The kernel of operating systems popularly known as Linux, or sometimes GNU/Linux.

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Does a fault in a kernel module necessarily result in a system crash?

Or is it possible to overcome the fault, since the code isn't in the monolithic part of the kernel?
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Does the kernel have a main() function? [closed]

I am learning device drivers and Kernel programming. According to Jonathan Corbet's book, there is no main() function in device drivers. So I two questions: Why don't we need a main() function in ...
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2answers
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Install kernel-devel of specific version in fedora 19

So I have different "installed" kernel versions from the running kernel version, on my fedora 19 machine. To give a more clear idea, here is my terminal output: [user@home ~]$ uname -r ...
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4answers
10k views

Can I create a virtual ethernet interface named eth0?

I am running Arch based on the Linux 3.10.5-1 kernel. The system uses the new de-facto naming conventions of ethernet interfaces enp*s* and wlp* etc. This is a problem however, as my educational ...
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0answers
428 views

PC sudden shutdown, Sensors show normal temps, Thermal event interrupts shows 1276

I'm experiencing sudden shutdowns on my Linux systems. Using Ubuntu 12.04, my kernel version is 3.5.0-37-generic #58~precise1-Ubuntu. Running a Acer M5 581t(G) with 6 gigs ram laptop. I have been ...
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1answer
287 views

Generate interrupts for purpose of stress testing

I'm testing the quality of a generated PWM signal on a Raspbery Pi. I would like to test how it behaves if there are lots of interrupts coming. Is there a way to fake interrupts or force 2000 ...
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1answer
803 views

Beaglebone Black Device Tree for LCD4 cape

The device tree for LCD4 cape is located at /lib/firmware/BB-BONE-LCD4-01-00A1.dts When I looked into it, the declaration of those GPIO buttons confuse me. There are five buttons according to ...
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1answer
92 views

Building Linux from Scratch stuck, incompatible sed version? [duplicate]

I am trying to build Linux from Scratch per LFS website While I was able to install all the packages until 6.7.1 without any error, I am stuck at Installation of Linux API headers (This is after I ...
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2answers
294 views

Strange temporary network outage in Linux

I'm facing a very annoying problem that I noticed a week from now and for which I can't find an answer: my network suddenly stops responding, usually coming back exactly 25 seconds later. I was using ...
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2answers
2k views

Linux (debian/testing) cannot boot after installing kernel 3.9.1

Today I wanted to upgrade the kernel on my debian/testing system from 2.6.32-5-686 to 3.9-1-686-pae. So I installed the image by sudo aptitude install linux-image-3.9.1-686-pae (or something like ...
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1answer
225 views

What value is stored in linux xtime variable?

Whenever I print the value of /proc/interrupts the value of rtc0 in IRQ8 which is for RTC shows only 1 interrupt on CPU0. I have read that when booting the value of the xtime variable is stored from ...
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2answers
444 views

Why CONFIG_NO_HZ is not set by default

In the Linux Kernel CONFIG_NO_HZ is not set. But an initial reading suggests that setting that option would be nice from a performance point of view. But reading some posts like this made me think ...
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1answer
91 views

Why can't new versions of kernel solve the backlight problem?

Currently I am using Linux 3.8.0-27-generic kernel on my Samsung laptop. I replaced grub configuration file with the following text to make backlight control work: GRUB_CMDLINE_LINUX_DEFAULT="quiet ...
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1answer
1k views

What is meant by interrupt remapping in Linux?

Can anyone explain what the interrupt remapping is? Would turning this feature off in the Linux kernel cause any problems, or bring any benefits?
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1answer
160 views

Efficiency of Linux Kernel [closed]

In a documentary, Linus Torvalds says that even in the future, if anyone wishes to make a new OS from the scratch, they could use the Kernel which he wrote. It was very inspiring. Is it true that ...
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2answers
1k views

Can system calls be interrupted?

Please comment on the following sentence: On the standard Linux kernel without the rt patch, interrupts can't interrupt ongoing system calls. The reason why our machine doesn't stop working ...
2
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1answer
495 views

Are time interrupts always followed by a scheduler call?

