Skip to content
Advertisement

Tag: linux-kernel

Computing the set of writes when executing a function

I want to write a function computeWriteSet that takes an arbitrary function f as an argument and (1) executes the function f and (2) returns the set of places modified or written to (addresses/pages/objects) during f’s execution. What options exist for implementing it? What are their tradeoffs (in which case which implementation is more efficient and what are the limitations?)

Adaptation from old init_timer to new timer_setup

I have been trying to port a driver from 2.6 to 4.X without support from the original board manufacturer (and very limited Linux experience). The original driver uses init_timer() and passes in a pointer to the timer_list structure. That timer_list structure’s data element was set to a pointer to another memory structure and the function element set to the callback.

Kernel Panic with Buildroot Linux

I (try to) make a complete minimal Kodi Linux system with buildroot from scratch, everything compiles fine and i also got it to boot but after some lines of console output and graphics reset it gives me a kernel panic error: I have no clue why… My buildroot config file: https://pastebin.com/7PC4zLEa Image from the kernel panic: https://imgur.com/a/dPECTRH Answer It turns

Can I block a new process execution using Kprobe?

Kprobe has a pre-handler function vaguely documented as followed: I was wondering if one can use this function (or any other Kprobe feature) to prevent a process from being executed forked. Answer As documented in the kernel documentation, you can change the execution path by changing the appropriate register (e.g., IP register in x86): So you might be able

How atomic the fork() syscall actually is?

Assuming check_if_pid_exists(pid) returns true when a process with such a pid exists (but possibly hasn’t been running yet) or false when there is no process with such pid, is there any chance in parent code for a race condition when the fork() returned the child pid, however the kernel hasn’t had a chance to initialize the data structures so that

Cannot get memory allocated from `flex_array_alloc` when requesting a relatively big size in linux kernel

I’m doing some linux kernel development. And I’m going to allocate some memory space with something like: ptr = flex_array_alloc(size=136B, num=1<<16, GFP_KERNEL) And ptr turns out to be NULL every time I try. What’s more, when I change the size to 20B or num to 256，there’s nothing wrong and the memory can be obtained. So I want to know if

My newly compiled kernel loses Networking in qemu

I compiled a kernel from source : make defconfig make kvmconfig make -j 4 After this , i use the resulting bzImage for my qemu command: qemu-system-x86_64 -hda debian.img -kernel bzImage -append “root=/dev/sda console=ttyS0” -nographic -m 4096 -smp 2 –enable-kvm -net user,hostfwd=tcp::10021-:22 -net nic It mounts, and I get a shell and everything, but it loses connectivity. In qemu, it

Timing/Clocks in the Linux Kernel

I am writing a device driver and want to benchmark a few pieces of code to get a feel for where I could be experiencing some bottlenecks. As a result, I want to time a few segments of code. In userspace, I’m used to using clock_gettime() with CLOCK_MONOTONIC. Looking at the kernel sources (note that I am running kernel 4.4,

Advertisement