Everything about UNIX kernels: development, configuration, compilation, design, etc.
0
votes
1answer
47 views
obtaining kernel build tree
Could anyone explain me what the kernel build tree is?
What files does it include?
How can I obtain it from a cross-compiled kernel source (e.g. 3.4.0)?
6
votes
1answer
122 views
How to blacklist a correct bad RAM sector according to MemTest86+ error imdocation?
MemTest86+ (the version included with Ubuntu 13.04) says
Failing address: 002f796c48 - 759.5 MB
What should I specify in the memmap kernel parameter to bypass this area?
I've tried running ...
3
votes
0answers
37 views
What kernel module function gets called, when I say “cat myfile > /dev/sda” [migrated]
I've skimmed through the Linux Kernel Module Programming guide, but can't figure out:
When I say cat image.iso > /dev/sda, will it cause the write function of file_operations structure to be ...
3
votes
2answers
429 views
Asus X101H - Touchpad not recognized (want to disable while typing)
I have been struggling with this issue for a while and have done an exhaustive search for answers here and elsewhere before posting this question.
On my Asus X101H, the touchpad is not recognized as ...
2
votes
1answer
411 views
Linux disk I/O performance issue — what config options to look at?
We discovered an I/O related performance problem when using the default SLES11 SP2 kernel. Our same application on the same hardware had no issue with (the admittedly ancient SLES9 SP3).
We had a ...
1
vote
2answers
538 views
SCTP support for Linux kernel 3.3.4-5.fc17.x86_64
I'm using Fedora 17 64-bit version, with Linux kernel version 3.3.4-5.fc17.x86_64.
I installed lksctp using yum.
sudo yum install lksctp-tools.x86_64
When I try to run
sctp_status -H 127.0.0.1 ...
1
vote
2answers
43 views
What does longterm mean on kernel.org?
It's fairly easy to understand EOL, mainline and stable kernel, but I'm not sure about longterm here,
What does it mean, or how does it differ from stable kernel?
1
vote
1answer
39 views
compressed and uncompressed kernel on an embedded device
I have been using several different embedded boards that store kernel, init files, filesystem, etc. on partitions of a (micro)SD card. I notice in the example usage or instructions that compressed ...
1
vote
1answer
328 views
Problems when booting with new 3.7.2 kernel on Linux Mint 14
When I updated to the new Kernel 3.7.2, everything goes ok, but when it comes to powering on Linux Mint, it shows me two warnings:
What's wrong and what can I do?
-1
votes
0answers
34 views
create a /proc symlink
I'm trying to build a module using the method shown in this answer.
Basically I need to create a symlink I got it to build, when I try to load it using insmod I get:
-1 invalid module format
and ...
1
vote
1answer
283 views
Linux thin station
I have this pc that I just installed and set it up as Linux thin station. I did all the formatting procedures and copying of image to the HD. When I boot it up, I get these, which I think are driver ...
0
votes
1answer
42 views
building/compiling kernel headers
I am compiling kernel 3.4 and 3.8 for different target devices. I would like to install compat wireless driver which requires kernel header. Could anyone tell me how I can compile/build the kernel ...
6
votes
2answers
679 views
Interruption of system calls when a signal is caught
From reading the man pages on the read() and write() calls it appears that these calls get interrupted by signals regardless of whether they have to block or not.
In particular, assume
a process ...
1
vote
1answer
31 views
Virtual mouse driver, possible X11 problems
I created virtual mouse driver according to Essential Linux Device Drivers book. After I wrote coordinates echo x y > /sys/ ... /coordinates into sysfs node, my program generates event packets ...
4
votes
1answer
181 views
Virtual kernel memory layout: negative values
i'm porting drivers for omap3-board to 3.5 kernel. When I start board I see it:
Memory: 256MB = 256MB total
Memory: 253564k/253564k available, 8580k reserved, 3226106074K highmem
Virtual kernel ...
1
vote
1answer
592 views
Unable to mount root fs after new kernel compile in VMware
So, I'm attempting to compile and use the 3.6.2 kernel on my Debian 6 VM (running under Windows 7 in VMware Workstation 9). I've already had several hick ups, but I am slowly getting through them but ...
3
votes
0answers
56 views
How does kernel know, which pages in the virtual address space correspond to a swapped out physical page frame? [migrated]
Consider the following situation: the kernel has exhausted the physical RAM and needs to swap out a page. It picks least recently used page frame and wants to swap its contents out to the disk and ...