When a timer interrupt occurred the ISR is called to service the interrupt. Is it okay to assume that every timer interrupt ends with a call to the scheduler on which process should continue running ...
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1answer
57 views

CentOS - acts abnormal every week and causes my whole setup to be down, how can I rollback / restore back to one week?

I have CentOS and Red hat enterprise Linux running, where I have now working Google Apps Engine and related other Python web applications. Every week or depending on any Google Apps Engine latest ...
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0answers
90 views

boot updated kernel image on beagleboard

Boot updated kernel image on beagleboard. I had installed a kernel on Beagle-board to update image of kernel to it. I've used this command: $ sudo apt-get install linux-image-3.2.0.49-omap It ...
3
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1answer
766 views

What are PCI quirks?

I hear a lot about PCI quirks when reading about the Linux kernel, but no website explains or defines PCI quirks. What are PCI quirks?
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2answers
786 views

How can I know if the current kernel was compiled with a certain option enabled?

Is there a way to know if the kernel was compiled with a certain option activated (i.e. CONFIG_PROC_EVENTS=y) without having to pull out the kernel sources package and looking in the config file?
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0answers
212 views

Will there be any security problem to permit non-root user set up a loopback devices?

if the user has full access to the image file (iso or disk image), will there be any security problem to permit him set up a loopback device backed by this file ? % ls -al /dev/loop* ...
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2answers
3k views

How to 'strace' a unix domain socket?

Kind of hard to explain but I noticed when straceing the PID that has the socket open I cannot see any of the communication. How can I sit in the middle of a socket file to watch communication?
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Allocated Memory difference in xen guests after using Linux 3+ kernel [closed]

Can someone explain to me why there is a memory difference in Guests with the same configuration? Hypervisor: xen 4.2 64 bit VM1: Centos 5.7 with 2.6.18-274.el5xen Assigned memory from xen is ...
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1answer
65 views

Significance of certain folders in linux kernel tree

While going through Linux Kernel Source tree, found certain folders, explanation of which was not seen in the popular sites. Could someone tell why these folders are there like: block - This is not ...
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configure allowed_tcp_congestion_control via config files in linux kernel

I am trying to come up with a custom set of TCP congestion control variants as part of the tcp_allowed_congestion_control. I do have multiple variants on my tcp_available_congestion_control list but ...
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1answer
3k views

Is “sync” before drop_caches necessary?

I have read a lot of docs saying, it is good idea to do a sync before doing echo [1,2,3] > /proc/sys/vm/drop_caches. I am not able to understand why it is needed, since drop_cache is a ...
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1answer
139 views

what is the linux boot param “memmap” equivalent in freebsd

In linux kernel, there is an option to reserve a portion of system ram i.e memmap=512M$2G (boot param) Here 512M starting from 2G would be reserved and not available to OS What is the equivalent in ...
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2answers
45 views

Resuming the Linux Kernel Configuration

I am configuring a Linux kernel before I compile the code. However, after I was thirty minutes into answering the many questions concerning various kernel settings, I accidentally pressed Ctrl+C. I do ...
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1answer
729 views

How to log iptables as of kernel 3.9.0?

What is the right way to log iptables as of kernel 3.9.0? I can no longer append a logging rule such as: # iptables --new-chain droplog # iptables --append droplog --jump LOG --log-level info ...
0
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1answer
246 views

After upgrading to linux kernel 3.9, kde does not start correctly

I recently upgrade my debian from kernel 3.2 to 3.9. This leads to a strange problem. After booting to kernel 3.9, it directly goes to tty7 instead of kde login. I can identify that kdm is up and ...
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0answers
165 views

What changed between kernels 3.7 and 3.9 that affects LVM/RAID root file systems?

I'm trying to fix a (very messy) system that the user hosed by running a kernel upgrade from 3.7.10 to 3.9.6. the root file system is on an LVM volume on top of a software RAID array. The boot manager ...
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1answer
115 views

How can I find the Secure Attention Key (SAK) on my system and can I disable it?

