I updated today (05.01.2019) and it failed horribly.
Before update, I went into tty(ctrl+alt+F2) because of issues from past when updating with GUI on, and there did "sudo pacman -Syu"
Update was taking a long time, so I left my laptop updating and went away for maybe 20-30 minutes. When I came back, whole screen was filled with some kind of errors I think or something.
The lines I can remember are:
Somewhere at the top was: Watchdog: Bug: soft lockup - CPU#5 stuck for 22s!
At few lines were info about my hardware, like what is my CPU, GPU, etc...
Then many lines I could not understand at all, like: "Process: fdsagfdbsfd" (yeah, it did not have name or anything, just letters, maybe even numbers"
Last line was something similar to this: "Code: 7a 67 e1 b2 r9" (it seems to me like some hex code, it was quite long, these numbers and letter I wrote are made up, dont remember exact thing)
That is all I remember from that screen, even though there was more than maybe 30 lines of something, unfortunately I did not took a picture of it
And the bottom was cursor waiting for something, and then every few seconds (maybe every 30s) whole screen flickered(dont know right word in english, it was like when you open terminal, do system update, and many things are happening, it is so fast you can not read it. But this was like all lines I saw were immidietely removed at one and new ones shown immidietely, not like normal update where you can see new lines coming from bottom to top) with same lines.
I waited for a few minutes, but nothing changed so I shutted down my laptop with power key. Then I started my laptop, chose Manjaro (I dual-boot Manjaro and W10) and only two lines:
error: Invalid magic number
error: You need to load kernel first
I googled those problems, but it seems that people had such a problem only while installing their OS, not when it was already installed. What can I do now? The most important thing is to not loose data I had on disk. But preferably I do not want to reinstall my Linux again because of all the struggle I had while installing it first time(because dual boot, because millions of problems I encountered bcs I have Nvidia + intel gpu, because installing all IDEs and other big apps).