1
vote
1answer
42 views
Problem compiling a driver : “No rule to make target”
First of all I am running a CentOS 6.4 installation.
My computer is a laptop and I am trying to install the drivers for my ethernet card, because this week end I lost my ability to connect to the ...
0
votes
0answers
16 views
Is ZONE_NORMAL mapped on the kernel space only?
In several textbooks I've stumbled upon a strange phrase, that "if the amount of physical RAM available is small, the ZONE_HIGH might not exist at all and all the memory would belong to ZONE_NORMAL".
...
0
votes
1answer
52 views
Enable kernel module for VPN
I'm trying to turn on modules for VPN so I followed this tutorial to compile new ubuntu kernel 3.8.6 .
But the features I've turned on using make menuconfig seem not to be enabled.
(the features I ...
1
vote
1answer
39 views
Excluding kernel modules through /etc/modprobe.d/blacklist.conf does not work
I don't want to load the kernel module nouveau on my debian box at startup, so I put the following in /etc/modprobe.d/blacklist.conf:
blacklist ttm
blacklist drm
blacklist nouveau
I even did a ...
2
votes
1answer
101 views
Would someone please explain lspci -vv output?
I have the following output from running lspci -vv -s 00:00 on my single board computer running linux.
07:05.0 RAID bus controller: Adaptec AAC-RAID (Rocket) (rev 03)
Subsystem: Adaptec ASR-2230S + ...
5
votes
4answers
2k views
Determining cause of Linux kernel panic
I'm running an Ubuntu 12.04 derivative (amd64) and I've been having really strange issues recently. Out of the blue, seemingly, X will freeze completely for a while (1-3 minutes?) and then the system ...
8
votes
2answers
1k views
Heavy write activity on SSD nukes system performance
I've noticed that when I do heavy write applications, the whole system slows down. To test this further I ran this to do a (relatively) low-CPU, high disk activity:
john -incremental > file_on_SSD
...
2
votes
1answer
59 views
What is user address space and what is it's purpose?
I am reading about processes. I came across a topic "How a process is created" wherein I encountered the following :-
The process image as viewed by the kernel runs in its own user address space ...
0
votes
1answer
30 views
Assembly files in obj-m list when building kernel modules
I'm trying to build kexec as a module, but I'm running into a weird problem. My obj-m is:
obj-m += kexec.o machine_kexec.o relocate_kernel.o
When I run the makefile, it complains that there's "no ...
1
vote
1answer
42 views
Can kexec be built to a standalone binary, to be used where kexec was not built into the kernel?
I have remote embedded Linux devices I am trying to update to a new kernel without having to physically access. However, the command line options they boot with make one of the MTDs read only - I ...
1
vote
3answers
54 views
What considerations need to be made when choosing the version of kernel for an embedded device?
I have used buildroot to successfully create a kernel, root file system and cross-compilers to enable me to write application code to run on an embedded device. Currently I have no need to write ...
0
votes
1answer
212 views
“ unsupported for `ljmp' ” error while compiling minimal bootloader and kernel
I'm using gmake to compile this code, but I'm stuck on this error message:
+ as kern/entry.S
kern/entry.S: Assembler messages:
kern/entry.S:55: Error: unsupported for `ljmp'
gmake: * ...
1
vote
1answer
56 views
How to give an ordinary user privileged access to a particular syscall in FreeBSD?
I want to give an ordinary user the ability to fchown() files arbitrarily (as if they were the superuser) on FreeBSD. Generally speaking, is there a right way to change the privilege-checking of a ...
0
votes
1answer
28 views
debian cannot install kernel source
I want to use debian linux for my laptop again. So I took my old debian 6.0 cds and installed it.
From the last time I know, that I have to build the driver for my Atheros AR8151 Gigabit Ethernet ...
0
votes
1answer
54 views
how to gpio interrupt registering/handling and accessing them from user space in linux [closed]
I am newbie for the linux device drivers please guide me how to do this..
suppose I have connected a switch to one of the controller pin and whenever the switched is press the LED connected to other ...
1
vote
1answer
53 views
Only output errors / warnings when compile kernel?