In answer to My process was killed but I cannot understand the kernel notice, I was pointed to some documentation on the Secure Attention Key (SAK) on Linux. I have a embedded system generated using ...
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1answer
40 views

get Various types of address used [closed]

How to get various address ranges of a running machine or a crash dump? User virtual address Physical address Bus address Kernel logical address Kernel virtual address I don't need the bus ...
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2answers
101 views

Download the Complete Linux Kernel Collection

I am wanting to download EVERY version of the Linux kernel as source code, Debian files, and RPM files. Where can I find a single site where I can download them all at once? If that is not possible, I ...
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2answers
2k views

How do I get a linux kernel patch set from the mailing list?

I don't subscribe to the linux-kernel mailing list, but I want to get a set of patches that were posted a few weeks ago and apply them to my kernel for testing. I'm very familiar with patching, ...
3
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1answer
168 views

What do the fields in the libata device probe line in dmesg mean?

When the kernel boots, it prints out lines like this for each SATA device: [ 0.919450] ata2.00: ATA-8: ST2000DM001-1CH164, CC24, max UDMA/133 [ 0.919487] ata2.00: 3907029168 sectors, multi 16: ...
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2answers
568 views

Enabling UTS Namespaces in the Linux Kernel

When configuring the Linux kernel, what are the advantages and disadvantages of enabling UTS namespaces? Would the new system be harmed if UTS namespaces were disabled?
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1answer
3k views

Understanding RCU when Configuring the Linux Kernel

I am configuring the Linux kernel version 3.9.4. I am being asked questions about RCU (seen below). Specifically, what are each of these and what are the advantages and disadvantages of enabling or ...
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0answers
204 views

How to set CONFIG_PREEMPT_NONE in RHEL 6.4 (linux)

I am trying to tune the RHEL6.4 Kernel to handle server style load for of my application. With RHEL 6 scheduler has been changed to CFS and with RHEL 5 my application works fine. I would like change ...
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2answers
502 views

mount options shown in /proc/mounts

IIRC then the mount options shown in /proc/mounts have changed. Some time ago acl and user_xattr were shown, now it seems that only noacl and nouser_xattr are shown if these features are turned off. ...
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2answers
3k views

Determine if reboot is required to update kernel?

I am running a server which runs on CentOS with cPanel (latest version) and I have it set to automatically update using yum. Since it needs to be rebooted in order to update the kernel (and possibly ...
2
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1answer
3k views

net.ipv4.conf.all.mc_forwarding: why is my access denied?

On Debian 12.04 LTS I am trying to access the key net.ipv4.conf.all.mc_forwarding by doing : sudo sysctl -w net.ipv4.conf.all.mc_forwarding=1 But every time I am doing this, I get the message ...
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3answers
2k views

how to get network QoS statistics in linux kernel?

Is there a way to get the bandwidth, delay, jitter collision, error rate and loss rate of a certain link through the interface on a local machine? let's say my machine is connected to a network via ...
2
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1answer
93 views

What are some of these directories in the Linux kernel src?

When I uncompress the Linux kernel source code from Kernel.org, there are many folders. I know what most of them contain and their purpose. However, I cannot figure out or find on the Internet the ...
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3k views

Can ps display only non kernel processes on Linux?

How can I ask ps to display only user processes and not kernel threads? See this question to see what I mean...
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1answer
55 views

Theoretical possibilities for cpu emulation built into boot-loader or kernel?

Is it a crazy idea to somehow make a blend of grub and qemu in order to boot linux kernels or any kernel of any cpu type supported by qemu or the built-in cpu? I know it might be impossible to detach ...
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1answer
104 views

Kernelpanic Fedora 18 with kernel 3.9.2-200

Since upgrading to kernel 3.9 I now get this error every time at start up: BUG: unable to handle kernel NULL pointer dereferences at (null) IP[<ffff8800ca93bfcd>] 0xffff8800ca93bfcc PGD 0 ...
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1answer
5k views

using devtmpfs for /dev

I have noticed the following option in the kernel: CONFIG_DEVTMPFS Device Drivers -> Generic Driver Options -> Maintain devtmpfs to mount at /dev And I see that it is enabled by default in ...
2
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1answer
514 views

I'm failing to set up a wireless Access Point (AP)

I'm trying to get this card to be an access point, and am failing. I tried various Ubuntu releases, and checked on both ARM and i386. The kernel version I used is 2.6.35, and there is no Network ...