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

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2
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2answers
128 views

What is the difference between a patch which reverts a commit and a “reversed patch”?

Before May 6th, 2013, the fs/eventpoll.c file in the Linux kernel had the following line #1605: if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) On May 6th, a commit changes this to ...
4
votes
1answer
61 views

What is not accessible from userspace?

I read somewhere (3.1.3) that there's a high ring (supervisor mode) and a low ring (user mode) and that some "things" can be run only from the highest ring. What do they mean by "things"? I'd guess ...
4
votes
1answer
645 views

“Memory corruption detected in low memory” kernel messages?

I have some memory corruption detected in low memory messages. I have read about it here, but I'm afraid I can't really make anything out of the discussion. It does indeed happen when I ...
3
votes
1answer
62 views

How long do dentries stay in the dcache?

On Linux, when I create a new file and open it, an entry about it is created in the dcache's hash table, right? How long does that entry stay there? Does it get removed when nothing is currently using ...
0
votes
2answers
123 views

ck patch for Linux 3.13 [closed]

Does anyone have any news about the -ck patches for Linux 3.13 kernel tree? I've checked here but there's nothing yet...
-3
votes
1answer
39 views

RHEL6: Failed Dependencies when installing a package

Hi I'm getting errors when forcing to install unixODBC package on RHEL 6 here is the following error: http://flic.kr/p/jBEFvP I don't know where to get the following packages that were needed by the ...
0
votes
0answers
79 views

Issue with Hugepage reservation in linux

I have reserved hugepages for my process using below commands: #echo 64 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages #mkdir -p /mnt/huge && mount -t hugetlbfs nodev /mnt/huge ...
0
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0answers
46 views

Recommendation for kernel config UEVENT_HELPER_PATH?

I use Gentoo Linux. Historically the kernel configuration UEVENT_HELPER_PATH to hotplug, then later to udevadm. Mine has been set to /path/to/udevadm, but I've had problems in the past on Gentoo ...
3
votes
1answer
69 views

Embedded Linux: Which machine directory to pick in /arch/arm?

I am just starting out with embedded Android drivers, so any help would be great. I haven't found a lot of resources online. At the moment, I am working through a tutorial on porting a driver, and ...
1
vote
1answer
2k views

What do the kernel parameters acpi_osi=linux and acpi_backlight=vendor do?

I had troubles with the screen brightness control in my laptop and I fixed it by adding the acpi_osi=linux and acpi_backlight=vendorparameters to the filegrub.cfg. I'd like to know what these ...
1
vote
2answers
84 views

why do I need to patch linux kernel to use pandaboard's spi?

I believe this question is a bit more general but here is how it goes : I have read this article about using pandaboard's SPI, especially the part "Configuring and patching the kernel". It says that ...
1
vote
1answer
196 views

Resolving executable user stack trace addresses in ftrace

I'm trying to obtain a user stack trace in ftrace, but for some reason, only my user program cannot resolve the addresses to symbols. First, the OS I'm using is: $ uname -a Linux mypc ...
10
votes
2answers
695 views

Observing a hard-disk write in kernel space (with drivers/modules)

Apologies in advance if this post is a bit dense/messy, but I'm having a hard time formulating it better... Basically, I would like to study what happens upon a hard disk write, and I'd like to know: ...
2
votes
2answers
202 views

In a UID namespace, can I setuid to an unmapped UID?

Suppose I'm user ID 1000. I run a program inside a UID namespace, mapping UID 0 inside the namespace to UID 1000 outside the namespace. The program then attempts to change its own UID to 50, which ...
1
vote
1answer
524 views

How to fix make error “No rule to make target 'menuconfig'” when building a kernel for Beagleboard?

