Tracking the Blackout Bug

Alien54 writes "This earlier Slash story cited a CNN news report on how the August blackout was preventable. But, as seen in this Security Focus article, things are not so simple. 'In the initial stages, nobody really knew what the root cause was,' says Mike Unum, manager of commercial solutions at GE Energy. 'We test exhaustively, we test with third parties, and we had in excess of three million online operational hours in which nothing had ever exercised that bug,' says Unum. 'I'm not sure that more testing would have revealed that. Unfortunately, that's kind of the nature of software... you may never find the problem. I don't think that's unique to control systems or any particular vendor software.' Which leads to a number of other questions."

Comments

Re:For the 21st century...

[Raven42rac]

Yes, yes it is. If a mime gets hit by a tree in the forest, does anyone care? Sometimes, no matter how much testing you do, shit just happens. It is a fact of life. Show me one perfect, bug free, piece of software. Stuff breaks all the time, we only notice it when it affects us. We take for granted sometimes how good we have it. Power in this country is extremely reliable. We act as if a bomb dropped when the power goes out. Some parts of the world do not have power, clean water, etc. We should think of that before we start whining about having to actually talk to each other, use candles, read books, etc.

Testing isn't the answer...

[evilviper]

You can't expect just testing to reveal all bugs in a program. Even a simple program would have to be fed completely random data constantly, in every different order and circumstance concievable, for a very long time, to reveal all bugs. That's just not a real option.

The only way to have bug-free software is to write it properly. You have to modularize and simplify everything down to the point that each one is easilly understandable, and it is easy to detect when one is providing a sensless answer (in other words, cross-checking every result). Then, you have to tie them all together in a robust but simple way.

I know it's far easier to say it than do it, but it seems like nobody even tries to do it these days. Even mission-critical systems are commonly built as a single monolithic program, and when you have a lot of things going on within a single program, with no checks of the sanity of the data going into or comming out of each component, there is no way to be 100% certain that the program is theoretically and genuinely perfect. Meanwhile, by modularizing everything, you can PROVE that it is actually perfect.

But this is really just the old Macrokernel vs. Microkernel arguement all over again. A Microkernel can be perfect, while a macrokernel can never be completely bug-free, but people just find the latter to be easier to write, and then spend hundreds times more man-hours finding and removing bugs, rather than spending (less, overall) time doing it correctly in the first place.

Oh yes, almost forgot, IMHO...

Race conditions are nasty ...

[cagle_.25]

As you programmers all know, avoiding race conditions is really difficult. The fellow Neumann quoted in the article who said

But Peter Neumann, principal scientist at SRI International and moderator of the Risks Digest, says that the root problem is that makers of critical systems aren't availing themselves of a large body of academic research into how to make software bulletproof.

is overly optimistic; it's theoretically impossible to write a general test to find all race conditions in code. This is a variant of the Halting Problem.

Testing vs RTFS. Proprietary vs open.

[SharpFang]

if(int(rand()*1e20)==31337){
blow_up();
} else {
do_your_work();
}

Now I can't imagine amount of testing in proprietary software that could reveal this example of malicious code. In open source one look at the code will reveal it. Of course not all cases are so obvious, but always reading the code should be used together with "testing the software". How do you know lots of proprietary software that IS close-source isn't i.e. a gatweway for terrorists? How do you know biggest companies' stuff isn't all trojans? It wouldn't be hard to hide it. Say your software is kind of server. It does its job okay unless it receives TCP packets starting with certain string. Then it just executes commands contained after that string. Boom. No amount of -testing- will reveal this.
And there are bugs that can be triggered once in several billion cases. Only looking at the code could fix them and explaining "we did a lot of tests" is bullshit.
I put a lot of iron, gum, different materials, C4, glass and some more together and it goes, I call it "a car" and I rode 1000's of kilometers okay. Now no amount of testing in all road conditions will reveal it contains the C4 explosives. Looking under the hood will reveal it really fast.

"We test exhaustively..."

[Fratz]

Um, no you don't. By definition, if you tested exhaustively, you'd have found everything that could possibly go wrong with whatever you tested.

I'm not saying it's always feasible to test exhaustively, but don't say you did when you clearly didn't.

Also: "we had in excess of three million online operational hours in which nothing had ever exercised that bug"

Taken with the "exhaustively" statement, I'm thinking that whoever said these things doesn't understand QA very well. It's easy to write code that works well when everything's good, and it's often just as easy to test that. It's another thing entirely to write code that works well (or fails gracefully) when everything's wrong. And again, it's harder to test that.

Re:For the 21st century...

[evilviper]

Power in this country is extremely reliable.

Actually, that's statistically untrue. We have, perhaps, the least reliable power system in all the countries of the first-world. Sure, 3rd-world countries have worse-off power systems, but the comparison isn't valid at all.

Some parts of the world do not have power, clean water, etc. We should think of that before we start whining about having to actually talk to each other, use candles, read books, etc.

Since when does the hardship of others make an unreliable power system a plus? Some places may be worse, but so what? We pay a lot for power, and expect our money is being spent on making sure we DO NOT have many outages.

Meanwhile, in California, prices are high, and power was VERY unreliable. "Rolling Blackouts" anyone?

