Skip to content

Tag: linux-kernel

What’s the purpose of `on_rq` field in `task_struct`?

I am now reading the source code of try_to_wake_up() function of Linux Kernel. This function does a lot and includes this: return p->on_rq == TASK_ON_RQ_QUEUED. So, what is the actually purpose of on_rq field in task_struct. BTW, does there exist some manuals or reading materials to introduce all the fields in task_struct? I think a fully understanding of these fields

How to limit privileged user access at Linux Kernel level?

I found this answer on learning Linux Kernel Programming and my question is more specific for the security features of the Linux Kernel. I want to know how to limit privileged users or process’s access rights to other processes and files in contrast to full access of root. Until now I found: user and group for Discretionary Access Control (DAC),

Dynamically find the address at which the kernel is loaded

I’d like to be able to programmatically find out the address at which the linux kernel is loaded. If there are tools out there that already do that, I’d be willing to use them. However, inspecting the PARAMS_PHYS field in the .config during the kernel build is not an option. How could I go about doing this? Answer From where

How to achieve accurate timer in linux kernel

When i write a infrared remote control driver, I have to control delay accurate time during enabling and disabling PWM. At first i used udelay() function in kernel, but i found it’s not accurate at all as i said in another post AFAIK, other timeout functions provided by kernel can’t provide accurate time because of scheduler, when timeout, kernel still

How to add poll function to the kernel module code?

As I know, to inform the user space from kernel space, one way is to using poll. That means kernel driver should provide poll method first. Below code is found from internet, and it really works! I can do like this to make it work: And then to see the result. But how to add poll method to it? I