The aim is to build and install the USB Video Class (UVC) module, via make modules_install. I'm trying to configure the kernel via make menuconfig on Angstrom distribution, running on BeagleBoard-xM. ...
0
votes
1answer
117 views

Change the root filesystem on an embedded system

I'm using Buildroot to generate an embedded Linux with a kernel v. 2.6.39, which in the end starts busybox. Everything works fine when building with Initramfs as "rootfs". But Initramfs isn't the best ...
4
votes
1answer
94 views

Why do the data and code segments completely overlap in Linux?

Context: I'm reading "Understanding the Linux kernel, 3d ed", which uses the 2.6.11 kernel. Question: As I understand, the physical address is obtained by translating the linear address, which is ...
8
votes
2answers
336 views

Why does the Linux kernel report “out of disk space” when in reality it is out of i-nodes

A friend of mine who likes programming in the Linux environment, but doesn't know much about the administration of Linux recently ran into a problem where his OS (Ubuntu) was reporting "out of disk ...
2
votes
1answer
129 views

How to build a basic embedded linux on a Qualcomm router?

Not knowing the first thing on how to build a minimal linux system on an embedded device, I'd like to get some pointers in the right direction. Generally speaking, I'd like to know what are the ...
1
vote
1answer
186 views

moving from user mode to kernel mode

I read the following: "All processes begin execution in user mode, and they switch to kernel mode only when obtaining a service provided by the kernel." When it says "obtaining a service ...
0
votes
0answers
168 views

Compiling Linux and Creating Bootable ISO Image

I have already compiled Linux kernel 3.12.6 but did not install it into /boot as I did not want my hard disk to have another OS. I have the compiled bzImage and I don't know how to take that and ...
2
votes
1answer
44 views

Make Install Linux Kernel Location Change

I have already run make to compile the Linux Kernel 3.12.6, but when I run make install, I don't want it to install it in /boot (as I don't want another OS on the hard disk). How can I change it so it ...
0
votes
5answers
261 views

On executable files in Linux [closed]

It is said that in linux, unlike Windows, there's not a clear border between executables and other files. Well, in Windows, I write a C++ program, then it is precompiled, compiled and then linked to ...
0
votes
2answers
327 views

GRE supported in kernel but iproute2 cant create GRE tunnel

Im trying to create IP over GRE tunnel but i get No such device: ip tunnel add gre0 mode gre remote 192.168.152.22 local 192.168.152.21 ttl 255 ioctl: No such device I have compiled GRE support in ...
3
votes
0answers
82 views

LVM RAID 1 for root [closed]

I have LVM RAID 1 (not mdadm RAID 1, but exactly LVM2 RAID 1) for my root partition. I would like to make my system boot without either of the HDDs where the underlying PVs of the root LVM partition ...
1
vote
1answer
61 views

SELinux and Trusted OS - can SELinux be confined to hardware level root?

I am exploring on SE Linux and while doing so i found it as an example of Trusted OS. Is it really an example of Trusted OS stack like TrouSerS ? SELinux as per my understanding modifies the Linux ...
2
votes
1answer
152 views

No usable clock interface found

I just finished installing a paravirtualized archlinux guest on xen. I get the following error when my guest boots: [1.185226] i8042: No controller found [1.1247134] drivers/rtc/hctosys.c: ...
3
votes
1answer
151 views

Is there a command to switch to into an existing namespace?

I am using multiple UTS namespaces, each of them has some servers constantly running. I can get the namespace IDs via readlink /proc/<pid>/ns/uts, now I would like to change into a given ...
0
votes
1answer
268 views

how do I include the qcserial module in the kernel?

I need a kernel compiled, featuring the qcserial module to have support for the Huawei EM 680 model (Gobi 3000). I got kernel 3.11.6 and can find the appropriate source file in ...
0
votes
2answers
87 views

Which runlevel is best for a Linux (Debian) server (DBMS/SCM)?

