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

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1answer
58 views

Difference in execution of init with embedded vs. external initramfs?

I'm building a very minimal linux system that just consists of the kernel (v4.1-rc5) and an initramfs populated with busybox (v1.23.2). It works fine for the most part, but I observe a difference in ...
1
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1answer
56 views

Linux kernel: meaning of source-tree, in-tree and out-of-tree

What do the terms "in-tree" and "out-of-tree" exactly mean? Also, does "source tree" specifically refer to the official kernel released from / maintained at kernel.org or is it a more general term ...
113
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3answers
8k views

What does the Windows flag in the Linux logo of kernel 3.11 mean?

I've just installed kernel-3.11.0-1.fc20 for my Fedora 19 installation. During the rebooting progress, I saw the Linux logo with a Windows flag in it, what does it mean? The Fedora 19 is installed ...
2
votes
1answer
63 views

How can I prevent a module from flooding my kernel log with useless output?

I'm using the atmel_mxt_ts module, and it floods my kernel log with useless status messages, about 10 per second. I'm worried this will make my journal massive and cause unnecessary writes to my SSD. ...
2
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0answers
80 views

How to explain strange kernel messages?

I have a server running on Debian Wheezy 3.2.68-1+deb7u1 x86_64. Lately strange records in /var/log/messages appeared. First messages of this log starts just after server reboot. 6.222.18 LEN=44 ...
1
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1answer
81 views

Is the Linux kernel affected by paging?

Is the whole kernel always loaded to RAM whatever the size of the RAM? In other words, can the Linux kernel be affected by paging (some part of kernel reside in virtual memory)?
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2answers
935 views

SIOCSIFADDR: File exists after upgrading kernel

Since upgrading my (Gentoo) kernel from 2.6.38 to 3.3.8 (via oldconfig), I can't get the network on eth0 up anymore. It reports "SIOCSIFADDR: File exists" with a number of other SIOCSIF* errors that ...
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0answers
26 views

How to debug freeze at start, output of syslog

Every now and then, my computer freezes while starting. I can see some "Oops" in /var/log/syslog, but from there I am not sure what to do to try and fix the problem. Jun 5 12:47:40 fulla kernel: [ ...
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1answer
109 views

How does the Linux kernel initialize console graphics?

Observation: I switch on a Linux box Boot loader displays its output on screen Boot starts with first output messages Screen goes blank, and never comes back on. Note: this is about the console, ...
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0answers
258 views

how to make LVMs at available boot? kernel panic - dracut cannot find logical volumes after kernel upgrade in CentOS 6.6

I have a centoOS 6.6 vmware vm that I ran yum update on which upgraded the kernel after reboot, I started getting this: dracut Warning: No root device "block:/dev/vg_myhost/lv_root" found dracut ...
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0answers
53 views

Qemu Linux(kernel with debugging symbols) and ARM

I'm looking for a Linux ARM kernel, disk image and initrd that is compiled with debugging symbols. I'm looking to debug the kernel using the qemu and gdb. Could you point me to an arm linux image that ...
5
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1answer
2k views

Kernel booting stops right after “Uncompressing Linux…”

I'm trying to bring up an ARM-based board. I've got U-Boot working but can't seem to get the kernel to load. Most of the time it only goes as far as: Starting kernel ... Uncompressing Linux... A ...
2
votes
1answer
89 views

Linux kernel patches: can I skip some?

I have the source of Linux 3.4.0 to which I added some modifications. I know that here (ftp://ftp.kernel.org/pub/linux/kernel/v3.x/) I can find all the 107 patches that need to be applied to my source ...
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0answers
23 views

System accounting misbehaviour on MacOS X (Yosemite)?

