Everything about UNIX kernels: development, configuration, compilation, design, etc.

learn more… | top users | synonyms

1
vote
0answers
23 views

Userspace Network Stack

I am writing a (very simple) userland IP network stack. For this purpose, I need to go "around" the OS network stack and obtain the raw Ethernet frames. The tap interface sounds like a way to go, but ...
20
votes
3answers
30k views

How to disable USB autosuspend on kernel 3.7.10 or above?

I've updated my HTPC from kernel 3.7.10 to 3.10.7 and it seems CONFIG_USB_SUSPEND is now gone from the kernel options and included in PM. The main problem I'm facing is that I have an external HDD ...
0
votes
0answers
21 views

dracut-initqueue: Could not boot, /dev/disk/by-uuid does not exist

I've just installed second linux kernel on my machine and after the boot, I'm getting following error: dracut-initqueue: Could not boot [Warning] ...
1
vote
0answers
18 views

How to verify NX usage in Linux kernel?

I'd like to verify that the current system is using NX bit protection somehow. I know that this can be done by checking the initial lines in the dmesg output. But that's a rolling buffer, so I'm not ...
1
vote
0answers
22 views

How to uninstall linux kernel?

I was building linux kernel from git master for ubuntu all day, I was not able to build packages, so I just ran sudo make module_install install. How to remove it? Makefile doesn't provide make ...
3
votes
1answer
8k views

After installing a new Kernel in Ubuntu 14.04, rebooting takes me to busybox initramfs. How do I mount a filesystem after that?

I have a virtual machine with Ubuntu 14.04 in it. I recently built and installed linux-3.14.5 kernel on it, and tried to boot into it, but it drops me to BusyBox v1.21.1 built-in shell. Here's what I ...
0
votes
0answers
3 views

dma_free_coherent doesn't work for a large array - Kernel module [migrated]

I am trying to allocate an array of 0x40000 bytes (256kB) for dma purpose with dma_alloc_coherent in a driver (so in kernel space). I allocate this array inside the probe function and I free it with ...
1
vote
2answers
892 views

How to manually compile Fedora 20 kernel

I am trying to recreate an environment for debugging purposes. I require Fedora 20 specific kernel version (in this case its 3.17.7-200.fc20.x86_64). I have manually compiled vanilla kernel (3.17.7) ...
1
vote
2answers
682 views

Linux Kernel - Wacom Tablet (CTL-490DW-S) - Lockout

I'm a bit of a beginner with Linux and after trying to fix this over the last few days I've finally given up and need your help. I'm trying to use my new Wacom (CTL-490DW-S (Intuos DRAW)) drawing ...
4
votes
2answers
2k views

When will Debian switch to Linux 4.x? ( and support the live kernel patching ? )

Wikipedia says that current Debian 8.2 Jessie is based on kernel 3.16.0, so I was wondering when a native version based on kernel 4.x would be released and if the live kernel patching will be there as ...
2
votes
1answer
62 views

How does a bootloader actually hand off to a kernel?

Assume I have a bootloader with a kernel and initrd line. For all intents and purposes, I now have 2 or 3 stages of "kernel" going on: firmware grub (or other bootloader) actual linux kernel The ...
1
vote
1answer
25 views

Wacom Tablet (integrated; X201T) disconnects sporadically

I have an X201 tablet with stylus and finger multitouch running Ubuntu 14.04.4 with the 4.2.0 kernel. For no apparent reason, it seems to have an affinity for not recognizing finger (henceforth ...
1
vote
0answers
27 views

How to know when I could reactivate HWP (Hardware PStates)

I have a x1 carbon 4gen, and my computer hangs during boot on "HWP enabled" message. For now the solution is to disable HWP (Hardware PStates) with the option intel_pstate=no_hwp on boot. There is a ...
3
votes
2answers
12k views

Partition table not recognized by Linux kernel

I experience relatively often that the partition table of a USB stick or SD card is suddenly no longer recognized by the kernel while (g)parted and fdisk still see it, as do other systems. I can even ...
0
votes
0answers
11 views

Kernel make install error for RTAI 3.8 on CentOS 6.5

Before posting I have read almost every similar post I could find on this and other websites but I haven't found an useful answer. I have to install a custom software that needs RTAI 3.8 on top of ...
0
votes
0answers
48 views

Kconfig (bool/def_bool/tristate)

In a Kconfig file, what are the differences between : bool def_bool tristate Thank you.
2
votes
2answers
40 views

How to get the absolute position (x, y coordinates) of a finger on a touchpad?

