0
votes
0answers
23 views

Noob Kernel Image Question

I'm playing about with CM-FX6 , an iMX6 based SOC. The chip comes with the following: http://www.compulab.co.il/workspace/mediawiki/index.php5/CM-FX6:_Linux:_Kernel **images** uImage-cm-fx6 - ready ...
2
votes
0answers
23 views

Why is there no rootfs file system present on my system?

The linux kernel documentation claims: Rootfs is a special instance of ramfs (or tmpfs, if that's enabled), which is always present in 2.6 systems. You can't unmount rootfs … On all linux ...
1
vote
1answer
25 views

Booting into a kernel image

I have a recently-compiled Linux kernel image (vmlinuz file) and I want to boot into it. I am aware that this won't give me a familiar Linux system, but I am hoping to be able to at least run some ...
6
votes
1answer
8 views

Linux kernel 3.10.0-123.4.2 processes [flush] aren't present

I am using CentOS 7 with "3.10.0-123.4.2.el7.x86_64" version, but I don't know why the kernel threads named flush aren't present in this kernel version. I tried to look in the kernel change log, but ...
1
vote
0answers
23 views

“disagrees about version” message

I get a message "disagrees about version" on boot time, after compiling kernel and modules with KGDB. Why should this happen ? Is there any problem with KGDB ? This is the relevant log at boot: ...
1
vote
1answer
31 views

/proc/config.gz is of 0 bytes

I have an Android TV stck I compiled Linux for IT from https://github.com/Galland/rk3x_kernel_3.0.36 But when I booted that Image I found /proc/config.gz is of 0 bytes can some please explain how ...
0
votes
1answer
30 views

install kernel headers without overwriting old headers

I've built a newer (3.16-rc2) kernel which is running fine. My userspace program needs to link against the newer headers as it uses some new definitions in fcntrl.h etc. My question is how do I ...
2
votes
0answers
19 views

Linux kernel module to read out GPS device via USB [migrated]

I'm writing a Linux kernel module to read out a GPS device (a u-blox NEO-7) via USB by using the book Linux Device Drivers. I already can probe and read out data from the device successfully. But, ...
0
votes
0answers
7 views

Communication between two kernel drivers [migrated]

I have custom embedded hardware i'm working on which runs linux. I've implemented a spi kernel driver to handle spi access to a eeprom which is exposed to userspace. Now i have another kernel driver ...
1
vote
1answer
31 views

Built new kernel, LVM won't mount from initrd

I need to upgrade my kernel on a RHEL 5 system to build with some experimental drivers. I have configured the kernel with module loading for LVM (dm_* modules). Once the initrd runs the /init ...
3
votes
0answers
42 views

Output shutdown messages to multiple consoles

I have configured my system to direct console output on boot to serial and vga using kernel parameters. Serial is the last argument in the kernel parameters and will be the default used for ...
0
votes
0answers
22 views

SLES 10 SP4 - how to get specific kernel source?

I want to look at the kernel source for some specific kernel versions on SLES 10 SP4. I don't want to see just the Linux kernel source, but the one SLES is actually running. Suppose I wanted to get ...
5
votes
0answers
55 views

Linux kernel dropping custom keyboard scan codes

I have a vintage IBM 122 key model M keyboard that I am adapting for use on a modern computer. I am using a Teensy 2.0 to do the encoding and to handle the USB side of things. I borrowed the firmware ...
2
votes
3answers
51 views

Un-mount active partition

Is it possible to umount the partition, whose files/directories are in use? The underlying files and directories are in memory so un-mounting the partition is technically safe (I guess). But umount ...
1
vote
3answers
54 views

Could it cause any problem if I not reboot after a kernel upgrade?

I know there are solution for not rebooting after kernel update: https://en.wikipedia.org/wiki/Ksplice But If Ksplice isn't installed, and the user doesn't reboots it's notebook after even several ...
1
vote
1answer
30 views

How to modify huge patch file properly?

