How to write to protected pages in the Linux kernel?
I am trying to add a syscall in a module. My rationale is: This is for a research project, so the exact implementation does not matter. Adding syscalls in the kernel-core takes a prohibitively long...
View ArticleWhy there are no major page fault on a program that maps a file to memory?
I am trying to demonstrate paging in Linux. I wrote a small program that maps a file to virtual memory with mmap(), waits for input, access the allocated memory, and waits for input again. I check the...
View Articlewhy does arm atomic_[read/write] operations implemented as volatile pointers?
He is example of atomic_read implementation: #define atomic_read(v) (*(volatile int *)&(v)->counter) Also, should we explicitly use memory barriers for atomic operations on arm?
View ArticleAbout linux v5.4 kernel arm64_memblock_init() / fdt_enforce_memory_region()
Q: What is the use of linux,usable-memory-range property? Background: Recently I am analyzing how Linux kernel initializes memory. When I go to arm64_memblock_init function in arch/arm64/mm/init.c, I...
View ArticleMT9T031 sensor driver for I2C bus (soc-camera subsytem and platform data)
I am studying the code of MT9T031 sensor driver: MT9T031 sensor driver It's clear that it uses soc-camera subsytem, and we need to define platform data. The comment says: The platform has to define...
View Articlesome kernel address is not mapped for arm64bit
I run command and found this kernel address is not mapped. Can anyone help me to understand what might be the reason for it? #cat /sys/kernel/debug/kernel_page_tables This address range is not mapped....
View Articleinsmod: ERROR: could not insert module HelloWorld.ko: Operation not permitted
I am trying to learn linux and kernel development. I am able to build the module but am unable to load it. HelloWorld.c /* * hello-1.c - The simplest kernel module. */ #include <linux/module.h>...
View Articlefastest to rebuild the linux kernel using rpmbuild
I just built the linux kernel for CentOS using the instructions that can be found here: https://wiki.centos.org/HowTos/Custom_Kernel Now, I made my changes and I would like to rebuild the kernel and...
View Articlehow to avoid printk log dropping in linux kernel
Is there any tips or method to avoid kernel log drop or log buffer overrun ? I have increased the log buffer size to maximum with below code change. I'm running in high end device only. But, still...
View ArticleHow to remove or uninstall applications in ubuntu using terminal?
In ubuntu iso how to uninstall or remove app from the device using terminal only, so any one send the command for remove application.
View ArticleAbout arm64 early_pgtable_alloc function
Background:kernel version: v4.14.149Show the code first:void __init paging_init(void) { phys_addr_t pgd_phys = early_pgtable_alloc(); /* My first question */ /* pgd_set_fixmap(pgd_phys) maps FIX_PGD...
View ArticleHow do I include a kernel module in rpm-ostree compose server
I would like to include a custom kernel module when composing an rpm-ostree server (based on centos atomic), however this only seems to work if I create an rpm containing the compiled kernel module in...
View ArticleHow to pass parameters to Linux system call?
I'm a college student studying OS.I'm trying to add my own system call in Linux kernel, and something is going wrong.My environment is stated below:Linux Kernel v.4.19.164-bit Ubuntu LTS 18.04.1 with...
View ArticleInstall additional kernel modules
I need pwm-bl.ko kernel module for my Raspberry Pi, but it is not present in my /lib/modules directory. Sure, I can download kernel sources for my kernel version, select necessary modules to build,...
View ArticleApache 2.4.35. - vulnerability "Port Listener Command Injection"
we are running recently we had a vulnerability scan , and the result we got "Port Listener Command Injection". can any one please help to identify the cause for this or any test case to test this...
View ArticleWhat is the syntax for filtering by arg in ftrace raw_syscall events?
I am automating actions of ftrace in a c++ executable and am almost certain I had got this working in the past, but now am constantly having problems with it (possibly due to different behaviour on...
View ArticleParameters of syscall_64.tbl, syscall_32.tbl in linux kernel?
What is the meaning of fields of the line that just add to the system call table Ex: 548 64 hello sys_hello
View ArticleWhere can I find documentation for linux net event in...
I want to use bpf to intercept/inject to some events but I couldn't find documentation for them, like in this://https://github.com/torvalds/linux/blob/master/include/trace/events/net.h#L143...
View ArticleQuestion on Android Dev and Linux. I can not understand the directory...
I found a link to the directory tree of the Android kernel source code: https://github.com/aosp-mirror/platform_system_core?files=1And I had questions about this directory tree. • Is this the Android...
View ArticleHow to add parameters to Linux system call?
I'm a college student studying OS.I'm trying to add my own system call in Linux kernel, and I don't understand exactly how to add these parameters into my code. I want to write only one system call but...
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