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

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nl80211 not found

Environment Linux 3.0.8 compiled for ARM FriendlyARM mini210s I cross-compiled iw for an ARM board (friendlyARM mini210s), when I installed the utility and ran it, I got this message: # iw --help ...
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Investigating Active MemInfo

I am seeing high Active usage when I do a cat /proc/meminfo : MemTotal: 65965328 kB MemFree: 51640992 kB Buffers: 1050332 kB Cached: 8516112 kB SwapCached: 0 kB Active: 11512732 kB Inactive: 1878028 ...
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321 views

What is MCH_SSKPD warning in dmesg?

While i was reading dmesg log just to check that everything is fine, i met [ 18.956187] [drm] Wrong MCH_SSKPD value: 0x16040307 [ 18.956190] [drm] This can cause pipe underruns and display ...
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How to properly build a minimal FreeBSD kernel?

Is there any proper way to build a minimal kernel for FreeBSD? The FreeBSD Handbook has the lack of information about this. By default /boot/kernel directory has the pretty big size - around 450MB. I ...
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Is it neccessary for me to update my kernel? And how? [closed]

I'm trying to install Kubuntu on a VM in order to do some deep learning following this guide: https://github.com/BVLC/caffe/wiki/Ubuntu-14.04-VirtualBox-VM I'm stuck in the step of the guide that ...
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No brightness control for opensuse 13.2?

I have posted on brightness issue Here!! After upgrade to KDE 5 Now i cannot change brightness through controls !! AND ALL FUNCTION KEYS (wireless,brightness,touchpad,sound +/-) are not working ...
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Command to install linux headers fails

I need to install my linux headers for an Nvidia driver install. But I get an error when doing so: peter@peter-deb:~$ sudo apt-get install linux-headers-$(uname -r) Reading package lists... Done ...
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Syslog message “rt_bind_peer(0) @ffffffffa0283f57”, twice in every second

My /var/log/syslog on a Debian server is flooded with lines similar to: Dec 23 16:05:40 server1 kernel: [ 686.957585] rt_bind_peer(0) @ffffffffa0283f57 These messages occur up to twice a second ...
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disable transparent hugepages

We are installing SAP HANA in a RAID machine. As part of the installation step, it is mentioned that, To disable the usage of transparent hugepages set the kernel settings at runtime with echo ...
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Does iptables protect from kernel vulnerabilities? [closed]

I read a lot of kernel vulnerabilities which are beyond my understanding. I would like to reduce the risk of an issue related to one. If I block everything other than SSH on a server, will this help ...
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Is the kernel version fixed within the life of a release/version of each Linux distribution?

I read the Table of versions of List of Ubuntu releases. I found that the kernel version for each release is fixed. E.g. the kernel is 2.6.24 for Ubuntu 8.04, 2.6.32 for 10.04, 3.2+ for 12.04, and ...
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Why is userspace slower than the kernel?

I've heard that FUSE-based filesystems are notoriously slow because they are implemented in a userspace program. What is it about userspace that is slower than the kernel?
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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 ...
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what's the difference between page cache and buffer cache?

In linux OS, you can type command "echo 3 > /proc/sys/vm/drop_cache" to release memory, and you can type command "sync" to release the memory. And in linux kernel there are two kind of cache, one is ...
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Custom Kernel to Disable SATA and USB Devices

I am setting up diskless clients that will run on an internal network. I have disabled SATA and USB ports using a BIOS locked with a password, but this is easy to get around by using the jumper to ...
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Is system call the only way that a user program can intentionally affect the state of a Linux kernel?

I think there are several ways that a user program can intentionally affect the state of a Linux kernel. By invoking a system call; By invoking mmap() and writing the memory that has been mapped to ...
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When building a new kernel in OpenBSD 5.6, can the name of `config` be something else?

I am using the release version of OpenBSD 5.6 and have to apply a patch called 004_kernexec.patch.sig (URL: http://ftp.openbsd.org/pub/OpenBSD/patches/5.6/common/004_kernexec.patch.sig ) An excerpt ...
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Some basic questions about Linux kernel's security [closed]

I don't know much about Linux kernel, and I have some questions. What is the main purpose of separating kernel memory from user-space memory? To make sure that a user application cannot do anything ...
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234 views

iwlwifi: timeout delays firmware to be loaded

I'm using OpenSuSE 13.2 beta (which runs by the way very nicely). When starting up, my wireless adapter (Intel Centrino Ultimate-N 6300 AGN/Thinkpad T420) delays about one minute... But then it works ...
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different ways how Linux TCP/IP stack terminates connection

I have a Linux machine which connects to SSH server with SSH client(OpenSSH_4.1p1). SSH client machine has IP address 10.10.11.1 and SSH server has IP address 10.10.10.1. SSH client has kernel version ...
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How does the Linux kernel handle shared IRQs?

