Tagged Questions

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

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4
votes
3answers
7k views

mount.cifs : mount error(12) : Cannot allocate memory

I encountered this problem a while ago when upgrading my kernel but put off upgrading until now. On my system I can happily mount network shares using CIFS running kernel 3.7.10, however when I've ...
1
vote
1answer
51 views

What software allows the change of runtime-environment, while keeping the same kernel running?

I know that with a GNU/Linux distribution you can switch between different distributions at runtime when they use the same kernel or the kernel is compatible between 2 or more different distributions; ...
6
votes
2answers
219 views

Location of the kernel binary (when not in /boot)?

I failed to find the kernel binary in the standard location in /boot. I've also searched the whole file system for vmlinux or bzimage find / -iname vmlin* find / -iname bzimage However, this is an ...
2
votes
1answer
530 views

GRUB2 Insert additional kernel modules

GRUB2 doesn't have the menu.lst file. How do I configure a boot script. During boot, I hit E on the kernel image that I want to modify and make my modifications. But I would prefer to make the ...
5
votes
2answers
344 views

What would I get when sudo a kernel-destructive program?

It suddenly comes to me how easy it will be for a sudoer to crash the kernel, so I tried something like this: #include<stdio.h> int main(){ printf("hello world"); int a; ...
3
votes
1answer
247 views

What is the maximum allowed number of TTY, is it defined anywhere in kernel headers?

What's the maximum allowed number of TTYs? I found pty.max, but is there anything similar for TTYs? Or is it defined as a fixed value in kernel headers, I couldn't find that
2
votes
2answers
2k views

After upgrading the kernel, the sound no longer works

I have updated the Linux kernel on my system to Linux 3.11-2-amd64 #1 SMP Debian 3.11.10-1 (2013-12-04) x86_64 GNU/Linux. Having done that, the sound no longer works. Distribution Info(cat ...
2
votes
1answer
264 views

How can I run gdb in one machine and run kgdb kernel in another machine?

I want to run two machine: debugged machine: compiled kernel with kgdb option. debugger machine: for running gdb How can I debug machine 1 from machine 2?
3
votes
2answers
144 views

How to fake a filesystem that cannot be mounted by others

I'm currently working on a project. There's an Ubuntu Linux system installed on a disk, DA, mounting the other disk, DB. What it requires is that DB can be only mounted by DA in order to prevent data ...
6
votes
2answers
323 views

what's the format spec for `ss -D `?

Background of the question: I am trying to sum up the total bandwidth, but ss -i cleverly converted numbers to more readable format like Kbps/s or Mbps/s, which is not accurate. So does ss -o with ...
0
votes
1answer
40 views

HDD indicator blinks when I run out of memory, but I have no swap configured [duplicate]

I'm running Arch Linux, with 8 GB memory and no swap defined. Sometimes it ran out of memory, then my system get a little bit stuck, and I can see the HDD indicator blinking. Then I restart X, which ...
3
votes
4answers
2k views

Is it necessary to reboot after a kernel upgrade (via APT)?

I have been wondering this for quite a while. Let's say that you have a Debian server that you keep updated via APT. Usually (every 1-2 months) there are some kernel updates, which will update the ...
1
vote
0answers
502 views

Qemu: No file system could mount root (unable to mount roofs)

In Linux, I've created the root file system (rootfs) by following commands: dd if=/dev/zero of=ramdisk.img bs=1M count=4 mkfs.ext2 ramdisk.img sudo mount -o loop ramdisk.img rootfs sudo cp init ...
1
vote
0answers
79 views

Kernel IPsec SA database: FIFO instead of LIFO

When processing an IP packet, the kernel looks into the security policy (SP) database to determine whether it is to be protected with IPsec. If the identifiers of the packet (e.g. IP addresses, etc.) ...
7
votes
5answers
4k views

Given a kernel ATA exception, how to determine which physical disk is affected?

I woke up this morning to a notification email with some rather disturbing system log entries. Dec 2 04:27:01 yeono kernel: [459438.816058] ata2.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x6 ...
-4
votes
1answer
61 views

when update kernels do they close bugs?

