Recently I have installed Ubuntu 12.04 LTS ISO image in my desktop. Below is the output of the kernel version I have installed:
# uname -r
3.5.0-41-generic
I am trying to develop a VFS and want the kernel source code version '3.5.0-41-generic' for reference purpose - where can I find the same?
What are the excellent kernel debugging options looking at logs and mapping them to kernel code?
How and which debugger I can use to debug a live kernel flow execution?
Are there ways I can add more printk methods and re-modify the modules? Say I want to know how a FS mount method works - I can modify the required FS code (adding more printk functions) re-compile and reload the modules. Now with aid of my new printk functions I can understand the flow
Why don't you install vanilla 3.5 kernel and try to develop on it?
As a kernel debugger you can use kGDB or just printk.
But... I suggest you to test your vfs on linux running on qemu. Qemu is able to debug the running linux - so you can connect gdb to it and debug the whole emulating system.
Related
I want to customize an image I created for an ARM device (Odroid C1+). Especially I want to checkout some git repositories and install their dependencies.
But when installing go libraries, this bug is happening: https://github.com/golang/go/issues/13024
Is there a workaround? Or do you know another user emulator (or similar) to do this?
A workaround would be to use full system emulation in QEMU - just find an ARM kernel that boots in qemu-system-arm and instead of chrooting into the file system from the host, do it from within QEMU.
I'm setting up the BlueZ protocol stack on a custom system using linux 3.3. I'm using buildroot to setup the filesystem, and specifically am using BlueZ-4.101.
I'm attempting to use the hcidump utility to get some logs, but the binary has not been installed.
I've checked that:
Device driver is installed in kernel
BlueZ Utils is enabled in buildroot .config file
Other utilities work, such as hcitool or hciconfig
Going into the Makefile in output/build/bluez_utils-4.101 it would appear that the object file hcidump.o is being compiled into a binary called btmon.
Further investigation would reveal that in Makefile, btmonis assigned to am__EXEEXT_10, and that is then assigned to the variable noinst_PROGRAMS.
So this is where I'm at. I'm pretty sure that this is an automatically generated Makefile by buildroot. I'm not sure how these files are generated, thus I'm unsure as to why btmon is being assigned to the noinst_PROGRAMS variable.
In summary, I believe that my version of BlueZ uses a binary btmon instead of hcidump. btmon is compiled (binary seen at output/build/bluez_utils-4.101/monitor/btmon), but not being installed onto my target system because of instructions in Makefile.
My best guess would something weird about compatibility between my kernel version and bluez. Any suggestions would be greatly appreciated!
In BlueZ 4, hcidump was distributed as a separate package, bluez-hcidump. This has never been packaged in buildroot, however. So either create your own package for bluez-hcidump, or switch to BlueZ 5. BleuZ 5 is provided by buildroot starting from 2014.08.
I am running into a issue with RH7 kernels. We are running RH6/Centos6 based systems - we normally compile the kernel module once (Centos6.6) and we could install the kernel module on another Centos kernel in the same series (say Centos6.4).
With Centos7 (3.10 kernel) I cannot build the kernel module with says 3.10.0-329 (Centos7.2) kernel and install on a kernel version 3.10.0-227 (Centos7.1) - insmod returns invalid format.
Anyone run into similar issues - are there any workarounds.
Thanks
--
Jimmy
Probably, you want a binary blob - ready-made object file which is part of the module. Look into kernel documentation for know how to build module which uses binary blobs. – Tsyvarev
I am working on linux on ubuntu. I am modifying the source code of linux 2.6.25 by adding a system call while my operating system has some other version of linux installed. To test my modified code, do I need to install an emulator or can I test it on the terminal window itself?
If I can build and compile my linux 2.6.25 on the terminal, how should I do it?
You can test your modified kernel by installing that kernel in your current Ubuntu system.
Please follow following steps to install kernel in your system.
1) compile your modified linux kernel
make
2) Install that kernel using following command
make modules_install install
3) update initramfs as per the changes made in kernel using following command
update-initramfs -u -k 3.0.0
4) Finally, Update the grub loader to add the entry of your kernel in boot loader using following command.
update-grub
5) Reboot the system and execute the uname -r command to verify that you have updated your kernel or not.
reboot
uname -r
You can find your updated kernel with your existing kernel on next reboot and check your updated kernel which you have modified with that kernel.
Please let me know if you need any more information,
You can use User Mode Linux.
Using UML, you can even use gdb to debug it.
http://user-mode-linux.sourceforge.net/
http://user-mode-linux.sourceforge.net/hacking.html
Although the document is rather old, it still works in recent kernel.
in kernel module programming how we can debug using Kdb? I tried with ubuntu 11.04 but I am not getting correct kdb patch for 2.6.38 kernel version so can any one suggest how to proceed
with kdb debugging under this kernel version?
KDB must be turned on in your kernel. I suspect it is compiled off on Ubuntu default release.
Here the details. I expecting you know how to rebuild kernel.