According to what I've read so far, "when the kernel receives an interrupt, all the registered handlers are invoked." I understand that the registered handlers for each IRQ can be viewed via ...
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take the DRAM performance of the processes into consideration when scheduling

The CFS scheduler in Linux schedules the processes based on the virtual runtime of CPU. But, the DRAM memory is the bottleneck in most of the emerging domains. Why not take the DRAM performance of ...
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swap partition and its laws

I remember for choice of swap partition, we should use (swap > 2xRAM) at least.Of course it deprecated , because max of computer's ram is very high. kernel support it. My question: i remember each ...
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Disallow change of init kernel parameter

is there any way to disallow changing init parameter on boot time? I want to prevent situation when someone reboot my server, edit grub entry and get access without password. Maybe some kernel ...
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get kernel source code

I need a specific kernel version to compile it with some additional modules. When I typing: uname -r I get 3.8.0-29-generic I need this one. uname -a Linux "..." 3.8.0-29-generic ...
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does the second kernel need kexec enabled

It's clear that you need the kexec syscalls in the 'first' kernel. But does the kernel that should get loaded (with kexec_load and reboot) need to be compiled with kexec? If yes, what extra code ...
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linux vlan bridge feature backport to 2.6 kernels

The VLAN-aware bridge was introduced to the Linux mainline on the 3.x kernels, according to this article on lwn: VLAN filtering/VLAN aware bridge Has this feature been backported to the 2.x kernels ...
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3.10.17 Kernel i2c buses missing on embeded system

On my ARM embeded system I have 4 i2c buses and only one shows up in /dev and in /sys/device/... folders. Other 3 i2c buses are not loaded. There is also no warning message inside dmesg, but there is ...
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Kernel headers for VMware tools

I tried to compile VMware tools on my server. I compiled the kernel myself, I didn't use RPM. As VMware tools needs the kernel header files, I executed the following command in my kernel folder ...
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658 views

BUG: scheduling while atomic

I have just installed Linux (OpenSUSE), and when start the OS, I get an error BUG: scheduling while atomic: systemd_udevd plymounthd... what does it mean?
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ifup wlan0 causes kernel Oops

on my laptop, when I do ifup wlan0, sometimes I get following call trace in dmesg. Other times, the log looks perfectly normal, and there are no kernel Oops messages. In both cases (with errors and ...
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Suspend Crash in android 4.4

During suspend clocks are not turning off, meanwhile when we resume clocks are not getting turning on. I am getting crash like <4>[ 216.945252] WARNING: at ...
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What does LTR kernel mean?

I was reading some sites and came across (LTR) by the number of kernel. Can somebody explain what is means?
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Cannot boot latest kernel update after installing on new system

I recently built my own computer, and I was excited to finally get to the installation of the operating system. I chose Fedora 20 to use as my primary operating system, and I was able to successfully ...
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Who's consuming my inotify resources?

After a recent upgrade to Fedora 15, I'm finding that a number of tools are failing with errors along the lines of: tail: inotify resources exhausted tail: inotify cannot be used, reverting to ...
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Is hardware helping reducing crashes of OS X? [closed]

I am taking an OS course this semester, and we mentioned that device drivers can cause about 85% of crashes(for Windows). My understanding is that: since many personal computers are configured with a ...
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640 views

cc1: warnings being treated as errors when compile FreeBSD 8.2 Release

I am trying to compile FreeBsd 8.2 RELEASE kernel # uname -a FreeBSD 8.2-RELEASE FreeBSD 8.2-RELEASE #2: Sun May 18 00:07:10 PDT 2014 Build the kernel # pwd /usr/src # make buildkernel ... it ...
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Error compiling buildroot

I updated my buildroot for the version "2014.08" (stable version) and I updated the Kernel version (3.12.26) of my project, when the buildroot try to build the linux-headers-3.12.26 package, occurs ...
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How to enable VESA framebuffer as default in NetBSD 6.1

When booting NetBSD, the old Tecra 720CDT that I have, works quite nicely in 1024x768x15 mode with vesa fb. I always have to activate VESA when booting the system: > vesa on > vesa 0x116 > ...
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CPU load and power management (frequency)

question background In my understanding the load value (shown e.g. by top) allows (together with the knowledge how many CPU cores the system has) a very quick assessment which share of the ...
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loading ath9k_htc kernel driver fails

could someone please point me in the right direction to get my external wireless stick (TL-WN722N) working on my Xperia Neo (haida) smartphone? So far I've done the following: I downloaded ...
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Debian Squeeze: TCP/ICMP stops working suddenly (R8169 Driver)

we suddenly see our NETWORKING stops (TCP/UDP/ICMP) in our client system. tcp: We tried reaching our server every 5 seconds.But , there was no connection establishment TCPDUMP REF: ...
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Why is Linux NFS server implemented in the kernel as opposed to userspace?

I was just wondering why the Linux NFS server is implemented in the kernel as opposed to a userspace application? I know a userspace NFS daemon exists, but it's not the standard method for providing ...
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“select” vs “depends” in kernel Kconfig

What are the differences in dependencies between select and depends on in the kernels Kconfig files? config FB_CIRRUS tristate "Cirrus Logic support" depends on FB && (ZORRO || PCI) select ...
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Why will plymouth not update?

I admit I don't update my kernel very often. I used to everytime a stable release of sys-kernel/gentoo-sources came out so I'm very adept at doing it. This last weekend I attempted to update from ...
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What exactly does struct nfs_unlinkdata do?

I been reading the source code of unlink() but i am stuck on nfs_unlinkdata and i can't find anything on it on the web. Thanks a lot for your help.
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HD 4800 lower fan speed

I've installed Linux Mint 17, most important thing for me is to lower the fan speed to 30% as I am doing in Windows because it's really too noisy. Note that the temperature stays at ~50°, so this ...
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Fatal error: linux/smp_lock.h: no such file or directory when trying to compile tiusb

I am trying to compile the TI-Graph Link USB Drivers? So I downloaded it, and ran make in the directory libusb. It produced the following: ~/Téléchargements/tiusb/tiusb-1.10$ make make -C ...
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real time kernel / low latency comes from the vanilla source

Does the vanilla source provide real time / low latency functionality ?
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NTPD Nanokernel

I had a couple of questions about the NTP Nanokernel as explained here: http://www.eecis.udel.edu/~mills/database/brief/nano/nano.pdf The big question is how does this Nanokernel manage to deliver an ...