In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources (the communication between hardware and software ...

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5
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2answers
2k views

Removing stubborn modules

I'm trying to programatically stomp on bluetooth on RHEL5. I've got the service stopped -- no problem. Also no problem on rpm -e for the associated bluetooth packages, bluez-*. ps -aef | grep -v ...
1
vote
0answers
15 views

detecting whether GPUs are accessible before running nvidia-smi during boot to create dev files

In the past, I've successfully configured Ubuntu systems containing NVIDIA GPUs to launch nvidia-smi in the background from within /etc/rc.local during the system boot to create the requisite ...
-3
votes
0answers
12 views

Some users get kern version message by visit website [on hold]

For some users my website seems not to load correctly. For myself and many others the website loads but for some they get a server message such as: 'kern version = ....' while they access the website. ...
-1
votes
0answers
43 views

How can we disable Windows PatchGuard?

I'm trying to disable Kernel Patch Protection to be able to run apps like EasyHook and etc. What are some trustable solutions to disable PatchGuard? (Had found a thread but am not too sure about ...
-1
votes
0answers
7 views

How to get the Adaptec 1200A to work under Linux at UDMA/100 (instead of 66) [migrated]

A while ago, I got myself a used Adaptec 1200A controller card to keep my onboard slots free for easier connect/disconnect of drives and now I am wondering why this card will only operate at UDMA 66. ...
0
votes
0answers
11 views

Run compiled kernel with mcp251.x support

I have jetson tk1 board with ubuntu 14.04 pre-installed. I want to add mcp2515 functionality to it. How can I get it running? First of all, I set up the support of can bus in kernel and make and ...
0
votes
1answer
39 views

SSD caching using bcache or dm-cache on kernel 2.6.32-042stab104.1

I'm looking to use bcache or dm-cache with the latest OpenVZ kernel (2.6.32-042stab104.1) on CentOS 6. Unfortunately, dm-cache and bcache are part of kernel 3.10, but I know the OpenVZ kernel has a ...
0
votes
1answer
513 views

What kernel module to compile for getting QOS service on Linux

We are developing on Linux system whose kernel had been compiled without QOS service years ago. Currently we want the QOS service back and plan to compile only the QOS-related kernel modules and ...
3
votes
4answers
2k views

GRUB “Some modules may be missing from core image” Error

one HDD crashed from my RAID and I added a new HDD. Now I wanted to install GRUB to the new HDD: with grub-install /dev/sdb. I get these errors: Installing for i386-pc platform. grub-install: ...
23
votes
6answers
23k views

How do I list loaded Linux module parameter values?

Is there a standard way to list the parameter values of a loaded Linux module? I'm essentially probing for another answer to this Linux kernel module parameters question, because the module I'm ...
0
votes
3answers
42 views

Kernel Processes Periodically Eating CPU During High Load

I run a production web server with 24 cores in which the work is both CPU and I/O intensive, but mostly CPU. My scripts delay execution when total CPU load is ~85% or higher in order to keep the load ...
0
votes
0answers
7 views

Compiling a loadable kernel module(Debian/Ubuntu) [migrated]

This question is a follow up of this one. I am trying to compile the ELF loader as an individual LKM and use it as a standalone application(replacing the original module within the base kernel sounds ...
0
votes
0answers
18 views

Broadcast ARP weirdness

we a running a router on a custom Linux box. Kernel is 3.14.14. What happens is that when you arping the router in broadcast only mode is the router has a verey slow response time: # arping -b -c ...
0
votes
1answer
32 views

Compiling an individual kernel module (Debian/Ubuntu)

I need to modify the ELF loader's kernel implementation of an Ubuntu 14.04 distribution. Having downloaded the sources using: sudo apt-get source linux-image-$(uname -r) I ran the configuration ...
1
vote
1answer
28 views

how to debug futex congestion in system

I have perl multithreaded script ("assp antispam proxy") that uses multiple perl libraries. On one of my servers after about 2 hours script starts to make huge number of futexed which consumes a lot ...
1
vote
2answers
2k views

CentOS 6 Xen guest fails to boot after 'yum update'. Kernel?

