Linux kernel Bug Fixing Spring Unpaid 2024 - Guidance to solve the given Tasks

picoteando

@abhinavjain did you increase the crashkernel size in the GRUB config file? The following values are overkill to make sure there is no bottleneck here:

$ cat /etc/default/grub.d/kdump-tools.cfg 
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=1024M-:1024M"

If you did not, please edit the file and then run update-grub.

If you did indeed increase the crashkernel size there, I would recommend you to narrow down the possible sources of your issue: start with a much smaller image, and make sure that in that case everything works. If it does, your suspicion might be right. Otherwise, you might have a different problem. Try first the original kernel that came with the distro, and then with your custom version.

abhinavjain

Yes, my GRUB config file looks like this presently:

abhinav@dev0:~$ cat /etc/default/grub.d/kdump-tools.cfg 
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=1G,high crashkernel=600M,low nmi_watchdog=1"

I will continue to narrow down the source as per your suggestion starting with the base distro kernel and then the custom one - thank you @picoteando

picoteando

You are welcome, @abhinavjain. I will stress bottom-up approaches throughout the mentorship, because I can tell how time consuming top-down approaches are

Assuming that the default kernel will work (it will, eventually ), I would recommend you to use the distro's .config file to build the kernel to increase the chances of having the right behavior. You can build up with your custom configurations and hit the point where the issue arises again.

I would also keep the crashkernel size pretty high until you get that out of the equation.

mikernl

Sorry I did something wrong and I lost the Discord channel that Javier shared with us, does anyone have the link?
Thanks!

picoteando

@mikernl said:
Sorry I did something wrong and I lost the Discord channel that Javier shared with us, does anyone have the link?
Thanks!

@mikernl PM

ShuahKhanLF

These tasks are to evaluate required skills and should not be discussed.

shibuk

What are suppose to upload in documnetation task? There is lot of files and folder generated when we build documentation.

ShuahKhanLF

You don't have to update the document. You can mention if you are able to build and test the created document.

ashborn3

my tasks are going smoothly but I have a doubt regarding sending patchs.
Say, I need to send the patch for the hello world module,
1. how do I go about it?
2. do I init a git repo and then generate a patch after committing the code?
3. do I have follow all the rules as if I was sending the patch to the mailing list?
4. Also, is it necessary to send the patch using git send-email or can we manually write the mail using a client of our choice?

hrideshmg

I'm quite confused on the panic kernel task, I've managed to write a patch for a module which causes a kernel panic but how am i supposed to access the dmesg output or see the panic message when the system is frozen? I found a few threads which told me to setup kdump and analyze the memory dump but I don't believe that would get me a dmesg log, am i missing something?

cvam0000

@hrideshmg use kdump and set to capture dmesg on every panic or reboot , it worked for me

hrideshmg

@cvam0000 Thanks for the heads up, will look into kdump. Also sorry if this is considered as discussing the tasks, this was the only task i was truly stumped on.

cvam0000

@hrideshmg I spent quite a long time to get the output dump and the process was very informative.

vyshaj

@hrideshmg, You could try using pstore as well. Do a bit of research on it. I personally had problems setting up kdump on my VM for some reason, but worked like a charm on my actual device. It is just a hint, that you can try using pstore too to dump the message.

vyshaj

@ashborn3 As much as LFD-103 suggests, it is the best practice to set up git send-email. So for patch related tasks, I would suggest you do the same. That will get you used to the feature as well.

I am not sure about your third question. Maybe few rules might be relaxed considering the fact that we are beginners(Correct me if I am wrong). But try to follow the course as much as possible. That has the biggest hints and clues.

ashborn3

@vyshaj thank you for your response.
I have completed all the tasks, but the it still shows application pending. What should I do next?