I currently try to harden the system and the security of a Debian server running a database and a source code management. I just want networking and me (one user) to be able to login. Which runlevel ...
2
votes
0answers
45 views

Detach keyboard from the kernel

I am writing a remote controller app for an octocopter and want to use a keyboard as an input device for this app but I don't want it to have any effect outside this app. Somehow I would like to make ...
6
votes
2answers
124 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 ...
0
votes
1answer
118 views

How to run just linux kernel in vmware?

I am VERY new to Linux and am wondering if you can just boot the Linux kernel by itself or does it absolutely HAVE to be apart of an operating system. My reasoning behind wanting to do this is so that ...
1
vote
0answers
185 views

Computer wont boot with any media after installing wine on Ubuntu 13.10

Yup. I can boot into anything (meaning the os part), like a cd/dvd, a live usb, or the os on the HDD. i can boot into the first screen, which i think is called the grub selection screen and whatever ...
2
votes
0answers
70 views

How can I automatically include all firmware needed by selected Linux kernel modules

I have certain modules which I need compiled into the kernel. Some of these modules require firmware, which used to be automatically included from /usr/src/linux/firmware/. However, no new firmware ...
2
votes
1answer
191 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?
4
votes
2answers
291 views

How does udev get device numbers for the devices it creates?

Spun off from a small exchange in chat. One of the primary advantages of udev is that you don't have to worry about major and minor device number exhaustion anymore. But the devices created by udev ...
1
vote
0answers
144 views

IOMMU causing freezes, disabling causes USB to not work

I'm somewhat new to linux, but I'm running a Xubuntu machine that I recently built. Since I started it up, I had noticed frequent freezes, where both the screen (if plugged in) and any SSH session ...
1
vote
0answers
301 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
63 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.) ...
2
votes
2answers
195 views

How do I apply parameters to specific kernels with GRUB 2?

I have several kernels in /boot. One of them, linux-cc, is for heavy computation, i.e., 100Hz, no preemption, no graphics. I've created a systemd target, named compute.target, that only brings the ...
0
votes
3answers
4k views

CentOS kernel version 2.6.32-431.el6.x86_64 bugs

As far as I updated my centos ver 6.4 to 6.5, the new kernel (2.6.32-431.el6.x86_64) disappointed me! It hangs when I want to plug my external hard to laptop or hangs when I start virtual windows 7 ...
3
votes
2answers
2k views

Installing a cross-toolchain to build ARM binaries on Debian

I tried to install a cross toolchain so I could build Linux kernel on amd64 (Debian testing "jessie") for my ARM system. I have this entry in sources.list: deb http://www.emdebian.org/debian sid main ...
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votes
1answer
54 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 ...
3
votes
1answer
261 views

Asynchronous and parallel algorithms in the Linux kernel

In the Linux kernel configuration, I see these options: config CRYPTO_PCRYPT tristate "Parallel crypto engine" depends on SMP select PADATA select CRYPTO_MANAGER ...
3
votes
1answer
146 views

Find kernel with specific commit

I have recently bought an Acer Aspire E1-572 with NetXtreme BCM57786 Gigabit Ethernet network card. The problem is that currently I cannot see it in ifconfig, but I can see it with lshw: *-network ...
13
votes
3answers
1k views

How to tell Linux Kernel > 3.0 to completely ignore a failing disk?

I am asking this question here in the hope that some Linux-kernel guru can have an answer. This question has been asked on AskUbuntu and on SuperUser without answers: thinking better, it is really ...
1
vote
1answer
101 views

How does the kernel know how much user addressable memory to set aside?

I was reading up on a rather-dated article on the kernel managing memory and had this question on where the Page Table Entries (PTE) would go into. For this example, the author assumes we are on a ...
1
vote
0answers
161 views

May have broken a Debian installation: 'sudo dpkg --configure -a' won't run

I did an apt-get upgrade on my Jessie vps, hosted by DigitalOcean. As many people know, DigitalOcean provides kernels from the host, rather than allowing the VM to boot from its own kernel image. ...
0
votes
1answer
1k 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 ...