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

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rewrite existing file so that it gets replaced by new version atomically, only once fully written

I vaguely recall reading somewhere that there used to be, in some Unices a way to open an existing file for writing, with a flag that asked the kernel to use the old version (for other processes ...
2
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1answer
1k views

create a debian installer with custom kernel

First what I need to do is install a debian on a 3300mx computer which is based on a vortex cpu. The problem is the debian installer always crash because the required drivers are in the kernel as ...
2
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1answer
141 views

Is it possible for grub2 to detect some specific CPU features and choose a proper kernel to boot?

I want to configure grub to check some CPU features on startup and choose a proper kernel to boot (e.g. multiple cores -> kernel with SMP support). Is it possible? If so, then how do I do it?
4
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4answers
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Stripped down Kernel for a Laptop

I am a Linux noob, but I am willing to learn. My immediate objective is to compile a small kernel for my laptop without sacrificing usability. I am familiar with the kernel compilation steps (don't ...
1
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1answer
942 views

Is there a way to increase the 20 multicast group limit per socket?

As the title says, is there a way to increase the limit of 20 multicast groups that you can join on a given socket? Is there some system setting that I am missing or is there some hard limit which ...
2
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1answer
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libusb_init() returns -99

I have successfully built both libfreenect (driver for Xbox Kinect) and libusb (which is a dependency). However, if I try to open the Kinect using the freenect_init(...) function, it returns -99. I ...
4
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1answer
3k views

How to update Debian kernel to latest in backports

I have a machine running Debian stable, and I'd like to update the stock kernel to the latest kernel available in the backports repository. There are many kernel-related packages and virtual ...
2
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0answers
187 views

What are the current differences between tuxonice and µswsusp?

I tried to find out what is the current comparation between TOI and µswsusp. Unfortunately I could not find any recent information about the state of hibernation in Linux and how TOI compares to ...
4
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1answer
2k views

What is the difference between /proc/self/stack and output from pstack?

I have been looking through the documentation for /proc and the "stack" object being a new'ish object in proc, I have also looked through the kernel commit to create it -- however the documentation ...
4
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1answer
2k views

Debian 6.0 system with 2.6.39 kernel dropping packets, sandy bridge hardware

I recently migrated an existing Debian system to new hardware, a core i3 chip running on an intel sandy bridge motherboard. I’m experiencing a very strange problem; when I ping my router, about 50% of ...
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5answers
16k views

Why is kworker consuming so many resources on Linux 3.0.0-12-server?

Last Friday I upgraded my Ubuntu server to 11.10, which now runs with a 3.0.0-12-server kernel. Since then the overall performance has dropped dramatically. Before the upgrade the system load was ...
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2answers
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What is the need of the struct thread_info in locating struct task_struct?

While reading through the Linux Device Drivers, I could understand that the Process Descriptor (of type struct task_struct) has all the info regarding a particular task. The process descriptors are ...
2
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1answer
518 views

regarding shared memory behaviour

Noticing a strange performance behaviour while using shared memory that are file backed (i.e open user defined file and mmap() the same into process space). While doing a memcpy() into the shared ...
6
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1answer
2k views

Custom kernel: fails to load firmware when module built-in

I'd like to have all my modules built-in, but this fails with iwlagn: iwlagn 0000:03:00.0: request for firmware file 'iwlwifi-6000-4.ucode' failed. iwlagn 0000:03:00.0: no suitable firmware found! ...
1
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1answer
778 views

How can nfs service in the kernel be disabled?

How can nfs service in the kernel be disabled? As far as I can see there are no userland utils # find / -name nfs* -print /sys/kernel/slab/nfs_page /sys/kernel/slab/nfs_inode_cache ...
14
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3answers
4k views

Increasing kernel memory size

I have an embedded board with 512MB of RAM running Linux 2.6.29 and UBoot bootloader. But the kernel is able to utilize only 128MB of RAM. I tried changing the value of XCODE_MEMSIZE, which I think ...
1
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1answer
995 views

Linux kernel 2.6.38 compilation error

When I try to compile the Linux 2.6.38 kernel on my Linux PC, I get: $ make defconfig $ make I get: ubuntu/ndiswrapper/iw_ndis.c:1966:2: error: unknown field ‘num_private’ specified in initializer ...
3
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1answer
2k views

How to capture from instensive pro in Ubuntu, Fedora, CentOS using HDMI interface?

