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Microsoft disables Spectre mitigations as Intel’s patches cause instability

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Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#131

Post by josteink »

thanksgiving wrote: post #29
tjoff wrote: post #18

I lost many hours over this last week. The system was unable to boot and finally a thread on reddit came to the rescue ( https://www.reddit.com/r/techsupport/comments/7sbihd/howto_f... ). This actually made the system boot but there are some leftovers being installed on first boot that I've been unable to disable that also causes the system to be unable to boot. So now, the machine is running but as soon as it is res…

Speaking of which, why do so many things require reboot to update on Windows?

> Speaking of which, why do so many things require reboot to update on Windows?

Can't speak for everyone else, but Windows fully supports shared file-access which prevents the kind of file-locks which causes reboot requirements.

The problem is that the default file-share permissions in the common Windows APIs (unless you want to get verbose in your code) is that the opening process demands exclusive access and locking to the underlying file for the lifetime of that file-handle.

So unless the programmer takes the time to research that 1. these file-share permissions exists, 2. which permissions are appropriate for the use-cases they have in their code, and 3. how to apply these more lenient permissions in their code...

Unless all that, you get Windows programs which creates exclusive file-locks, which again causes reboot-requirements upon upgrades. Not surprising really.

In Linux/UNIX, the default seems to be the other way around: Full-sharing, unless locked down, and people seem prepared to write defensive code to lock-down only upon need, or have code prepare for worst-case scenarios.

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#132

Post by quiq »

ohiovr wrote: post #83

My brother was hit by a recent update to Windows 7 that prevented the machine from booting. He went to Microcenter to buy a hard drive. There were a lot of people doing the same thing for the same reason when he was there.

I don't use the windows side of my machine very often, but decided to update it last night. Booted fine (OS on SSD), but one of the HDDs with all of the windows files was corrupted. No go with ntfsfix, chkdsk, partition table destroyed. Reformatted it as ext4 and windows doesn't get to touch it anymore. Haven't tested it too much yet but seems to be working fine.

Remember to use backups!

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#133

Post by Valmar »

cesarb wrote: post #61

In a related development, there are proposed patches to the Linux kernel (not yet merged) to blacklist the broken microcode updates: https://www.spinics.net/lists/kernel/msg2707159.html That patch disables the use by the kernel of the new IBPB/IBRS features provided by the updated microcode, when it's of a "known bad" revision. Since Linux prefers the "retpoline" mitigation instead of IBRS, and AFAIK so far the upstr…

> In a related development, there are proposed patches to the Linux kernel (not yet merged) to blacklist the broken microcode updates

Linus probably won't pull it until it's truly known to be stable, because of his attitude towards having decent quality code and not causing needless system instability.

Without Linus... who knows what would have happened by now.

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#134

Post by mehrdadn »

rlpb wrote: post #121
mehrdadn wrote: post #113

Earlier quoted context omitted.

Development release? Currently I'm on 16.04, and I've never been on a development release of anything on Ubuntu. I'm just describing the behavior I usually see in practice (which it seems someone attributed to "D-BUS" [1]). Obviously the logon session doesn't get messed up if all I'm updating is something irrelevant like Firefox, but if I update stuff that would actually affect system components then there's a good c…

All I can say is that, based on everything I know, that's not the current experience of the majority of users, so it doesn't seem fair for you to generalize this to some architectural problem. I don't know if you unknowingly have some edge case setup or what.

Are you reading the same comments I'm writing? I was literally point-by-point saying the opposite of what you seem to have read me writing:

> You: All I can say is that, based on everything I know, that's not the current experience of the majority of users

>> Me: Yet from everyone's comments here I'm guessing I must be the only one who encounters this.

???

> You: It doesn't seem fair for you to generalize this to some architectural problem.

>> Me: I don't get why it happens in every instance, and there might be lots of different reasons in different instances. IPC mismatch is my best guess for a significant fraction of the incidents.

???

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#135

Post by sundarurfriend »

numbsafari wrote: post #81
mrmondo wrote: post #71

Earlier quoted context omitted.

FYI - The “dude” from Amazon worked for Intel for 8 years before joining Amazon UK just over a year ago.

The “dude” is also probably working under an insane amount of pressure and being made to feel like he is somehow responsible or at fault for the whole situation. Best not to make it personal from the peanut gallery.

> Best not to make it personal from the peanut gallery.

That's a very uncharitable interpretation of your parent comment, which was simply pointing out his connection and history with Intel.

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#136

Post by quietbritishjim »

beagle3 wrote: post #32
thanksgiving wrote: post #29

Earlier quoted context omitted.

Speaking of which, why do so many things require reboot to update on Windows?

There is a very fundamental difference between how Unix and Windows view open files: On Windows, once the file is open, it is that filename that is open; You can't rename or delete it; Therefore, if you want to replace a DLL (or any other file) that is in use, you have to kill any program that uses it before you can do that; And if it's a fundamental library everything uses (USER32.DLL COMCTL.DLL etc), the only effec…

This doesn't fully explain why a reboot is not required on Linux. If a *nix operating system updates sysfile1.so and sysfile2.so in the way you describe, then there will be some time where the filename sysfile1.so refers to the new version of that file while sysfile2.so refers to the old version. A program that is started in this brief window will get mixed versions of these libraries. It is unlikely that all combinations of versions of libraries have been tested together, so you could end up running with untested and possibly incompatible versions of libraries.

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#138

Post by ageofwant »

mosselman wrote: post #112

So what can I do for my next self-built pc? Get some AMD equipment, or is that not enough?

I'll be getting a few high-end Intel CPU's that will soon flood the market on the cheap for home machines running arch.

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#139

Post by mehrdadn »

beagle3 wrote: post #122
mehrdadn wrote: post #113

Earlier quoted context omitted.

Development release? Currently I'm on 16.04, and I've never been on a development release of anything on Ubuntu. I'm just describing the behavior I usually see in practice (which it seems someone attributed to "D-BUS" [1]). Obviously the logon session doesn't get messed up if all I'm updating is something irrelevant like Firefox, but if I update stuff that would actually affect system components then there's a good c…

I have been running Ubuntu since 2004, and except for Firefox which tends to destabilize on update, I’ve observed this twice in 14 years; I update weekly or more often, and reboot every few months (usually on a kernel update I want to take hold)

Maybe it's because you update often so there are fewer changes in between? I update far less frequently.. it's not my primary OS so it's not like I'm even on it every day (or week). I use it whenever I need to.

Re: Microsoft disables Spectre mitigations as Intel’s patches cause instability

#140

Post by Aissen »

vetinari wrote: post #67
thanksgiving wrote: post #29

Earlier quoted context omitted.

Speaking of which, why do so many things require reboot to update on Windows?

> Speaking of which, why do so many things require reboot to update on Windows? We are getting there on Linux too - with atomic or image based updates of the underlying system. On servers you will (or already) have A/B partitions (or ostrees), on mobiles and IoT too, some desktops (looking at Fedora) also prefer reboot-update-reboot cycle, to prevent things like killing X while doing your update and leaving your mach…

It's a miracle that reboot-less updates mostly work in Linux. You need to restart services, etc. to make sure they have the latest libs. Gnome3+systemd does that now:

https://blogs.gnome.org/hughsie/2012/06/04/offline-os-update...

https://www.freedesktop.org/wiki/Software/systemd/SystemUpda...

https://fedoraproject.org/wiki/Features/OfflineSystemUpdates

It's still much faster than a Windows update (at least on my SSD system).

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