On all my Unixes (CentOS, FreeBSD, MacOS X) I activate the system accounting as a basic security rule. On MacOS X (Yosemite, 10.10.3) I see a misbehaviour I am investigating to fix. Everytime I run ...
3
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3answers
3k views

Ping IP works, nslookup fails. New Kernel

I am compiling my own 3.14 kernel. I fear I may have left out some important networking feature to get DNS working. I can't resolve domain names. I can ping my DNS server. I can resolve using that ...
4
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3answers
4k views

How to add more /dev/loop* devices on Fedora 19

How to add more /dev/loop* devices on Fedora 19? I do: # uname -r 3.11.2-201.fc19.x86_64 # lsmod |grep loop # ls /dev/loop* /dev/loop0 /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 /dev/loop5 ...
0
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0answers
40 views

High read/write system call time

I am facing a weird problem with one of process taking more processing time in one system comparing to other systems. Most of the time is spending on read and write system call on problem host. I am ...
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2answers
68 views

Triggering hardware interrupts by connecting parallel port pins 9 and 10 does not work

I want to trigger hardware interrupts as described in the book Linux Device Drivers by connecting pins 9 and 10 with a wire. I tried that but apparently there's no interrupt beeing triggered: cat ...
1
vote
1answer
3k views

Driver install, kernel source not found

I am trying to install a NVidia Cuda driver on a Amazon EC2. GPU instance (Amazon Linux AMI (HVM) 2013.09.2 - ami-e9a18d80) following the instructions laid out in a blog. It worked for the last two ...
6
votes
1answer
4k views

“Argument list too long”: How do I deal with it, without changing my command?

When I run a command like ls */*/*/*/*.jpg, I get the error -bash: /bin/ls: Argument list too long I know why this happens: it is because there is a kernel limit on the amount of space for ...
3
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0answers
60 views

Book for understanding latest Linux kernel [closed]

I want to understand the Linux kernel. For this I have the book "UnderStanding the Linux Kernel, 3e". Inside the book I have found that the book has written based on Linux kernel 2.6. But as my ...
0
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2answers
1k views

How to disable core dump generation in Centos (cPanel Server)?

I want to disable core dump generation, How can I disable it ? One of the website keeps generating core dumps every second and eats up all the disk space. OS Details: CentOs cPanel Server ...
3
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2answers
185 views

What are the programs/commands which the magic SysRq key invoke?

From Magic SysRq key The magic SysRq key is a key combination understood by the Linux kernel, which allows the user to perform various low level commands regardless of the system's state. It ...
5
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2answers
881 views

Compiling the kernel with default configurations

Assumptions: The platform: anisha@linux-dopx:~/> uname -a Linux linux-dopx 2.6.34-12-desktop #1 SMP PREEMPT 2010-06-29 02:39:08 +0200 x86_64 x86_64 x86_64 GNU/Linux The kernel downloaded is the ...
5
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4answers
4k views

Prevent claiming of novelty usb device by usbhid so I can control it with libusb?

I have a USB rocket launcher that I wish to experiment with through libusb. However, libusb cannot claim the interface; presumably because the output of usb-devices lists 'usbhid' as the driver for ...
1
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1answer
107 views

Where is routing table stored internally in the Linux kernel?

When I execute route -n, from where exactly (from which structs) is the information displayed retrieved? I tried executing strace route -n but I didn't help me finding the right place it's stored.
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0answers
15 views

Why there is PPPd instead of all PPP software in kernel?

Are there any reasons why the need of PPP software separation from kernel and process (PPPd)?
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3answers
2k views

Linux freezing guess: keyboard & mouse (Archlinux and Ubuntu)

Linux on my PC is freezing a few seconds after startup. I am unable to use the mouse / keyboard. Neither Ubuntu nor Arch do anything after a few seconds. Windows has been running fine for years now. ...
0
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2answers
132 views

how to untar file in linux red hat?

I am compiling linux red hat stable kernel on red hat linux and the error which I am facing is as below
2
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1answer
1k views

Kernel Backport for Debian Jessie?

I installed the 32 bit version of Debian Jessie (8.0) on an Asus X205TA. The Asus X205TA laptop is quirky like a lot of Intel Baytrail Atom laptops/tablets in that it has 32 bit EFI but a 64 bit ...
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0answers
22 views

Using dkms to patch kernel

I need to apply a kernel patch(https://lkml.org/lkml/2015/3/31/929) to get my touch-pad working properly. I am thinking that I should be using dkms, to do this. Most of the stuff I am reading is about ...
2
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1answer
170 views

bdl_pos_adj: set IRQ timing workaround for hda-intel

I get following errors in my logs: kernel: snd_hda_intel 0000:00:1b.0: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj Google found some old posts here and ...
2
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0answers
514 views

Delayed write scenario

I was reading "The Design of the UNIX Operating System" by Maurice J. Bach and had a confusion. Suppose a process requests for a buffer for disk block number 18. The kernel searches for a free buffer ...
0
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1answer
41 views

Kernel modules for compiled kernel

I cannot find kernel-headers. For the first time I compiled and installed the latest kernel (4.0.3) on my Debian Wheezy, and now I am trying to install ndiswrapper using module assistant. For that, ...
0
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1answer
38 views

Why does user mode linux spawn 4 processes?

