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Meltdown Update Kernel doesnt boot

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Re: Meltdown Update Kernel doesnt boot

#101

Post by em3rgent0rdr »

morganvachon wrote: post #54
em3rgent0rdr wrote: post #29

Earlier quoted context omitted.

even if it affects all speculative CPUs, if this happened in the car world, all the cars would be recalled. Not saying that is practical in computer world...just continuing with the analogy. Spectre/Meltdown is a wakeup call for many things, one of them probably being for computer manufacturers to not solder the CPU to the Motherboard and for the x86 world to stick with a standard socket, to facilitate replacing part…

> "Spectre/Meltdown is a wakeup call for many things, one of them probably being for computer manufacturers to not solder the CPU to the Motherboard" Good luck with that. A large portion of affected CPUs/SoCs are in mobile devices and ultrabooks. Socketed chips simply won't fly in those kinds of devices.

Alternatively, even if the boards + CPU are tightly integrated, if used a particular standard like EOMA-68, then they could be easily replaced with rest of desktop/laptop/phone not being affected.

https://www.crowdsupply.com/eoma68/micro-desktop

Re: Meltdown Update Kernel doesnt boot

#103

Post by jlgaddis »

ams6110 wrote: post #82
bproven wrote: post #64

Earlier quoted context omitted.

AFAIK worse case you should be able to select the previous kernel in grub2 upon reboot. It just hangs after grub on this (bad) kernel I think...

Yeah but if you have a couple of hundred machines that aren't booting.... That's pretty worst case.

That is pretty worst case. OTOH, it teaches the lesson about testing updates on a small number of hosts before rolling 'em out globally.

One has to learn that lesson at some point.

Re: Meltdown Update Kernel doesnt boot

#105

Post by cpncrunch »

rincebrain wrote: post #100
otakucode wrote: post #83

Earlier quoted context omitted.

For AMD chips, yes. Yesterday Microsoft announced they were suspending rolling out updates to certain AMD chips because it was resulting in non-bootable systems. I didn't read the technical details so I can not say whether it was specifically BIOS-related. Both a total non-booting state and BSODs were mentioned in the article I saw (from general press, so might have been garbage, sorry).

Microsoft's claim was "Microsoft has determined that some AMD chipsets do not conform to the documentation previously provided to Microsoft to develop the Windows operating system mitigations to protect against the chipset vulnerabilities known as Spectre and Meltdown"[1], and their docs simply suggest asking AMD for more details[2]. So it sounds like it was probably specific chipsets and not CPUs, but who knows. [1]…

It happened to one of my HP boxes that has an AMD chipset. After installing the update, windows 10 just hangs at the blue windows logo. Only solution is to turn the machine off and on twice, which then results in it undoing the update.

The Microsoft link you provide says "Microsoft is working with AMD to resolve this issue", so they're not just brushing it off and telling customers to contact AMD.

Re: Meltdown Update Kernel doesnt boot

#106

Post by pubby »

drb91 wrote: post #99
cratermoon wrote: post #88

Earlier quoted context omitted.

A null pointer doesn't hold a reference, though.

It does if you have something at 0x0. Or, to put it another way, I have no clue to what you're referring--what do references have to do with "The Billion Dollar Mistake"[0]? [0]: https://en.wikipedia.org/wiki/Tony_Hoare#Apologies_and_retra... EDIT: my apologies, that joke was actually pretty good.

What modern systems even map memory to 0x0? Doing so breaks the C standard, among other things.

Re: Meltdown Update Kernel doesnt boot

#107

Post by Nacraile »

bArray wrote: post #43
nabilt wrote: post #41

I just updated my Dell, but haven't restarted. Do we know how widespread the problem is and should I roll back the update?

I would suspend your machine until we find out more, I have the same problem.

You all do realize that (at least by default) ubuntu will keep old kernel versions around, and you can choose to boot them in GRUB, don't you?

