Kernel Panic and Bad page state in process swapper error

Question

A few days ago Ubuntu froze and I hard reboot the laptop and when I wanted to boot Ubuntu again this message showed up.

After searching a lot on the internet, I tried to boot with older kernels and also I booted Ubuntu with different grub parameters (like nomodeset), and every time I faced different kernel panic errors as you can see (and sometimes "Fixing recursive fault but a reboot is needed"):

So I booted ubuntu via recovery mode and I saw weird behavior on the screen. By the way, I was able to enter the root shell prompt and I saw my files too. I Also copied my necessary files to a USB. But the root shell prompt was unstable and after 1 or 2 minutes same errors appeared on the screen I was no longer able to work with it and the only solution was rebooting.

After all of these, I booted from a Ubuntu bootable live USB for any chance of backing up my data and when the disk's process was completed, it was just a blank screen.

I use Ubuntu 20.04 LTS.In the grub menu there are 2 possible kernels:
5.11.0.40-generic
5.11.0.38-generic

My laptop is Acer Aspire F5-573G-793D CPU: Intel Core i7-7500U 2.7Ghz RAM: 8 GB DDR4 and Nvidia GeForce 940 MX with 4GB dedicated VRAM

1. Is my RAM damaged or generally is there any hardware issue?
   
2. How can I back up my data?

Answer 1

Seems to me like a problem with your level 2 cache.

And for what I see 70 Celsius just running a mem test is pretty high. Does it get enough air. At what temps did it run before? If it has to do some real work the temps will go up.

Can you disable level 2 cache in your BIOS/UEFI?

Can you put another processor in your laptop ( have 1 laying around or can you borrow one )? If so try the other processor ( clean laptop/airholes/cooler before booting up ). See if you have the same problems after that.

Can you try this processor in another system? Run the same test. If the result is the same your level 2 cache is broken.

Answer 2

My problem was definitely a hardware issue. And this is how I realized:
After searching on the internet and seeing the signs of this problem (Like freezing the screen or special kernel panic errors), I thought that the problem could be from RAM. I found a program called memtest86 which can do some tests on RAM.
So from here, I downloaded the .iso file and created a bootable image of memtest86 on a USB, I did the tests on my RAM(See usage here) and as you can see, it was able to find more than 10k errors.

So I replaced my RAM with a new one and now everything is working fine.