Main question: How to get the absolute finger position on the touchpad? I would like to get the absolute position (x, y coordinates) of a finger on a touchpad? I believe it is possible to extract it ...
2
votes
2answers
726 views

Wireless constantly reconnecting on Ideapad running Arch

I just bought a new laptop, a Lenovo IdeaPad U330 touch, and after some struggle (with the Secure Boot stupidity) I have managed to install Arch Linux. I have configured my system, installed all the ...
0
votes
1answer
24 views

is there a description for kernel messages?

I use dmesg to output kernel messages, but since I'm new to linux I have no idea what this informations mean. Is there a good tutorial or description so I can understand the messages. for example: ...
0
votes
0answers
15 views

Mouse button stops working intermittently

I have noticed that I'm not the only one with mouse button problems. This problem seems to affect multiple users on many different Linux versions regardless of Desktop versions (at least in Unity ...
0
votes
1answer
37 views

What step am I missing to get my 2.6 ARM kernel running in QEMU?

I am trying to cross-compile and boot a Linux 2.6 kernel for ARM using QEMU. I have basically followed the same instructions that are included in seemingly every single tutorial on the topic. ...
1
vote
0answers
24 views

How to trace the life cycle of kernel threads by following creation and switching?

How to trace the life cycle of kernel threads by following creation and switching ? kernel_thread() and schedule() are the 2 functions I know that but have no idea how to implement it..
0
votes
2answers
98 views

Why can't I find kernel headers on CentOS 7 when trying to install VirtualBox Guest Additions?

I have a minimal CentOS 7 installation as a VirtualBox 5.0.16 r105871 guest on a Windows 8.1 host. uname -r reports "3.10.0-327.10.1.el7.x86_64". When I try to run VBoxLinuxAdditions.run I get an ...
0
votes
0answers
11 views
0
votes
0answers
9 views

Raspbian Kernel Oops at fs/dcache.c

We have a Raspberry Pi 2 running Raspbian 8 Jessie. We are running a simple Python 3 based Flask server to read from GPIO pins and toggle a relay (Externally powered). This system is polled every ...
0
votes
0answers
18 views

Ubuntu upgrades blocked due to insufficient disk space for linux-image [duplicate]

I am running Ubuntu Server 14.04 LTS on a desktop at my home that I was intending to turn into a server, but I never really did much on it. I then decided to turn it into a send-only SMPT server, but ...
0
votes
0answers
15 views

GMA500 video chip uses mode that monitor can't sync to (even text mode)

I have a new CentOS7 installation which starts fine (I see the Grub2 menu). If I disable RHGB I can even watch bootup to a point - then all video disappears. The OS is booting to runlevel 1 (text ...
0
votes
2answers
107 views

Why can't I run android apps on generic linux? [closed]

I know about projects like archon, and various emulators exist, but it seems strange that I can run windows programs but not android programs under a stock linux kernel.
0
votes
0answers
17 views

Dynamic mdev ifup and ifdown of network interface

Is it possible to have an mdev.conf rule that would run ifup on device creation and ifdown on detach? i.e. eth[0-9] root:root 660 @ifup $MDEV | $ifdown $MDEV
-1
votes
1answer
53 views

How to install kernel 4.4 on debian testing?

Hello can someone tell me how to install kernel 4.4 on current debian testing ? I have a bug that might be solved by the kernel 4.4 so I want to give it a shot but can't find the name of the package ...
1
vote
1answer
629 views

How to troubleshoot high kernel time (high network usage; high interrupts)

I've noticed that I have high kernel time when doing a lot of network traffic in Linux. I also noticed that 45% of my CPU is spent doing interrupts. How can I further troubleshoot this?
3
votes
2answers
38 views

How can I activate extra-verbose mode (debugging mode) during Debian boot?

How do I activate extra verbosity during boot, on Debian? I removed the quiet parameter and tried to add debug but it didn't help. My problem is that my keyboard takes 2-3 min to activate so it ...
3
votes
0answers
92 views

How to interpret perf -e cache-misses:pp?

