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Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

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Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#81

Post by ashelmire »

dsign wrote: post #19

This is a clusterf /big deal. Beyond the security implications, it means that all companies paying for computing resources will have to pay roughly 30% more overnight on cloud expenses for the same amount of CPU, assuming that they can just scale up their infrastructure. I know that bugs happen and that there was nothing intentional on this one, but at times like this is hard to held at bay the temptation of claiming…

From what I've read, this slowdown only affects syscalls, which, since they aren't usually a huge percentage of processing in the first place, should not have such an effect. You're more likely looking at a few percent at most, which is not going to be enough to make AMD outperform Intel. Let's stop the fear mongering and wait for actual metrics.

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#82

Post by 0xcde4c3db »

dsign wrote: post #49

Here are some numbers quantifying the problem. Big caveats apply as they are very preliminary, but the hit due to the software patches looks extremely significant: https://www.phoronix.com/scan.php?page=article&item=linux-41...

Superficially, it seems like the performance hit mostly scales with IOPS or transactions per second, which might have some pretty serious implications for performance/dollar in the kinds of intensive back-end applications where Intel currently dominates and AMD is trying to make inroads with EPYC.

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#83

Post by twoodfin »

pcwalton wrote: post #67
rayiner wrote: post #52

Can someone help me understand why this is such a big deal? This doesn’t seem to be a flaw in the sense of the Pentium FDIV bug where the processor returned incorrect data. It doesn’t even seem to be a bug at all, but a side channel attack that would be almost expected in a processor with speculative execution unless special measures were taken to prevent it. And it doesn’t seem like it can be used for privilege esca…

Reading secret data out of kernel memory is very bad on cloud environments. Keep in mind that the kernel deals with a lot of cryptography.

Is there anything this bug can give you that you can't get with

    sudo cat /dev/mem
?

I'm having a hard time understanding why this is worse than any other local root escalation bug except for the consequences of the necessary patch.

EDIT: I see that /dev/mem is no longer a window on all of physical RAM in a default secure configuration. Is it true that there's no way for root to read kernel memory in a typical Linux instance? If so, the severity of this issue makes more sense to me.

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#84

Post by mizzack »

dzink wrote: post #20

Didn’t the Intel CEO just sell half of his shares/options? If he knew about these issues isn’t that illegal?

Looks like Krzanich sold $39.4M of stock on 11/28. Hard to say when the top brass knew about this flaw.

https://finance.yahoo.com/quote/INTC/insider-transactions?p=...

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#85

Post by ihsw2 »

rwmj wrote: post #5

AMD must be pretty happy about this patch: https://lkml.org/lkml/2017/12/27/2

Not quite -- without his patch, the performance penalty will hit them too. Tom is proposing to be excluded from the proposed solution as it would hit AMD with collateral damage from the `X86_BUG_CPU_INSECURE` fix.

I'm sure there are frantic emails claiming that AMD shouldn't be punished for Intel's mistake.

EDIT: actually the fix will go out with 4.14.12 and 4.15rc7, both `X86_BUG_CPU_INSECURE` and AMD's addendum to be protected from the collateral damage.

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#86

Post by mikeash »

rayiner wrote: post #52

Can someone help me understand why this is such a big deal? This doesn’t seem to be a flaw in the sense of the Pentium FDIV bug where the processor returned incorrect data. It doesn’t even seem to be a bug at all, but a side channel attack that would be almost expected in a processor with speculative execution unless special measures were taken to prevent it. And it doesn’t seem like it can be used for privilege esca…

If “reading secret data out of kernel memory” translates into “read the page cache from a stranger’s VM that happens to be on the same cloud server” then this could be worse than Heartbleed.

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#87

Post by mschaef »

ashelmire wrote: post #81
dsign wrote: post #19

This is a clusterf /big deal. Beyond the security implications, it means that all companies paying for computing resources will have to pay roughly 30% more overnight on cloud expenses for the same amount of CPU, assuming that they can just scale up their infrastructure. I know that bugs happen and that there was nothing intentional on this one, but at times like this is hard to held at bay the temptation of claiming…

From what I've read, this slowdown only affects syscalls, which, since they aren't usually a huge percentage of processing in the first place, should not have such an effect. You're more likely looking at a few percent at most, which is not going to be enough to make AMD outperform Intel. Let's stop the fear mongering and wait for actual metrics.

> syscalls, which, since they aren't usually a huge percentage of processing in the first place... Let's stop the fear mongering

Agreed!

(We should probably also stop overgeneralizing about the nature of computational workloads.)

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#88

Post by mikeokner »

emn13 wrote: post #27

This piece is (IMNSHO) trash. It's trying to stare into some crystal ball guessing at the cause of market fluctuations; but there's no real evidence they're right. Not to mention it's pretty misleading about technical stuff, saying e.g. "Chip design errors are exceedingly rare. More than 20 years ago, a college professor discovered a problem with how early versions of Intel’s Pentium chip calculated numbers." So, the…

Bloomberg? Trash? I'm shocked (I'm not).

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#89

Post by vardump »

ashelmire wrote: post #81
dsign wrote: post #19

This is a clusterf /big deal. Beyond the security implications, it means that all companies paying for computing resources will have to pay roughly 30% more overnight on cloud expenses for the same amount of CPU, assuming that they can just scale up their infrastructure. I know that bugs happen and that there was nothing intentional on this one, but at times like this is hard to held at bay the temptation of claiming…

From what I've read, this slowdown only affects syscalls, which, since they aren't usually a huge percentage of processing in the first place, should not have such an effect. You're more likely looking at a few percent at most, which is not going to be enough to make AMD outperform Intel. Let's stop the fear mongering and wait for actual metrics.

> From what I've read, this slowdown only affects syscalls

Incorrect. It also affects interrupts and (page) faults.

Any usermode to kernel and back transition.

Re: Intel Confronts Potential ‘PR Nightmare’ With Reported Chip Flaw

#90

Post by pavel_lishin »

> AMD shares surged as much as 7.2 percent to $11.77 Wednesday. Intel fell as much as 3.8 percent, the most since April, to $45.05. An Intel spokesman declined to comment.

I have no real context for this, but is 7.2% considered a "soar"? And a 3.8% decrease seems like kind of not a lot, considering what's fucking happening here.

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