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

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Determine whether kernel built-in driver supports a device

I'm trying to find a way to accurately determine whether all the hardware on some system has a valid driver installed either via a kernel module or built-in to the kernel. I'm working with RHEL 5.5 ...
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16 views

Where is the final compiled Linux kernel image located when make vmlinux is ran?

I know this is a rather stupid question, but when I run make vmlinux, where is the final compiled kernel image located? And no, it's not sourcedir/vmlinux (at least for me, neither GRUB nor booting ...
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9 views

What Linux kernel configuration options do I have to set to what to support all the hardware of a 13" MacBook Pro Early 2011?

What Linux kernel configuration options do I have to set to support all the hardware of a 13" MacBook Pro Early 2011? I noticed that with all the distributions I tried, none of the FX keys worked (at ...
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1answer
28 views

Patching the kernel to allow booting without initrd

The first answer of 'Why does Linux use an Initial Ram Disk at boot?' states that the initrd/initial ram filesystem is used to provide drivers to mount the real root filesystem. It also says that it ...
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0answers
25 views

Linux kernel hangs at “Starting kernel …”

I have enabled Secure Boot on an embedded device successfully. The problem is that when I am booting in this mode the process seems to get stuck right after the line: Starting kernel ... once U-boot ...
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2answers
21 views

How to remove /etc/udev/rules.d/70-persistent-net.rules CentOS

I have a server that we are testing a stretched network failover with VMware Recover Point. When the server moves over to the alternate site, the MAC address changes causing my network interface (...
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0answers
15 views

What are heap data structures used for (if anything) in the Linux kernel?

Are heap data structures (ordered binary trees) used anywhere in the Linux kernel? If so, what purpose do they serve in the kernel, and which source files and lines can I see their implementation?
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2answers
53 views

How does Linux handle drivers when changing systems?

This has always made me wonder but how does Linux handle device drivers from system to system, so say you plug it in on computer A and then move to computer B with completely different specs. In ...
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19 views

Edit sysctl.conf file

Using Red Hat Enterprise Linux Server release 5.11 (Tikanga) but I need to change the values for shmmax & shmall. vi /etc/sysctl.conf # Controls the maximum shared segment size, in bytes kernel....
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1answer
4k views

What is equivalent to Mac's purge in Linux? [duplicate]

In Mac I use purge to free up some memory. What is equivalent to it in Linux(Ubuntu Server)? apt-get install purge gave me nothing. If you are no familiar with Mac's purge here is it's man page: ...
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2answers
104 views

Silent disk errors and reliability of Linux swap

My understanding is that hard drives and SSDs implement some basic error correction inside the drive, and most RAID configurations e.g. mdadm will depend on this to decide when a drive has failed to ...
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2answers
226 views

What program(s) is(are) lowering my entropy pool level? [duplicate]

I've made a simple bash script that checks the entropy pool level in /dev/random. I realize that the way I do it, I lower it very slightly at each check (cat /proc/sys/kernel/random/entropy_avail) but ...
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1answer
112 views

md raid5: translate md internal sector numbers to offsets

TL;DR summary: Translate an md sector number into offsets(s) within the /dev/mdX device, and how to investigate it with xfs_db. The sector number is from sh->sector in linux/drivers/md/raid5.c:...
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0answers
23 views

Why does trashing kernel memory result in an instant restart?

Just for fun, I wrote a kernel module that trashes kernel memory starting from 0x7fffffff81000000(for reference, the system call table is at 0x7fffffff81000100) with WP and KASLR disabled. Inserting ...
8
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2answers
2k views

An oom killer thats baffling me

I am not able to understand why would kernel issue this oom killer when I see enough memory is available: Also why are there so many kernel cache pages allocated? I say enough memory is available ...
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0answers
22 views

what is use of put_page and get_page? [closed]

Linux kernel 3.10.12 Q1)I have two APIs of whcih I am not able to understand the usage. They are:- a) get_page b)put_page EDITED I want the usage of the above functios in tcp_sendmsg.There while ...
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1answer
1k views

Intel Skylake + DisplayPort 1.2 MST/Daisy chain on Linux

I am planning to buy hardware for using DisplayPort 1.2's MST feature to daisy chain two monitors in combination with the Intel Core i5 6600 Skylake processor on Ubuntu. Is this supported yet with the ...
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0answers
5 views

RTSX_USB module loaded but SD card not recognized

I am currently running kernel version 4.6.2-1-ARCH and my integrated SD card reader on my Asus UX31A is not functionning. I have tried loading the module as such sudo modprobe rtsx_usb and then ...
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31 views

Fedora Touchpad Stopped Working After Update

So I am on the latest version of Fedora. I have an Acer Aspire E15. I did a dnf update about a week ago (it was probably two weeks out of date at that point) and shutdown. I didn't turn it on again ...
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1answer
1k views

DisplayPort and Intel HD cause GPU hangs

My system has problems with the displayport connection. This is indicated by several problems that, at the first glance, do not have anything in common. The reason why I claim DP for beeing the cause, ...
2
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1answer
196 views

Meaning of an ampersand prefix in a device tree

I am looking at a DTS file which tries to specify different nodes, but interestingly I find a few nodes having different style of nomenclature. / { model = "TI AM335x BeagleBone Black"; ...
2
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1answer
44 views

kernel init without 'root=' parameter

From systemd/fstab-generator.c it follows that systemd treats root= as required kernel parameter, the only configuration source for /sysroot mount. However from kernel/init/main.c and kernel/init/...
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1answer
49 views

Where does a device file come from?

I'm reading through the Linux Kernel Module programming guide and I am a bit onfused about how device drivers work. I tried following along and making a basic device driver, which shows up in /proc/...
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2answers
48 views

When does a new system call get added to Linux?

