Kinda funny, kinda neat.
I have no idea what the QR-code might reveal (I could not read it from this picture), so I pixelised it just to be sure.
FWIW I know exactly what happened and did not panic. To reproduce, boot your device with init=/bin/sh, then type exit.
CachyOS
The picture above is generated by Drm panic which is part of the kernel itself, or maybe a separate module. The data in the QR code is the kmsg log.
Not systemd, which wasn’t running when that happened.
And it’s been around for years; I guess I haven’t had a kernel panic in a long time.
The QR code contains the panic stack trace text, directly encoded into a URL and a parameter. When you scan it, it goes to the website, which takes the parameter, decodes it and displays it as plain text.
Personally, I think it’s a terrible idea compared to just showing the logs, because now you need internet and a phone with a camera to read a kernel panic log.
Edit: yes, it was Systemd who implemented it.
It’s a kernel thing, not systemd
Edit: yes, it was Systemd who implemented it.
Nah, systemd-bsod is different and designed to show info about boot failures:
It’s rather quite useless.
drm_panic on the other hand has nothing to do with systemd, and is what’s shown in OPs post. The link can be quite useful for users to post their issues on bug reports or whatever. But if you know what you’re doing, then it’s pretty easy to configure it to print text instead.
Also remember, the reason drm_panic exists is because graphical outputs would otherwise freeze during a kernel panic, and not show anything useful.
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I disagree. The logs typically do not fit on the screen in text form, especially on low resolutions (like if the system has to fall back on an alternative graphics mode, which tends to happen more frequently in the event of a crash). Granted, a website is not the best possible solution and has the risk of leaking data but at least it is “a” solution. The data is encoded sure, but not in an obfuscated way. If you wanted, you could decode it with other means (for example a dedicated app that scans it).
Thanks for the info, but this is not that.
The picture above is generated by Drm panic which is part of the kernel itself, or maybe a separate module. The data in the QR code is the
kmsglog.Not systemd, which makes sense considering systemd was not running when that happened.
That QR code could be helpful, but why can’t we have both? Show me the backtrace and logs, and stick a code in the corner in case I need the Internet’s help.
The QR stacktrace allows a method of copying the information off the machine, which may now be unable to function any longer.
If this error meant you can no longer boot to retrieve the error it’s goin to take you a lot longer to fix it because you have to now find the problem with no clues.
I get it. It’s more descriptive than an error message, and the few kilobytes you can cram into a QR code is great for that.
It sounded like other people were worried about data exfiltration, or disclosure to a third party. I haven’t had a chance to test this. Where does the QR code go?
So it’s leaking information about your system to an external site?
That’s just what we need.
The theory is that the site just hosts a small JS snippet that locally decodes and shows you your logs.
But yeah, now that you mention it, it would be trivial for the site to get and store the logs, and you wouldn’t even notice.
Oh I see. If the URL puts the sensitive information after the anchor, like
https://example.com/bsod#sensitive-info-goes-herethen the browser would never send that part to the server. Everything after the anchor is just used locally by the browser to scroll the page to a specific place (or in this case for the javascript to read and process).You’d need to check every time you scan a QR code though that the
#is in the URL and it’s not malformed. Trivially replacing the#with a?would turn the private URL into one that sends all the data in theGETrequest. It’s training users to do something risky.Oh and it also assumes that the javascript hasn’t been tampered with to upload the data somewhere.
I don’t like it.
It’s possible to use QR code reader apps that do not automatically go to the WWW.
But who’s going to go to that effort on their slab of glass?
I agree that the whole concept of QR code scanning is problematic.
But who’s going to go to that effort on their slab of glass?
Those who would like to make extra sure their data stays private. On an unrelated note, what kinds of data could be considered confidential in said log?
I use URLChecker on Android as my default browser so I can inspect any kind of link before opening it. It’s the most useful tool I’ve found on mobile.
it’s leaking information
No.
Scanning the QR code (on a different device presumably) might do that though.
It’s kinda what QR codes do.But I agree, it’s not a good idea. Because people will scan that code and let their slabs of glass do their thing.
can that dense code be scanned with a phone? pretty sure mine can’t
That’s what happened to me too, although i tried to scan it later off the image I took.
Okay, great. I don’t have a smartphone. So I cannot see the error log anymore.
The most important info is at the bottom of the screen. I also believe you can turn this feature off if you prefer plain text
let’s submit a patch to display error log as text too on the bluescreen
Hey, I happened to have a handful of smartphones that still have an ok battery and just collect dust in the shelf.
If you want me to ship one to you, pm your address.
Gonna help my linux buddies so that they can scan QR codes if their OS crashes.
(not sarcasm)
I should’ve tried to switch ttys, might have helped.
Switching ttys wouldn’t have done anything. The kernel logs are usually saved to efi_pstore (or sometimes erst) by default though.
Edit: you can also set
drm.panic_screen=kmsgas a kernel parameter to print the logs instead of the QR.
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Did you maybe try to press
Esc?
When it shows the pretty boot logo, you can do that to see the logs, so maybe it works here as well…Nah, when a kernel panic hits then everything’s screwed.
Pressing ESC does work for systemd-bsod (which is different) and as you mentioned Plymouth; but not drm_panic.
My picture looks like that (on one monitor of course) and it most likely wasn’t created by systemd, which wasn’t even running when that happened, but by the drm_panic kernel module. I’ve edited the OP.
Nice dual display setup :)
I never scan, just check the journal for errors from previous boot after restart. Most recent was my pcie low power shenanigans with my onboard WiFi. Simple fix and now its working /no bsod since.
“This just in - running commands that induce a kernel panic causes a kernel panic, we’ll have more at 11.”
The QR code is pretty dense , probably plenty of space to include the panic reason and stack trace.
Edit: For those of you that don’t know, exiting or crashing the init process (PID 1) causes the kernel to panic. Essentially it’s the, “Well what the hell do I do now if I have no processes to serve?” response.
Still, a QR code is a marked improvement on the “Something went wrong :(” message of recent Windows releases.
“This just in - running commands that induce a kernel panic causes a kernel panic, we’ll have more at 11.”
What’s with the snark? I’m just sharing what is funny (to me): that somebody gave a Linux kernel panic this aesthetic, referencing a familiar “feature” of a less loved OS.
On lemmy you’ll allways find the weirdos and elitists that have been pushed out of the mainstream.
The linux equivalent of bsod has been introduced pretty recently, so it’s normal for few people to have experienced it yet.
Also somewhat relevant xkcd: https://xkcd.com/1053/
I get what you mean but this is not fediverse-specific.
I have meanwhile found out that the screen above was not produced by systemd but rather by the drm_panic kernel module. Makes sense since systemd wasn’t running when it happened.
Next time it happens (hopefully not) I’ll try to switch ttys, maybe the logs are still visible, white on black.
It’s a subculture phenomenon, and lemmy linux is a subculture of a subculture, so it’s more intense.
I’ve been a moderator on some linux reddits in the past. And the less users there were in the sub, the more negativity, rudeness, gatekeeping and other toxicity was there. But ofc what I say is just an opinion based on my subjective experience so idk.
The linux kernel bsod is even younger than that, august 2024 iirc.