I have this patch. I want to disable patching of Makefile and drivers/video/logo/logo_linux. What is best way of doing this? Do I edit it, and delete that specific entries? If so, is there a tool ...
1
vote
1answer
150 views

Debian + Linux kernel 3.12.22: “Kernel module loader” option is not available

The Debian guide for compiling a kernel says: Do not forget to select “Kernel module loader” in “Loadable module support” (it is not selected by default). If not included, your Debian installation ...
0
votes
1answer
48 views

Debian: GPG cannot fetch Linux Kernel key

I am in the process of recompiling the kernel on Debian. Following the instructions on kernel.org, the first step is to verify the signature. But GPG complains that it cannot find the public key: # ...
2
votes
1answer
42 views

Automatized kernel upgrade

I am writing a BASH script that automatically configures, builds and installs the most recent kernel image. The generated kernel should include the grsecurity patchset. It would use the previous ...
2
votes
0answers
59 views

kernel build: why does 'make install' complain about missing modules?

I'm building a 3.2.x kernel on a RedHat Enterpise system. During 'make install' it takes a very long time and is complaining : ERROR: modinfo: could not find module xxx I assume its probing ...
2
votes
2answers
473 views

Linux freezing guess: keyboard & mouse (Archlinux and Ubuntu)

Linux on my PC is freezing a few seconds after startup. I am unable to use the mouse / keyboard. Neither Ubuntu nor Arch do anything after a few seconds. Windows has been running fine for years now. ...
16
votes
5answers
955 views

Where does uname get its information from?

Where does uname really get its information from? I figure this is something that should be straightforward. Unfortunately, I can't find any header containing just that information. Say someone ...
1
vote
0answers
42 views

Do kernel threads seem to interfere with full tickless mode?

I'm trying to disable local timer interrupts for low latency. I have full tickless mode enabled in the kernel config and I have the boot parameter nohz_full set for the cores in question. However ...
0
votes
1answer
137 views

Kernel 3.14.1 compilation errors

I installed the kernel 3.14.1 and there seem to be no issues. uname -r 3.14.1-031401-generic However, when I try to go to the folder and try to do a make it fails. I see that multiple files are ...
3
votes
1answer
80 views

When is swap triggered or how to calculate swap_tendency?

I'm trying to use Redis for production services and trying to avoiding swapping, which is bad for performance. I had learn that swap is triggered by swap_tendency which is depending on ...
4
votes
1answer
62 views

What causes /proc/<pid>/* resources to become owned by root, despite the procs being launched as a normal user?

I've noticed that some procs, such as bash, have their entire /proc/<pid>/ resources readable by the user who created that proc. However other procs, such as chrome or gnome-keyring-daemon, have ...
2
votes
0answers
19 views

Intel Xeon stuck at 800mhz CPU Freq on RHEL 6.5 [duplicate]

Currently running into a headache trying to figure out why my CPU speed is stuck as such a low frequency. After doing some research, I found that cpuspeedutil does actually control the state of the ...
1
vote
2answers
54 views

How to find out the bad block table offset and how to change it in u-Boot

I am facing a similar problem as this: Kernel does not recognize nand bad blocks marked by u-boot I'm using a friendlyARM micro2440 board that contains the s3c2440 ARM processor. u-Boot has found ...
0
votes
2answers
107 views

Porting jvm into the kernel space?

Currently I am playing with the idea of a jvm running in the kernel space, as a (maybe linux) kernel module. I see a lot of advantage of the idea. Of course the biggest advantage of a such system ...
1
vote
0answers
34 views

Get log from kernel while loading

There is a arm/omap2-based device without ethernet, UART ports. It has usb connection with host, numeric keyaboard, LCD display. There is working U-Boot and kernel images for this. I'm trying to ...
2
votes
0answers
58 views

How to check and set “rhash_entries” parameter?

I'm reading this article, and it says: rhash_entries is the size of the hash table. If you don't specify it on the kernel command line, it is computed dynamically based on the memory available on ...
0
votes
0answers
35 views

Black screen when kernel boots with vga= parameter

Recently recompiled kernel refuses to do output on the screen if vga parameter was in the list. Without it kernel boots properly as usual, however, before that it changed resolution and RC log ...
1
vote
1answer
47 views

How to undo kernel settings?

