How to find memory allocated by a kernel level process in linux?
I have written a simple kernel module to remove all the vowels from a given string. I want to find out about how much memory is allocated by the process, number of page swaps and number of context...
View ArticleHow can I get an exclusive access to files from linux kernel?
I'm searching for a way to prohibit an access to some files from kernel mode. Honestly, I'm not quite familiar with linux. If I needed to do this in Windows, there would be no problems: for instance, I...
View ArticleCapturing USB packets of a specific device
I have multiple USB devices on a single USB bus in an embedded system running with Linux, I want to capture USB packets of a specific device. I got the device number using lsusb command.Is it possible...
View ArticleCannot use set_memory_rw in Linux kernel on ARM64
I am trying to develop a kernel module that hooks the read() system call. for some reason the set_memory_rw() function does not seem to work.I saw another question of this sort but I didn't really...
View ArticleWhy is my kernel resetting my machine immediately?
I am building a custom kernel using Buildroot 2020.02.1 for a PC mounting a AMD GX-222GC SOC.The default external toolchain is amd-2016.11-19 from CodeBench. Kernel built with that toolchain boots...
View ArticleTrace mount(2) and unmount(2) callers on the system
I am trying to debug an issue where an NFS share is auto-unmounted.I am suspecting systemd is the one which is doing a lazy umount but needs to be sure.Is there a way to know which process called...
View ArticleDebugging kernel panic error
I have a arm board on which I am running yocto with kernel 4.1.15. While I am running my python program I get following kernel error frequently but randomlyUnable to handle kernel paging request at...
View ArticleIn which module is aplay and arecord compiled in Automotive Grade Linux (AGL)?
I'm trying to understand the AGL build procedure. I have to modify the AGL build so that it uses my version of aplay.c and generates an aplay binary that's based on my version of aplay.c instead of the...
View ArticleHow to enable dump_stack() in linux kernel?
I am trying to build a new syscall that calls dump_stack(). How do I enable dump_stack() in the first place? Which config files and macros do i have to change?
View ArticleInterrupt handler: request_irq returns error code -16
I am writing a simple driver, which could register an interrupt and handle it.I am using the request_irq function but it returns this error: genirq: Flags mismatch irq 29. 00004004 (irq-test) vs....
View ArticleDoes usermodehelper_exec bash command support background completion '&'?
Im am familar with:int call_usermodehelper_exec ( struct subprocess_info * sub_info,int wait);retval = call_usermodehelper(argv[0], argv, env->envp, UMH_NO_WAIT);and can successfully pass in a shell...
View Articlehow or which file to modify in the CPUID emulation code in KVM to report back...
Is this the correct linux kernel code to modify - how can i make the change to emulate CPUID code and which function i need to change. thank you#include <linux/kvm_host.h>#include...
View ArticleAdaptation from old init_timer to new timer_setup
I have been trying to port a driver from 2.6 to 4.n without support from the original board manufacturer (and very limited Linux experience). The original driver uses init_timer() and passes in a...
View Articleheap_end_ptr in Linux kernel setup
In newer Linux kernel arch/x86/boot/header.S file, I don't understand the use of heap_end_ptr near start_of_setup. It is supposed to point to the end of usable heap minus 0x200. The logic seems to load...
View Articleioremap returns NULL
I'm trying to create a customised UART driver for Raspberry PI.I try to ioremap the MMIO. But ioremap returns always NULL.#define UART_REG_BASE_ADDR 0x7E20100pUart = ioremap(UART_REG_BASE_ADDR,...
View ArticleHow to check migration ability is disabled for some physical address?
I need to code function to check that page migration is disabled:int is_page_migration_enabled(unsigned long paddr); /* physical address is input */Is there some Linux API to do this?UPD:And is there...
View ArticleHow does the Linux kernel temporarily disable x86 SMAP in copy_from_user?
I want to know how the Linux kernel disables x86 SMAP when executing the copy_from_user() function. I tried to find something in source code, but I failed.Supervisor Mode Access Prevention (SMAP) is a...
View ArticleSymlink inside sysfs
I trying to adapt 4.9 msm8953 kernel [1] for my phone - Xiaomi Redmi Note 4x. It was originally shipped with kernel 3.18.Kernel almost done, however one of the last problems is changed sysfs structure...
View ArticleHow to write some test cases to validate SPI driver working in linux
I Want to write few test cases related to SPI driver validation in linux. So if anyone is having any idea regarding it please suggest me. Or give some example so that I can start writing test cases.How...
View Articledevice tree gpios on Linux kernel for AGX jetson-Xavier
I am using a Xavier AGX, and I found the following output on my dmesg while booting up:[ 0.963531] mc-err: mcerr ops are set to t19x[ 0.971308] iommu: Adding device 2600000.dma to group 57[ 0.978632]...
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