I Seem to be having an issue with a Xen guest not booting after a yum update. DomU Configuration: #kernel = '/boot/solus-vmlinuz' #ramdisk = '/boot/solus-initrd.img' bootloader = ...
0
votes
1answer
43 views

grubby fatal error: unable to find a suitable template

I'm trying to fix my system after moving it from one server to another. It works perfectly with kernel booted via network, but not from the disk. Reinstalling stock CentOS 6.6 kernel shows this ...
8
votes
2answers
543 views

Why “lsmod | wc -l” not equal “ls /sys/module | wc -l”

Why do these two commands return different results? lsmod | wc -l 100 ls /sys/module | wc -l 138
0
votes
0answers
18 views

Network Interfaces Cards and rx_short_length_errors and Linux Kernel

My machine (Linux OS) is counting packets with wrong length, it is a huge environment (GW's, Routers, Switches...) , so I would like to understand how NIC's behaving with these packets. -Does NIC's ...
0
votes
2answers
56 views

Can a Linux Kernel be shared between two operating systems?

Quite simple question. I am working on a project to have multiple operating systems (all linux) on the same machine using btrfs subvolumes so that the user can boot to the environment they are ...
0
votes
0answers
40 views

Cannot start OpenVZ container

When I try to start container I got Starting container... Opening delta /var/lib/vz/private/100/root.hdd/root.hdd Adding delta dev=/dev/ploop15117 img=/var/lib/vz/private/100/root.hdd/root.hdd (rw) ...
10
votes
2answers
9k views

How do ulimit -n and /proc/sys/fs/file-max differ?

I notice that on a new CentOS image that I just booted up off of EC2 that the ulimit default is 1024 open files, but /proc/sys/fs/file-max is set at 761,408 and I'm wondering how these two limits work ...
1
vote
0answers
19 views

insert module to kernel [migrated]

I installed latest version of IPCOP, I've the correct module of my wireless card (htc_9271.fw): put it to /lib/firmware/ there is not any insmod/rmmod but only modprobe: modprobe htc_9271 FATAL: ...
1
vote
0answers
108 views

Linux kernel module “Unknown parameter” stops module from loading. How to load module anyway?

The following is happening on a Ubuntu 10.04 system I'm working on: The kernel is shipped with e1000 driver module version 7.3.21-k5-NAPI. This version of the module is causing problems. To fix, the ...
2
votes
0answers
755 views

OpenVPN ERROR: could not insert 'tun': Unknown symbol in module, or unknown parameter (see dmesg)

I'm trying to configure OpenVPN on my Debian 7 VPN but I'm getting the following error ERROR: could not insert 'tun': Unknown symbol in module, or unknown parameter (see dmesg) I tried the ...
1
vote
1answer
2k views

File-descriptors setting on /etc/sysctl.conf

I have recently learnt that to be able to increase the amount of virtualhosts that we can serve via Apache depends on file-descriptors. they say the value should be added to /etc/sysctl.conf as ...
-2
votes
0answers
25 views

Getting segmentation fault when giving input to structure members on run time [migrated]

I have written a small code to fetch info of 'n' number of students. But after running the program, I'm getting a segfault. Please find the code below. struct students { char name[20]; int ...
2
votes
1answer
43 views

Use VPS provider's kernel or maintain my own?

I've got a Debian Wheezy VM on Linode and they run it with their own kernel. As a reputable company, I'm sure they're quick to apply security patches, and all I need to do is reboot to get the new ...
0
votes
1answer
1k views

Kernel parameters mem and dom0_mem in XenServer 6.1

We are running XenServer 6.1 in production, and recently had OOM-killer fire and eventually take down one of our blades. I noticed that in the kernel logs from the oom-killer instance that it seemed ...
1
vote
0answers
67 views

Upgrading CentOS from 6 to 7 has broken my boot sequence

I ran the upgrade assistant provided by CentOS for upgrading from CentOS 6 to 7. The upgrade appeared to have been a success, however my system now hangs when trying to boot up. (Keep in mind I have ...
0
votes
1answer
56 views

New linux with old kernel in chroot [closed]

I have access to enterprise level server, but it have kernel version Description: Red Hat Enterprise Linux Server release 6.4 (Santiago) Release: 6.4 Codename: Santiago ...
0
votes
1answer
32 views

Enable IP forwarding inside an OpenVZ container but disable it on host

Is it possible to enable IP forwarding inside an OpenVZ container but keep it disabled in host system? I understand that OpenVZ containers and host share kernels, but I can use sysctl to set ...
0
votes
0answers
38 views

How to find what is causing a Kernel EventTracing error in the Event Log?