I am trying to use PCI-X1 capture card (intensiy pro) using Ubuntu 10.04 (now) / 11.04 (failed) or Fedora (failed). None of them is yet capturing. I did my best but now i need some backup on this. ...
5
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1answer
4k views

What is a “watchdog reset”?

After reading this question, I was a little confused; it sounds like some daemon reacting by rebooting a system. Is that right? Is it a common occurrence in embedded *nixes?
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2answers
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How do I cause a watchdog reset of my embedded Linux device

Is there a command like vi > out vi | out That I could use to cause a watchdog reset of my embedded linux device?
2
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1answer
1k views

Unable to boot custom kernel

I am using ubuntu 11.04 I have a custom 2.6.36.4 kernel source (say in linux_src) Did make mrproper Copied my current configuration from /boot to linux_src/.config Did a make menuconfig, instructed ...
3
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1answer
1k views

Using syslog from a kernel module

I am writing a linux kernel module to report statistics and send some log messages. Can I use syslog to accomplish this job? Or is printk the only way?
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3answers
860 views

How can I reconfigure my Ubuntu PC's 2.6.37.6 kernel to shrink it to 950 KB or less?

I need to recompile the kernel with minimum configuration so that after compiling its size stay below 950 KB and it should boot correctly after compilation. I need to compile with minimum possible ...
7
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1answer
786 views

Grubby fatal error in Linux kernel installation

I have compiled Linux kernel 2.6.24.6 from source (without problem) and tried to install it. Specifically, after unpacking the Linux source code, I did make && make modules to compile. ...
3
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2answers
346 views

Is there a different linux kernel for different architectures?

If I want to build a custom kernel for an ARM architecture, do I need to : a) Download the kernel from kernel.org, make changes to the kernel, build it using some cross compiler (like code sourcery ...
2
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2answers
367 views

UDP multicasting broken after kernel update

I've got an embedded system which is running a stripped down Gentoo userland with a manually build kernel. The system acquires data from a PCI card and sends it out to an UDP multicast group. All ...
3
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1answer
165 views

Does linux have Blackbox like mechanism when system crashed in embeded linux?

In embeded linux, some times after the system crashes, we hope there is a blackbox (will record the key info before the system restart) , in linux, is there have such kind of mechanism to record the ...
2
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1answer
118 views

Is there any method to mount a block of memory as a filesystem in linux?

I have a question,in linux, is there any method to mount a block of memory as a filesystem? For example, in X86 architecture, when power on, I reserve a block of memory about 8 Mbytes, and then when ...
4
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2answers
19k views

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 ...
4
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2answers
330 views

Non-interactive configuration of linux kernel

Is there any method to configure linux kernel in such way (just an example): make config CONFIG_OPTION=y && make config CONFIG_OPTION1=no CONFIG_OPTION3=64 CONFIG_OPTION4=/path/ and all the ...
2
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1answer
216 views

rpm content compress

My default kernel rpm has 12mb size, for some reasons I compile a custom kernel and make rpm from that(make rpm command). However, my custom kernel rpm size is 96mb. I look inside default rpm, in ...
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2answers
512 views

How to use a custom crypto algorithm in ipsec?

I wrote a custom algorithm using the kernel crypto API (by modifying the existing SHA1 and DES algorithms), compiled and added the .KO object to kernel. How can I use my algorithm in ipsec and other ...
13
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1answer
10k views

Buffer size for capturing packets in kernel space?