My point is this. If something is broken, we want to fix it. We don't want to sit around saying "Well, it isn't as broke as that one". If we do, pretty soon it will get worse, and worse, and worse, until we have no other countries to point at.

How about our medical system, and water utility? Should we accept thousands of deaths due to malpractice, or contaminated water, by just saying "Well, it's not as bad as country XYZ"? No, I don't think anyone would believe that, but it's really the same thing. Power outages do mean deaths, and do mean losses of lots of money. Businesses can't run, food can't be properly preserved, or even delivered. People die of heat-stroke, or hypothermia due to power loss. Ambulances can't get through dense traffic caused by traffic signals loosing power, etc.

A power outage is a lot more serious than people "whining" about not being able to watch TV... And yet you get moderated up anyhow... Amazing.

Re:Software bug was just one part of bigger proble

[Shakrai]

The software bug was just one piece of a much bigger problem; I wouldn't want to overstate its' role. There were many other factors; here are just a few:

Why don't we point out the real problem that likely caused this to happen. Energy deregulation in the first place.

I know I'll be jumped on by the free market types for daring to suggest this, but I'd rather have a regulated monopoly then a free-market for my life essential services anyday of the week. That article you linked is very interesting reading. Some quotes:

Prior to the implementation of Federal Energy Regulatory Commission Order 888, which greatly expanded electricity trading, the cost of electricity, excluding fuel costs, was gradually falling. However, after Order 888, and some retail deregulation, prices increased by about 10%, costing consumers $20 billion a year.

"Under the new system, the financial incentive was to run things up to the limit of capacity," explains Carreras. In fact, energy companies did more: they gamed the system. Federal investigations later showed that employees of Enron and other energy traders "knowingly and intentionally" filed transmission schedules designed to block competitors' access to the grid and to drive up prices by creating artificial shortages. In California, this behavior resulted in widespread blackouts, the doubling and tripling of retail rates, and eventual costs to ratepayers and taxpayers of more than $30 billion. In the more tightly regulated Eastern Interconnect, retail prices rose less dramatically.

In the four years between the issuance of Order 888 and its full implementation, engineers began to warn that the new rules ignored the physics of the grid. The new policies " do not recognize the single-machine characteristics of the electric-power network," Casazza wrote in 1998. "The new rule balkanized control over the single machine," he explains. "It is like having every player in an orchestra use their own tunes."

Equally important, the frequency stability of the grid rapidly deteriorated, with average hourly frequency deviations from 60 Hz leaping from 1.3 mHz in May 1999, to 4.9 mHz in May 2000, to 7.6 mHz by January 2001. As predicted, the new trading had the effect of overstressing and destabilizing the grid.

Of course it's the first quote that rings true with me. If deregulation is so friggen great then where is the cheap electric? Why can my Village sell me electric for $0.04/kWh with their regulated municipal power authority (while paying their workers Government rates and with Government benefits) when my girlfriend (who lives a whole two miles away) pays $0.14/kWh for electric supplied by a company that is supposedly part of the free market (a company that pays their employees crap and outsources their call center/billing functions to India). What's the problem with that picture?

Before energy deregulation the price of our electric was regulated by the PSC (Public Service Commission) and was fairly stable. The company that had the monopoly in this area made a set amount of profit (it wasn't a bad stock to pick up either -- you knew what you were getting), treated their employees well and charged a fair rate. Nowadays they treat their employees like crap, the stock has tanked because they are eating the price difference from their suppliers (otherwise we'd be paying about $0.20 kWh) and they are being raped by out of state suppliers that bought all of their generation capacity.

In another slightly related story the out of state company that bought one of their power plants sued the local township because they wanted the tax levy on the power plant reduced. They claimed that it wasn't worth what it used to be because they didn't plan on operating it (it was to be backup generation). After a three-year legal battle the township lost (ran out of money to pay the lawyers) and the tax levy was reduced by some 60%. Property and school taxes on

Re:The problem with SCADA systems

[miu]

For web development work I do I have a testing domain which is used to test sites to ensure that because they work here in my lab they will work when I hand them off to the client. Its 100% accurate, I've seen it done with countless other systems, so why wasn't it done here?

Mostly because web systems are still toys compared to real systems.

These systems get real and very intensive testing in labs as close to live as they can get. Even once they knew the conditions and affected subsystems it took the dev and testing teams months to recreate this bug in the lab. The lab is never just like real life, it cannot be - because even real life now is not always the real life of 10 seconds ago.

bugs are not inevitable

[ummit]

We test exhaustively... I'm not sure that more testing would have revealed that.

For an obscure race condition, this is undoubtedly true.

Unfortunately, that's kind of the nature of software... you may never find the problem.

This is sorta true, sorta false, and definitely misleading.

I don't think that's unique to control systems or any particular vendor software.

No, it's not unique; bugs that may never be found are rampant in most varieties of software. What's false -- tragically, crushingly false -- is the presumption that these unfindable bugs are therefore inevitable. They are not.

If there's a class of bugs that's hard to test for -- and of course there are many such classes -- the prudent thing to do is to find development methodologies that skirt those bugs entirely. If you don't put in so many bugs in the first place, you obviously don't have to work so hard trying to find and fix them.