I find the behavior of perf top -e cache-misses:pp -p <my_pid> quite confusing. I own an Intel i5-3230M, running kernel 4.4.5 64 bit. If I just run that commmand, I get basically no samples ...
0
votes
1answer
68 views

What is the difference between micro-kernel and monolithic-kernel? [duplicate]

I heard that Unix/Linux is a monolithic-kernel whereas Hurd is micro-kernel. So, I want to know what is the difference between these kernel type?
0
votes
0answers
28 views

Kernel panic dump analisys

We got a kernel panic today and I think that one scsi device caused it. Can you help me to interpret this output? What does <<EOE>> mean? <0>Kernel panic - not syncing: Watchdog ...
6
votes
2answers
2k views

How can I check my kernel preemption configuration?

I want to check if my Linux kernel is preemptive or non-preemptive. How can I check this using a command, something such as uname -a?
1
vote
0answers
33 views

Build custom EDID with several modelines

I would like to build custom EDID using kernel sources. But I need to use several modelines - more refresh rates for same resolution. Is it possible using method in kernel sources? Could you please ...
0
votes
1answer
94 views

How to install kernel sources

I 'm running Angstrom distribution (console only) on BeagleBoard-xM. Image was build on Narcissus, with Bootloader Files (x-load/u-boot/scripts) added. I noticed that usr/src directory is empty. I ...
0
votes
0answers
211 views

I installed linux. And it doesn't recognize usb keyboard and mouse

When I boot computer with kernel 2.6, I can use usb keyboard and mouse. But If I use kernel 3.10, It doesn't work. With kernel 2.6 $ lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root ...
8
votes
3answers
13k views

Where to download Linux Kernel source code of a specific version?

Is there a resource to download a specific kernel version source? For example, I want to get 2.6.36.2 sources to compare with this package and see what changes were introduced?
2
votes
1answer
27 views

How to map Linux hard drive identifiers like “sd 3:0:0:0:” to ones like “ata8:”? [duplicate]

In my kernel log, I can see entries like: [ 0.765510] sd 3:0:0:0: [sdb] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) and when something fails, it's usually something like: [ ...
0
votes
1answer
10 views

Add symbols of LKM to kernel

I am trying to get my android kernel working but I have a kernel module that is needed in order to get access to the file system of the device. Unfortunately there is no source code available so there ...
1
vote
2answers
87 views

How to make a minimal bootable linux (only with terminal) from kernel source code? [duplicate]

I want to make a very minimal linux os which only have a terminal interface and basic commands/applications (busybox is my choice for commands/apps). I don't want the installation option on my os. I ...
0
votes
2answers
34 views

CPU: 13 PID: 15452 Comm: ssd_blk/0 Tainted: G B I E 3.19.0+ #1

I developed a module which works as an emulator for a block device. When I write into the block device, I get this in dmesg and the module crashes. I cannot get any hint about what is going on? ...
90
votes
5answers
143k views

How to reload udev rules without reboot?

How should one reload udev rules, so that newly created one can function? I'm running Arch Linux, and I don't have a udevstart command here. Also checked /etc/rc.d, no udev service there.
4
votes
2answers
2k views

dmesg: pci BAR 7: can't assign io

I have VMware virtual machine running Debian Wheezy. I have compiled my own kernel 3.14. I have noticed dmesg is flooded with messages pci BAR 7: can't assign io (size 0x1000). I have no idea what ...
1
vote
2answers
41 views

What 4.2 Kernel Optimizations could I make to speed up CR48 netbook?

I have a CR48, had one for years. Love the little grimlin, but it is still a single core machine with the chances of upgrading the processor being slim and none (Even then what looks to be the best ...
0
votes
1answer
26 views

Loop device support on self compiled kernel doesn't work

I compiled 3.10 kernel, I checked that these configuration lines are not commented CONFIG_BLK_DEV_LOOP=y CONFIG_BLK_DEV_LOOP_MIN_COUNT=8 When i'm trying to mount loop device I get this error # ...
1
vote
0answers
58 views

Error installing kernel from source!

I compiled the latest Linux Kernel (4.5.x) from Linus's git tree. The Kernel compiled perfectly with no errors. After compiling the kernel I installed the modules using sudo make modules_install. That ...
1
vote
1answer
45 views

How to spoof uname -rs per process

My ubuntu server returns Linux 3.13.0-63-generic when I run uname -rs. From what I found in internet, uname is also a system call which can't be easily overridden when third party program run this ...