While trying to read some kernel parameters, I think I have mistakenly set some instead: # sysctl --system -r ^net.*tcp * Applying /usr/lib/sysctl.d/00-system.conf ... * Applying ...
6
votes
1answer
181 views

Can you explain the entropy estimate used in random.c

/dev/random uses the timings of kernel interupts to add to the entropy pool. The amount of entropy in the pool is tracked in a variable named entropy_count. Here is the relevant snippet of code from ...
0
votes
1answer
30 views

Is there any alternative to genext2fs in RHEL?

I am tryting to make initrd file system following [this tutorial][1] My host system is RHEL 6 64 bit. I am unable to get the required command: genext2fs No rpm is available for it, neither ...
2
votes
1answer
470 views

What would happen if the amount of free memory (vm.min_free_kbytes) was too low?

I came across the following parameter in kernel settings (in sysctl): vm.min_free_kbytes This is the amount of free memory (RAM) that's always free no matter what. In my case, I have only 1 GiB of ...
2
votes
3answers
168 views

how is page size determined in virtual address space?

Linux uses a virtual memory system where all of the addresses are virtual addresses and not physical addresses. These virtual addresses are converted into physical addresses by the processor. To ...
3
votes
1answer
42 views

filesystem that works under qemu and I can mount on my host

I'm using qemu for different kind of tasks, I would like to pick a filesystem that is both qemu-compatible and easy to mount under my host. I already discarded both qcow and qcow2 because apparently ...
1
vote
1answer
42 views

Getty instances in init process

Init typically will start multiple instances of "getty" which waits for console logins which spawn one's user shell process. Upon shutdown, init controls the sequence and processes for shutdown. The ...
1
vote
0answers
96 views

Some questions compiling linux kernel with make-kpkg

I'm doing my first steps compiling the linux kernel and adding a new system call. I've managed to do it, but I still have some questions. For this task, I has set up a Virtual Machine guesting debian ...
1
vote
1answer
29 views

Build kernel with multi_v7_defconfig setting

What is multi_v7_defconfig used for and how do I build the Linux kernel with this? I think I can write this into config file as: CONFIG_multi_v7_defconfig=y Please correct me if I'm wrong.
0
votes
1answer
135 views

set permission 0666 on /dev files at boot time

I have to load a few additionals modules. One of them generates /dev/knem file. I have to set the permission to 0666, so a basic chmod 0666 /dev/knem works, but I would like to assign it directly at ...
4
votes
1answer
358 views

kernel: disabling /dev/kmem and /dev/mem

I understand that /dev/kmem and /dev/mem provide access to the memory (i.e. raw RAM) of the system. I am also aware, that /dev/kmem can be completely disabled in kernel and that access can be ...
0
votes
0answers
40 views

Can I use lldb to remotely debug the Linux kernel?

With GDB, I can remotely debug the Linux kernel. lldb, which promises to completely replace GDB, should be able to remotely debug the Linux kernel too. However, I cannot find any tutorial about this ...
0
votes
1answer
338 views

modpost.h:12:23: fatal error: elfconfig.h: No such file or directory

I am running Ubuntu: #lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04.4 LTS Release: 12.04 Codename: precise Kernel info: 3.8.0-38-generic ...
1
vote
2answers
152 views

FATAL: Module hello.ko not found

I'm using CentOS-6.5 and default kernel is 2.6.32-431.11.2.el6.x86_64. I downloaded 2.6.32 and built that kernel (under /lib/modules/2.6.32). I wrote a module for simple hello world program. This ...
1
vote
2answers
58 views

Block physical console access

I'd like to block physical console access to my linux. I'd like to find, which module is responsible for keyboard input (ps/2, usb, ...) and vga output (only physical), so I can remove them from my ...
0
votes
1answer
71 views

Do I have to compile the kernel every time, even for a small change?

In my project I configure the kernel (2.6.32) in block/ioctl.c. We all know that kernel compiling and building takes few hours. Even for a small change, I'm compiling from scratch. So is there any way ...
0
votes
0answers
17 views

how get net switch info in soc?

I have a router device. cpu is mtk7620n. mtk7620n have a switch. How can i get information of the switch . swconfig show nothing. i think the switch have no driver. Anybody give me some ...
2
votes
2answers
178 views

Are system calls the only way to interact with the Linux kernel from user land?

Are there any other interfaces, e.g. the /proc filesystem?