If I start User Mode Linux with this command: ./kernel32-3.19.8 ubda=./Debian-Wheezy-x86-root_fs mem=128m On Debian GNU/Linux 8 (jessie) with one CPU core, why do I see 4 processes in top: 1608 ...
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0answers
49 views

Linux Driver for USB “reverse” mass storage device

I'm developing a USB device that I want to read and write in virtual filesystems that are in my computer. Basically the device needs to be able to read, write and get the virtual filesystem size. Some ...
0
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2answers
61 views

how to check a kernel version which was used when building package

I use apt when downloading packages from Ubuntu repositories. How can I check which kernel version was used when building package? When it is important (kernel version of the build server vs. kernel ...
0
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1answer
132 views

Not able to reinstall the kernel or to use the latest version

On a ubuntu server, I try to di "sudo modprob" and I have this error : $ sudo depmod [sudo] password for deployer: depmod: ERROR: could not open directory /lib/modules/3.8.0-38-generic: No such file ...
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0answers
72 views

READ DMA Error after Installing CentOS 7

I have been trying to install CentOS7. After I installed it, I see the following message sporadically. ata2.00: exception Emask 0x10 SAct 0x0 SErr 0x4050000 action 0xe frozen ata2.00: irq_stat ...
0
votes
1answer
79 views

Downgrade Debian kernel

I have a requirement to install Debian kernel 3.2.65-1+deb7u2. I cannot seem to find the kernel. I have taken the following steps: Installed kernel 3.2.68-1+deb7u1. Downgraded the kernel to ...
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2answers
55 views

why do some network cards need to load external firmware?

I have read this question/answer, but I still do not understand why some network cards work perfectly well without any additional firmware, whereas others need to load firmware to work. As a specific ...
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0answers
70 views

Limit system processes using cgroups

My server runs several dozens of processes that are not in my control (mostly monitoring software). According to my application logs, sometimes some of the third party processes try to allocate too ...
0
votes
1answer
26 views

GNU\Linux clustreing , Which level? Which application? [closed]

I need to start GNU* clustering, But I have problem, Which level: DB level? (replication) file system? (distributed) process level ? (such as intel fortran for civilization softwares) new process ? ...
0
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1answer
19 views

Uprobes Status on the present linux kernel

I know uprobes was introduced on kernel 3.5 has it survived or is it dropped, is it still available on kernel 4.x
81
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3answers
156k views

How do you empty the buffers and cache on a Linux system?

Prior to doing some benchmarking work how would one free up the memory (RAM) that the Linux Kernel is consuming for its buffers and cache?
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2answers
7k views

Building example device driver error: insmod invalid module format

I am following the tutorial @ http://www.embeddedsystemonline.com/home/embedded-system/embedded_linux/lab3-linux-device-driver on step #7 of this tutorial, $ cd ...
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0answers
42 views

RHEL6 Idle Thread Behavior

I am doing some cpu performance profiling with the perf tool on a RHEL6 box running weblogic12g. It looks like the idle threads are presented as native_safe_halt in the stack profile but ...
0
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2answers
64 views

why can't we install application compiled for Ubuntu, on Linux mint, or some other distros with same kernel?

When i try to download some applications like VLC, it shows in download options, various Operating systems which includes Linux mint, Ubuntu etc. Though Linux mint's kernel is from Ubuntu, still they ...
3
votes
4answers
142 views

None of the linux programs work except 'cd'

Before stating the question, here's what I did and observed before the problem started: On a fedora 18 Xfce, I tried compiling 3.6.10 kernel with a cdv driver, After many attempts, it finally ...
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0answers
17 views

Filesytem errors during boot

I am using OMAPL138 and kernel version 2.6.37 and I would like to improve the boot time of my system. I made some progress on this, but I still have some errors which may be causing delay in the boot ...