I'm not an expert in linux but when I upgrade my kernel to latest stable one which is 3.12.2, does it close all security bugs? How linux security bugs be closed? by installing newer kernel or how ...
4
votes
2answers
1k views

Capturing key input from events device and mapping it (toggle TouchPad key is unmapped)

I have a Lenovo IdeaPad Yoga 13 with Ubuntu 13.10 Installed. The device has a "Toggle TouchPad" button on the keyboard (F5). The keyboard's F* buttons are reversed (so to get F5, I need to press Fn + ...
2
votes
1answer
166 views

Where in the linux kernel sources can I find a list of the different keyboard scancodes?

I was looking for a list of keyboard scancodes in the linux kernel sources, but I did not find anything. Does someone know where to find these? Especially the USB scancodes would be interesting.
0
votes
2answers
436 views

Mainline kernel supported Raspberry Pi competitor? (no GPU needed)

The Raspberry Pi uses its own kernel fork. For a headless server (no GPU needed), is there a device with similar specs, performance-wise, that can use the vanilla mainline kernel from kernel.org?
3
votes
0answers
501 views

Debian driver needed for Intel ICH7M SouthBridge I/O controller

I am using a motherboard based on this architecture. http://www.intel.com/content/www/us/en/intelligent-systems/navy-pier/embedded-intel-atom-n270-with-mobile-intel-945gse-express-chipset.html I ...
0
votes
0answers
227 views

Doubt when compiling USB/IP drivers

I need to install a USB 3G modem to a Windows virtual machine (running on OVM). The modem will be plugged on a Linux host. (Would Windows be easier?) I don't understand what the following README file ...
0
votes
0answers
82 views

PPPD hangs, running over console port

I am trying to run the PPP daemon on the console port of my board which has p2020 processor with Linux kernel 2.6.32. After running ppp interface ppp0 is not coming up and I get an error pppd blocked ...
3
votes
2answers
211 views

How to measure PCI-Express bus usage?

I'm looking for a way to find out if PCIe bus is the bottleneck or not. It's not a problem to measure how much bytes was transferred through any particular NIC: Is there a way to find how much ...
0
votes
1answer
2k views

bnx2: Can't load firmware file “bnx2/bnx2-mips-09-6.2.1b.fw”

I just compile the kernel 3.10.19 from kernel.org Support for bnx2 is enable. On my server when I try to start the eth0 interface I got the following error : bnx2: Can't load firmware file ...
21
votes
3answers
997 views

If computers start counting at 0, why does the init process have a pid of 1?

Not much to put here in the body, the question is self explanatory.
0
votes
1answer
151 views

what is a Kernel? [closed]

I'm learning Unix from the Unix Architecture book by Maurice J Bach. So if my question seems too stupid, please do bear with it. I read a few related questions but I would like a more simple ...
0
votes
1answer
746 views

CentOS 6.4 Kickstart bootloader problem

I am installing CentOS 6.4 via a kick start file that looks like this in my build: # install the bootloader (GRUB) bootloader --location=mbr --driveorder=sda --append="crashkernel=auto" After the ...
1
vote
1answer
66 views

I/O brings a machine to its knees [closed]

Why, on every Linux I've used, when a program is really I/O bound, it bogs the machine down? It just happened when I (accidentally) tried to make gcc compile a (valid!) 50Mb C file. GCC was so I/O ...
2
votes
0answers
715 views

“Kernel panic - not syncing” after building Centos-6/elrepo 3.10.19 kernel from source

I need to rebuild the Centos-6 / elrepo 3.10.19 kernel from source. Background: the GVision touch screen drivers are incompatible with kernels > 3.8 and require source code patches to add code to ...
1
vote
2answers
127 views

How do I enable kernel option MMC_UNSAFE_RESUME

I am trying sleep and wake up my Kobo Mini ebook reader manually by using the command rtcwake. The reader is using busybox. cat /proc/version gives me this output: Linux version 2.6.35.3-850-gbc67621+ ...
0
votes
1answer
57 views

auditctl reports “File system watches not supported” on a very old system

When I run auditctl -l I got: # auditctl -l No rules File system watches not supported And I've already have AUDITSYSCALL enable in kernel, # zgrep AUDIT /proc/config.gz CONFIG_AUDIT_ARCH=y ...
0
votes
1answer
80 views

What kernel for ARM architechture, Linux or BSD? [closed]

I'm a computer sciences student and recently started a project with the engineering department that involves an onboard ARM processor, the question is what sort of operating system, kernel and ...
5
votes
1answer
640 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?
0
votes
1answer
47 views

Can the kernel be moved to a different mtd while the system is running?