Going through the man page of tcpdump, it seems kernel can drop the packets if the buffer is full. I was wondering if: that size is configurable and/or where can I see the size for my distro? From ...
12
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2answers
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How to include local header files in linux kernel module

Say I have a module mymod with source files as follows: src/mod/mymod.c src/inc/mymod.h I try to include mymod.h as follows #include <mymod.h> My makefile contains EXTRA_CFLAGS= ...
5
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3answers
3k views

ACPI problem with recent kernels

In recent versions of popular Linux distributions (Ubuntu, Fedora, Mint, Debian) I always have to put acpi=off into the kernel parameter list before I want to boot the computer. This happens to both ...
4
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2answers
495 views

How to configure CONFIG_DEFAULT_RELATIME to disable relatime

Since linux 2.6.30, filesystems are mounted with "relatime" by default. In this discussion, Ingo Molnar says he has added the CONFIG_DEFAULT_RELATIME kernel option, which: makes 'norelatime' the ...
8
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2answers
6k views

Cleancache vs zram?

I have an old laptop here with only 512 MB of RAM. Since a few kernel releases, I am using zram to convert 256 MB of it to a compressed ramdisk which is then used as swap. This has proved to be very ...
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1answer
2k views

When was `relatime` made the default?

What is the first Linux kernel release to set relatime as the default mount option?
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2answers
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Why do I get this error installing virtualbox-4.1 on Arch?

I'm trying to install Virtualbox 4.1 from the .run file since Pacman had the 4.0 version only. But when I try installing the file using sh filelocation/filename.run, it gives me the following error- ...
4
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2answers
349 views

Is there a vanilla kernel configuration?

A question on Ask Ubuntu asks if there's a vanilla kernel for Ubuntu. Its answer is there is a "Mainline" series of kernels for Ubuntu that use vanilla files with Ubuntu configurations. But how ...
2
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1answer
179 views

Fedora 15 address collision on Compaq CQ41?

I keep getting an address collision warning at boot time, between ACPI and Video Rom. If I add acpi=off to grub.conf the error goes away, but then I have no power management (battery icon, proper ...
0
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1answer
304 views

Where to find this specific source (centos 2.6.18-53.el5PAE)

okay all my looking around on the normal kernel site ftp can't find it. I need specifically, the PAE version. I am compiling virtualbox and if you don't use the right source you get this lovely: ...
2
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1answer
2k views

Linux source, where are sys_umount and sys_mount system calls? [duplicate]

Possible Duplicate: Understanding the linux kernel source I am sure that I must be missing something, here. I cannot for the life of me find the source code for these system calls. I can ...
16
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4answers
693 views

What is new in Kernel 3.0?

I understand this is somewhat less Ubuntu related, but it affects it. So,what is so new about it that Linus decided to name it 3.0? I'm not trying to get information about the drivers that got into ...
4
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3answers
186 views

can i modify an .rpm-based system to use .deb files, apt-get and debian/ubuntu repositories?

I recently ran into trouble when installing Debian on a netbook. There were three major hardware/kernel issues that I didn't feel like fixing, and since every single forum/wiki writeup reported the ...
5
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1answer
2k views

Silent booting Linux from u-boot

For security reasons I have to boot Linux from u-boot with all output hidden (silently) until a password is entered. I've configured uBoot to do this correctly using the CONFIG_AUTOBOOT_KEYED macro ...
0
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0answers
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Make kernel detect garmin device

I'm trying to connect a usb garmin forerunner device to my system, but the usb device is not detected. I have loaded the following mods: garmin_gps 11544 0 usbserial 25449 ...
2
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1answer
3k views

What does 'Invalid module format' mean?

After executing... sudo modprobe rt3572sta I get... Invalid module format What does it mean? I'm trying to get Wusb600n v2 working on Lucid Lynx. Does it mean that kernel versions aren't ...
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3answers
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Linux Kernel logical address space organisation

According to "Write Great Code" in almost all OS run time memory is organized into following regions: OS | Stack | Heap | Text | Static | Storage/BSS [In increasing address fashion] User ...
2
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2answers
413 views

Fedora 15 i686 report only 2.6 GB RAM

I have laptop Asus N53SV with 4 GB of RAM, i7 with integrated card and dedicated GPU. My problem on Fedora is that system reports only 2.6 GB RAM. I know that I should use kernel with PAE but even ...