This is certainly a pain, but it's hardly the first time a broken kernel has shipped. Reasonable recovery mechanisms are in place.

Re: Meltdown Update Kernel doesnt boot

#108

Post by rlanday »

Consultant32452 wrote: post #80
_Nat_ wrote: post #55

Earlier quoted context omitted.

Are you suggesting that we recall the great bulk of modern CPU's? Like, literally gut everyone's computers, including those in data centers and running critical infrastructure, until replacements are eventually manufactured? Or did you mean something else?

Boxed Intel processors carry a 3 year warranty. It certainly seems reasonable for everyone who bought a CPU within the last 3 years to expect a warranty replacement with the manufacturer defect fixed. In the EU virtually every product comes with a 2 year warranty. So every CPU sold in the EU in the last two years should be replaced for free by Intel, even through OEMs. I wonder what potential class action lawsuits In…

Any sufficiently complex CPU surely contains some number of defects, perhaps even serious security defects, just as any sufficiently complex piece of software contains bugs and security holes. I wouldn't be surprised if someone tries to sue Intel over this, or even if they win, but this is way outside the scope of what a warranty would traditionally cover, which in the case of a CPU would be hardware failure. If a warranty had to cover every possible defect, a bunch of people would be constantly trying to get free CPUs out of Intel every time they updated their errata:

https://www.intel.com/content/dam/www/public/us/en/documents...

Note that the cost of overly onerous regulation (e.g. requiring that every computer manufacturer replace these chips even though the problems can largely be worked around in software) is of course passed onto consumers.

Re: Meltdown Update Kernel doesnt boot

#109

Post by drb91 »

pubby wrote: post #106
drb91 wrote: post #99

Earlier quoted context omitted.

It does if you have something at 0x0. Or, to put it another way, I have no clue to what you're referring--what do references have to do with "The Billion Dollar Mistake"[0]? [0]: https://en.wikipedia.org/wiki/Tony_Hoare#Apologies_and_retra... EDIT: my apologies, that joke was actually pretty good.

What modern systems even map memory to 0x0? Doing so breaks the C standard, among other things.

Again, I am unsure how this relates to "The Billion Dollar Mistake" I linked above and was referring to.

I am not sure your point. The reason modern systems don't map memory to 0x0 is because NULL pointers exist. It is a reflection of a leaky abstraction equating pointers to references. That leaky abstraction has (or so the argument goes) caused >$1B in software bugs.

The other mindset would be "malloc always has to allocate memory or otherwise indicate failure; you cannot cast from a integer to a pointer; you cannot perform arithmetic on a pointer to get a new one; you must demonstrate there are no hanging references when freeing". This is essentially what rust did for safe code.

The reason why I indicate so much skepticism is that rust is the first time I've seen the problem solved well in the same problem space as C. Ada has problems of its own. It's more about how small assumptions can have massive economic (and health, and safety, and ethical) consequences. Certainly comparable to a speculative execution bug leaking memory in an unprotected fashion--in both cases the bugs find their way through human error in evaluating enormously complex systems for incorrect assumptions :)

Re: Meltdown Update Kernel doesnt boot

#110

Post by collinmanderson »

Consultant32452 wrote: post #80
_Nat_ wrote: post #55

Earlier quoted context omitted.

Are you suggesting that we recall the great bulk of modern CPU's? Like, literally gut everyone's computers, including those in data centers and running critical infrastructure, until replacements are eventually manufactured? Or did you mean something else?

Boxed Intel processors carry a 3 year warranty. It certainly seems reasonable for everyone who bought a CPU within the last 3 years to expect a warranty replacement with the manufacturer defect fixed. In the EU virtually every product comes with a 2 year warranty. So every CPU sold in the EU in the last two years should be replaced for free by Intel, even through OEMs. I wonder what potential class action lawsuits In…

Intel would just say it functions exactly as designed. :)

(because it's a design flaw)

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