I am attempting to do a full update on a mobile Linux Arm device. I have successfully pivoted my file system root and have been able to flash a new file system to that mtd. What I would like to ...
0
votes
1answer
346 views

Ubuntu 12.04.1 LTS - /boot is using 98.4% of 193MB

I have a problem. I have noticed that my VPS is saying : => /boot is using 98.4% of 193MB Looks like something went wrong, doesn't it? I have tried to run dpkg -l | grep linux to check what's ...
12
votes
3answers
12k views

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 ...
2
votes
3answers
92 views

What is the language that appears on the first line of a script? [duplicate]

Bash scripts start with the following line #!/bin/bash # Rest of script below ... In bash the # character is the start of a comment, but #!/bin/bash is definitely not a comment, therefore it isn't ...
3
votes
2answers
2k 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 ...
15
votes
2answers
451 views

Can I list the filesystems a running kernel can support?

I'm trying to detect what filesystems a kernel can support. Ideally in a little list of their names but I'll take anything you've got. Note that I don't mean the current filesystems in use, just ones ...
2
votes
1answer
4k 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 ...
3
votes
0answers
263 views

Enabling GPIO in kernel not working

I have tried to enable the GPIO pins for my system through the Kernel but I am not able to get them to work. When I try this: echo 1 > /sys/class/gpio/export The terminal window just closes. ...
1
vote
2answers
451 views

“kernel driver” in “lspci” output

I often use lspci -v to check the LKM in use for particular hardware device. LKMs are listed as "Kernel modules" and can be seen with lsmod. However, what is a "Kernel driver"? For example here: Is ...
21
votes
3answers
5k views

How much RAM does the kernel use?

This question is motivated by my shock when I discovered that Mac OS X kernel uses 750MB of RAM. I have been using Linux for 20 years, and I always "knew" that the kernel RAM usage is dwarfed by X ...
1
vote
0answers
45 views

Why linux is a monolithic kernel, while you can load/unload modules (e.g. drivers)? [duplicate]

Hybrid- and Microkernels are flexible, in the way one can add any higher-level functionality as a module, is it not the same for linux kernels? Why then linux is called a monolithic?
1
vote
1answer
183 views

Upgrading Red Hat 9 (Shrike) kernel manually

I am following the instructions here on how to manually perform a kernel upgrade in Red Hat. The current Kernel RPM's are: kernel-2.4.20-8 kernel-headers is not installed kernel-ibcs is not ...
4
votes
2answers
128 views

How do you get hardware info and select drivers to be kept in a kernel compiled from source?

I would like to create a minimal kernel for a web server. When you compile a kernel from source how do you get hardware info and then know what drivers need to be kept in the kernel so the rest can ...
2
votes
2answers
111 views

Detecting kernel thread on pre-3.0 kernels

Looking at the proc man page (http://man7.org/linux/man-pages/man5/proc.5.html) it is possible to detect which processes are kernel threads in /proc/<pid>/stat by looking at the flags value ...
4
votes
1answer
87 views

dmesg email digest

I have a remote server which has some issues (Seem hardware related) which means that it logs KVM errors and then sometime later it becomes unresponsive and locked up. There is an often an early ...
1
vote
3answers
729 views

Need small distro without a desktop or windows manager, just to run a single graphical app [duplicate]

I am looking for some help on this from a linux expert. I am very novice when it comes to linux so I am hoping someone can help out. I need a small distro, that is stable. I don't need a full X ...
2
votes
2answers
279 views

Making a bootable pendrive for custom kernel

I read the tutorials to make a mimalistic custom kernel from here and am able to boot it up as explained in the tutorial over a virtual machine using GRUB as the boot loader. I think it would be more ...