When you compile kernel you normally see lines like
CC XX.o or LD XX
So, can I skip these messages? Only output errors or warnings generated by gcc
18
votes
7answers
9k views
Linux Kernel: Good beginners' tutorial
I'm interested in modifying the kernel internals, applying patches, handling device drivers and modules, for my own personal fun.
Is there a comprehensive resource for kernel hacking, intended for ...
6
votes
1answer
341 views
Linux kernel 2.6 on ARM
I have compiled and installed the 2.6 kernel on an ARM board. I am using the ARM mini2440 board.
I would like to know if there is already a way to access the General Purpose I/O port pins?
Or will ...
7
votes
3answers
391 views
Why does it makes sense to cache swap?
It sounds quite counter-productive to me to cache pages that are swapped out. If you swap pages in, what is the advantage to first cache them in memory, only to have to than move them to the right ...
0
votes
0answers
17 views
Nested Linked List in Kernel [closed]
I have a Linux kernel (3.2) module that requires a nested linked list. The main linked list keep track of target programs. For each target program, we need to keep track of another linked list which ...
5
votes
1answer
246 views
Loading speedstep_centrino kernel module
Because of a noisy fan in my laptop, I need to change CPU frequency and for this task I need to load the appropriate kernel module.
The CPU in my laptop Acer TravelMate 4002WLMi is:
$ cat ...
4
votes
0answers
67 views
Locate occasional CPU kernel hog
I have a 2.6.35 PREEMPT kernel running on moderate-speed ARMv7 processor. About once every 100 - 125s, something causes the kernel to fail to process some audio-related drivers sufficiently quickly to ...
0
votes
0answers
52 views
*ERROR* timed out waiting for panel to power on
I'm using Ubuntu 13.04 on Asus VX6 (1.8GHz Atom - 2 cores, optimus nVidia ION) with Kernel 3.9.0.
When I start my system I get this error:
[ 15.728106] [drm:intel_enable_lvds] *ERROR* timed out ...
3
votes
1answer
51 views
Does the vmlinux header contain the length of the kernel image?
I am trying to disassemble a compound file that consists of several parts, one of which is an uncompressed kernel sandwiched between several other files. I am trying to find the exact length of the ...
0
votes
1answer
64 views
How to troubleshoot high kernel time (high network usage; high interrupts)
I've noticed that I have high kernel time when doing a lot of network traffic in Linux. I also noticed that 45% of my CPU is spent doing interrupts. How can I further troubleshoot this?
0
votes
0answers
41 views
Decreasing mouse sensitivity at kernel level
I have developed a custom-GUI Server, which runs on virtual console of Linux.For mouse-handling purpose, it reads the mouse device file
/dev/input/mice
and retrieves the event data and updates ...
1
vote
2answers
73 views
TLB cache flusing when a page is swapped out
I recently heard that Linux simply flushes the TLB cache when the corresponding data in that physical address is swapped out, resulting in underutilization of the TLB. I don't know whether all OSes do ...
1
vote
1answer
70 views
Booting encrypted root partion fails after system update
I have a problem booting my Debian Linux server. After a system update, GRUB loads the initrd and the system should ask for the password, but it doesn't. Instead, I get dropped to BusyBox. After ...
3
votes
2answers
512 views
Benefiting of sched_autogroup_enabled on the desktop
I am running a 2.6.37 kernel with sched_autogroup_enabled set to 1. I am not certain that I am seeing the benefits of this patch since:
I am launching my applications from the desktop;
applications ...
4
votes
1answer
48 views
Making a recovery partition in embedded Linux
I have an Atmel SAM9X system running Angstrom. I am trying to make a recovery partition so when a user holds a button during boot up the recovery partition boots up.
I have modified the bootstrap so ...
2
votes
1answer
36 views
Sign a module after kernel compilation
I've built a kernel in tmpfs, then I rebooted.
Now I see a message when I compile the 3rd party module,
NO SIGN [M] XXXX.ko
How can I get it signed? The key pair generated during rpmbuild is lost ...
-4
votes
2answers
115 views
Why is the UNIX kernel so crucial? [closed]
More specifically, how is the UNIX kernel treated differently from other parts of the Operating System?
0
votes
1answer
30 views
Understanding a XINU system call - getstk.c [closed]
I am having trouble conceptually understanding what is going on towards the end of this system call, and why. I understand the getstk.c method returns the highest memory address of available space, ...
