com/watch?v=eDmv0sDB1Ak. The level of difficulty on getting this right just blows my mind. If it weren't for economies of scale CPU's would be completely out of reach. Also interesting in the talk is the vast number of CPU defects that are found and cataloged that most people appear to be unaware of. Most are of little importance (and hence don't get fixed), but some are fixed via code (as in this case), but there is no guarantee that these are being patched by OEM's.
Just got a MSI with 32GB of RAM and the skylake processor because I need to manipulate large Autocad files. For no reason my laptop would lock up and nothing would be in the dump logs. I could not figure it out...until now.
Isn't it easier to distibute new firmware with microcode_ctl/intel-microcode packages? MS-Windows also seems to have some such package updates.
The CPU makes the PC freeze? If they could just crank this bug down a bit it could revolution the server cooling industry.
lucm, indeed.
Just saw this video
https://www.youtube.com/watch?v=eDmv0sDB1Ak
Gives some insight in to the insanely complex nature of processor design and how absurdly reliable they need to be. Modern computers pretty much expect the CPU to be flawless and that's a daunting task considering their complexity and the staggering amount of computations they perform even in ordinary day-to-day use.
An error that occurs one in a billion operations will happen 3 times a second at 3ghz.
So yeah. Some bugs are gonna happen. Thankfully most can be fixed with microcode updates.
Back in the days of the FDiv bug, Intel did not do a good job of disclosing bugs in their CPU's. The pressure kept mounting on them to both fix the bug (and to provide a mechanism for system and software vendors to know they are there in the first place), but they stubbonly refused to do the right thing. So, a columnist for PCWeek (I think it was Dave Berlind) wrote a front page article about the issue. I told him I had canceled the PC orders I placed and would not buy more of them until the situation was resolved. A short while later, Intel changed their tune and also started being more open with the bugs in their processors (PS: we didn't mention that my canceled PC order was for 3 PC's!!! - not exactly dishonest as it was true and was probably representative of most tech people back then, but kind of funny.)
indeed. Streng was bold.
http://blogs.sciencemag.org/pipeline/archives/2010/02/23/things_i_wont_work_with_dioxygen_difluoride
see also
https://what-if.xkcd.com/40/
"I am Pentium of Intel, SIN will be approximated."
"I am Skylake of Int..."
"B.. B... B.. Bulldozer!"
Well, count my lucky stars that OS X isn't affected! Mac master race wins again! I'm guessing there's no Prime95 mac users, so therefore I must be safe, right? right?
On a slightly more serious note, how does one bios-update the CPU on a Mac? Does Apple roll it into their updates? Just curious.
It's sentient.
It knows not to fsck with E40001
Though of course, being Apple, they won't admit they have one.
You can have concurrent workloads writing to a HFS+ Journal volume all day long and have no problems - even though it sucks about 20% kernel time. As soon as the CPU gets starved for cycles by user processes (think something like transcoding) a race condition rears its ugly head, OSX panics, and suddenly users see the infamous "Disk not ejected properly" error message. OSX then dutifully remounts the volume and the journal rollback erases all uncommitted file and folder changes. Thanks, Apple!
and run simultaneously on 7.9335 threads, too!
if this is supposed to be a new economy, how come they still want my old fashioned money?
This is awesome!. I so rarely get a chance to use the phrase correlation != causation on Slashdot! (Also, I have some awesome swamp^H^H^H^H^Hland for sale, cheap!)
Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
Correct, but for the wrong reason:
There are currently no Apple products that utilize a Skylake CPU.
I was incorrect. The 2015 iMac has a Skylake CPU.
How exactly does one use "Fast Fourier Transforms to multiply extremely large numbers" and when exactly did Prime95 become an industry?
as someone who may have worked on that chip, I am enormously grateful that it is not my shitstorm to clean up.
Comment removed based on user account deletion
I think GIMPS means "works perfectly normally." ESL students and kids who didn't pass High School English shouldn't really be talking to the press, eh?
Most processor bugs have nothing to do with the frequency of execution, they're caused by a unique set of circumstances. So when someone says it will happen once out of every billion operations they're making the assumption that you will setup that unique case one out of every billion times. This depends heavily on what you're doing with processor. For example, this bug is a math related operation and chances are that if you put it in one of Google or Netflix web servers it would never hit the bug for the duration of it's use even though its getting hammered... because they're not doing math operations of this nature. However, a math major may hit it 2-3 times a week doing their homework (I was in college during the FDIV bug, my g/f at the time was an engineering student who had a statics simulation that triggered it... I thought it was cool... she did not :p)
While the bug was discovered using Prime95, it could affect other industries that rely on complex computational workloads, such as scientific and financial institutions.
How about porn?
Please login to access my lawn
Oh, I know, but I think it is more a case of one more straw to break the camel's back. Back then, PCWeek was a BIG DEAL, and I would be very surprised if it didn't add a significant amout of pressure to the people making the decisions at Intel. Regardless of whether it did or not though, the main thing I was happy about was not the actual recall they did, but rather the fact that they implemented a program to disclose bugs for the CPU's they created going forward (because face it, anything as complicated as a "modern" CPU is going to have some flaws.)
Could this be an attempt to break crypto currency?
I told him I had canceled the PC orders I placed and would not buy more of them until the situation was resolved. A short while later, Intel changed their tune and also started being more open with the bugs in their processors
Before I was born, Britain had never had a female prime minister, America had never had a black president, and the Shah still ruled Iran.
My birth clearly changed all of this...
systemd is Roko's Basilisk.
weapons of math destruction. 3
you insensitive clod!