When exposing kernel functionality, there are several alternatives for kernel developers. They can either create a new system call or expose the functionality through /sys, or /proc entries. Is ...
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2answers
20 views

How can I learn the purpose of the various kernel processes?

(Related: What do the brackets around processes mean?) I'd like to really understand what I'm looking at better. I'd rather not need to dig through actual kernel source code just for a quick ...
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0answers
13 views

Cannot find install-kernel-pkg

I am running Ubuntu 16.04 and am experimenting with building the kernel from source. I am at the step where I want to install the kernel using: new-kernel-pkg --mkinitrd --install --make-default --...
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0answers
8 views

How is the IMQ device positioned in the packet flow of the Linux kernel

I would like to know the exact position of the following device in the packet flow for ingress traffic shaping: IFB: Intermediate Functional Block I would like to better understand how packets are ...
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1answer
45 views

How is the IFB device positioned in the packet flow of the Linux kernel

I would like to know the exact position of the following device in the packet flow for ingress traffic shaping: IFB: Intermediate Functional Block I would like to better understand how packets are ...
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2answers
34 views

How to list the kernel Device Tree

I am using an embedded Arm with a Debian build. How does one list the compiled devices from the device tree? I want to see if a device is already supported. For those reading this, the "Device Tree" ...
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5answers
7k views

How to determine which module taints the kernel?

My kernel keeps panicking when connected to a certain wireless network. I'd like to send a bug report but my kernel is apparently tainted. From /var/log/messages: Apr 17 21:28:22 Eiger kernel: [...
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2answers
837 views

Why should you not edit the .config kernel configuration file?

# Automatically generated file; DO NOT EDIT Is at the header of the kernel configuration file: /usr/src/linux/.config My question is why shouldn't you edit this file? If I know exactly what I need, ...
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33 views

Debian 8 crashes once every few days

I'm running Debian 8 on Linode 32 GB and once every few days the system crashes. This server is being used in productions and I need to find a solution ASAP The only server running on Debian is ...
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0answers
16 views

Mint + Kernel 4.5.4: laptop loses suspend state when unplugged

I'm using Linux Mint 17.3 on a newish Asus laptop with Mate desktop. To get the Nvidia graphics and Elan touchpad both to work, I installed the 4.5.4 Linux kernel. I've pretty much got everything ...
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1answer
27 views

udev rules official docs

I am looking official UDEV rules, documents, I have noticed there are changes in udev rules in RHEL 7. But could not find any documents some thing like 'request for changes'. Please help Thanks,
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2answers
9k views

GRUB2 and kernel vga= parameter

According to the documentation, use of the vga= kernel parameter is deprecated as of GRUB2. The fact that some newer kernels don't seem to support it anymore on certain adapters is of no concern as ...
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0answers
12 views

Build and install kernel module into a defined /lib/module/*kernel directory

I hope someone can help. I had problems with my distribution's kernel, so I built a kernel (same version) to build my modules. My modules would be compatible. However, if I install the modules, the ...
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0answers
26 views

How to enable additional audit logging?

We use Auditd to monitor specific changes on Linux systems. Majority of our rules come from CIS Benchmark guidelines and then few are added specifically to monitor certain command executions. We have ...
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1answer
4k views

Why autoconf.h is not copied automatically to its place?

I'm working on a clean Debian 7.7 install. After the install everything was working fine except the webcam in Iceweasel browser. After reading a lot I found that the best solution is to install ...
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1answer
37 views

How to debug Linux hang?

We are using beagle bone black based custom board, with kernel version 3.12. We are facing system hang during one of the init script,(Which brings up WiFi) this hang happens after random number of ...
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0answers
11 views

Basic mmap implementation [migrated]

I am pretty much new to linux and am writing a custom driver for which I need to use mmap. I have found the sample code in many places as below static int simple_remap_mmap(struct file *filp, struct ...
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1answer
22 views

Can't find CONFIG_PCI on menuconfig

I'm trying to enable the CONFIG_PCI option on a custom kernel I work with, but can't find the option. Searching from the menuconfig screen, I see that CONFIG_PCI should be located under the 'Bus ...
6
votes
2answers
4k 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 suspend/resume,...
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0answers
39 views

Round Robin vs FIFO

recently I had to do some reports about scheduling processes in Linux, and to do so, we were asked to turn off all cpu except 0 to show how processes are running for cpu. But there is one thing which ...
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2answers
86 views

What are the differences between Debian Linux Kernel and Linux-libre?

What are the differences between Debian Linux Kernel and Linux-libre in terms of freedom related issues? I know the Debian Linux Kernel can load non-free modules while in Linux-libre they have been ...
6
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1answer
53 views

Does linux do outer ip fragmentation

I am looking to understand if Linux has the capability to do fragmentation of the outgoing packets at inner IP or outer IP level? I looked the source code in /net/ipv4/files in Linux kernel source, ...
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0answers
25 views

Does linux stops processing related to GUI when we remove the desktop screen from connection from cabinet(CPU box)?

When there is big non interactive software running and if I required more processing power then, after removing the desktop screen does kernel stops processing related to GUI(graphical user interface) ...
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20 views

Does anyone use Netem anymore? Alternatives?

When simulating an IP network you can use Linux built-in network emulator Netem. Together with bridge-utils of course. Simulating packet drop, duplicate packets, jitter et cetera. Is anyone using ...
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1answer
515 views

routing table “220” in Linux kernel 3.2.0-23-generic

I have a Linux machine with kernel 3.2.0-23-generic and it has rule with priority 220 in RPDB which points to routing table named "220": T42:~# ip rule show 0: from all lookup local 220: ...