I am troubleshooting a Kernel EventTracing: "session failed to start with the following error: 0xc0000011" that pops up too many times in my event log. Every solutions I found in google were very ...
2
votes
0answers
62 views

BUG message on xenserver 6.5 - bad memory?

Several times a day I receive the following error in /var/log/messages. The server hangs and requires a reboot to respond again: Feb 1 13:44:54 xenserver-abfuqvrs kernel: [35023.166776] BUG: unable ...
-1
votes
2answers
237 views

Can you use CGroups inside an OpenVZ Container?

just a quick question, which i have had trouble finding the answer to: The OpenVZ Authors have been contributing a large amount of code to the linux kernel, in order to get virtualization features ...
15
votes
2answers
266 views

Does the “bs” option in “dd” really improve the speed?

Every now and then, I'm told that to increase the speed of a "dd" I should carefully choose a proper "block size". Even here, on ServerFault, someone else wrote that "...the optimum block size is ...
0
votes
1answer
26 views

What does the tcp_fastretrans_alert error mean?

I found this error a couple of times in /var/log/messages after experiencing some odd TCP behavior: For some reason, if I connect to for example SSH for the first time in say an hour, the connection ...
0
votes
1answer
47 views

Which is the physical device behind the logical /dev/___ device

From time to time I get myself dealing with this same problem: from a linux logical block device (something below /dev/), I need to find the actual hardware behind it (something probably being listed ...
1
vote
0answers
31 views

make linux kernel read swap back into memory [closed]

Occasionally, I run a script that uses the majority of the 16GB of physical memory on my workstation. The kernel then swaps out the rest to swap partitions on multiple disks. After the script is ...
0
votes
1answer
54 views

enabling modules for a kernel

I have a KVM/XEN VPS and would like to enable the following modules: ipt_LOG ipt_multiport ipt_state ipt_limit ipt_recent ipt_owner iptable_nat tun/tap iptable_nat ipt_MASQUERADE ipt_POSTROUTING PPTP ...
1
vote
1answer
107 views

Not seeing kernel messages in syslog

I'm trying to track down a process that kills my mysql server on my CentOS box. I have the following setting in /etc/syslog.conf: *.*;mail.none;authpriv.none;cron.none /var/log/messages I ...
3
votes
1answer
730 views

VMWare ESXi error upon boot “Relocating modules and starting up the kernel”

Coming back from a 4-day weekend, I noticed the A/C had been turned off for the duration of the long weekend and the heat was around 80-82 degrees. The HP ProLiant DL185G5 was running but the system ...
1
vote
2answers
3k views

Server won't boot, kernel panic - not syncing

After a reboot of a CentOS 6.2 server we are getting a kernel panic with the following error: Kernel panic - not syncing: Attempted to kill init! Panic occurred, switching back to text console ...
1
vote
1answer
44 views

Influence of kernel code execution to Load average in top?

I'm trying to tests the amount of CPU that iptables use for NAT. Perhaps it will be more accurate to say "the amount of CPU that the netfilter kernel module" uses. The approach i took was to try and ...
1
vote
3answers
1k views

Error installing new OpenVZ kernel

Seem to have an error when updating the kernel on a OpenVZ server when running "yum update" im getting the below Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: ...
4
votes
3answers
172 views

Modifying kernel cmdline in Ubuntu

I have a number of systems on which I need to modify the kernel cmdline, adding a few options. At the moment I do it using the following procedure: Open /etc/default/grub Modify ...
3
votes
1answer
50 views

How to keep specific old kernels around after a yum update

I know that in CentOS 6.x, you can put the following line in /etc/yum.conf which tells yum to keep the last N kernels (by default this is set to five): installonly_limit=5 However, there are cases ...
1
vote
1answer
29 views

Kernel dependency error on Ubuntu 12 server

I was doing my quarterly updates of an Ubuntu 12 server. After an apt-get update succeeded I'm getting this error running apt-get anything. Depends: linux-image-server (= 3.2.0.72.86) but it is not ...
0
votes
0answers
30 views

How does a kernel patch propagate into distribution updates?

I have been affected by, and helped to debug, a kernel bug. A patch has been created by the maintainer of the module, and submitted. I am interested to know how the patch propagates through to binary ...
4
votes
1answer
349 views

Linux cgroups cpuset w/ subs causes cgconfig not to start

I am having a problem trying to separate 2 groups using cpuset subsystem. This works fine, however if i go to add a subgroup to that group (in this case -- user1), cgconfig will fail to start with ...