Everything about UNIX kernels: development, configuration, compilation, design, etc.
4
votes
1answer
274 views
Is it safe to use customized CFLAGS for linux kernel, e.g mmx sse instructions
Is it safe to use customized CFLAGS while compiling linux kernel, e.g enable SSE, MMX instructions, is that a problem ?
3
votes
2answers
626 views
Can I detect if my custom made kernel was built with module support?
I have been provided with a vendor supplied minimal linux installation. From an answer to a previous question I discovered that it is possible to build a kernel with or without module support. I have ...
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 ...
2
votes
0answers
63 views
How to deal with closed source modules when configuring a new kernel build
I found this command very useful:
make localmodconfig
However, having some closed source drivers/modules ends up being a problem because this command can't find an appropriate way of including the ...
0
votes
2answers
207 views
yum is asking the kernel version which is already there
I have a server with centos 5.3 x86_64 on it. I am trying to install some asterisk modules on this server using yum. So yum asked me to upgrade my kernel to "kernel-2.6.18-308.11.1.el5"
Then i have ...
2
votes
0answers
48 views
What are the differences between the current Linux kernel and the Unix SVR4 kernel in terms of device drivers+i/o and virtual files systems?
Yes I realize that Linux supports many more file systems and recognizes more devices than Unix SVR4. I'm interested in what the differences are in the abstraction on top of an actual file system, or ...
2
votes
2answers
184 views
Do Solaris 10 and 11 still use slab allocation for their kernel memory allocator
If not, what do they use. Please provide a source.
2
votes
0answers
78 views
How to find where driver.mod.c links to?
I'm trying to port the webcam composite gadget from kernel 2.6.37 to 2.6.32. I don't have a choice on this since I depend on other drivers and a SDK which only compile for this version.
My train of ...
5
votes
2answers
425 views
Does Linux kernel 3.x use the CFS process scheduler?
Does the latest version of the Linux kernel (3.x) still use the Completely Fair Scheduler (CFS) for process scheduling which was introduced in 2.6.x ?
If it doesn't, which one does it use, and how ...
0
votes
1answer
432 views
How to calculate TCP checksum [closed]
I am using netfilter hook POST_ROUTING in a kernel module to capture packets.
I am doing NOTHING to the packets, not a single change.
I simply check if it's a TCP and then re-calculate the ...
4
votes
1answer
479 views
How can I use netconsole to help solve a kernel panic?
When I try to use a raid as root, my system panics.
I want to read the kernel output right before the panic, but can't scroll up.
After Googling a bit, I wanted to try netconsole.
but I get no output ...
9
votes
2answers
275 views
How am I supposed to keep up with kernels as a developer?
I'm developing for a specific TI ARM processor with custom drivers that made it to the kernel. I'm trying to migrate from 2.6.32 to 2.6.37, but the structure changed so much I will have weeks of work ...
2
votes
1answer
316 views
High memory (user space) and highmem (kernel space)
Each process has 2 memory area: User space (high memory) and kernel space (low memmory). In the kernel space, are the first 896 MB used for mapping kernel code (not fully 1 GB)? This means, when a ...
1
vote
0answers
241 views
Can I apply real time Linux kernel patch on Android kernel?
I would like to apply real time patch on the Android kernel (given I've found Kernel patch for corresponding Kernel version).
Is it possible or should I create a patch specifically for the purpose of ...
4
votes
1answer
215 views
When should I keep debugging symbols in kernel modules?
When installing kernel modules, I have the option to strip out debugging symbols using INSTALL_MOD_STRIP=1. This saves significant disk space.
Does it also save memory? Why should one keep the ...
3
votes
2answers
648 views
Booting a newly compiled linux kernel
I have started reading the book Essential Linux Device Drivers. I am following the process for compiling and booting into a new kernel. However I am unable to boot into the newly compiled kernel - I ...
2
votes
1answer
172 views
Automatically update a Debian system
I want to automatically update a Debian system (actually Debian Wheezy on Raspberry Pi, though that shouldn't make much a difference). I've already seen that there is cron-apt, probably a good choice, ...
4
votes
1answer
1k views
How do I convert a kernel .config file from 32-bit to 64-bit?
At this page you can download a configuration file that lets you target a particular notebook architecture during the compilation of a new 32-bit Linux kernel.
I need a 64 bit version.
What do I ...
0
votes
1answer
758 views
How can I generate /proc/vmcore?
I want to practice with makedumpfile. However, it needs /proc/vmcore which is the memory image of the currently running kernel.
Also, reading the man page of makedumpfile, we also need 2 kernels: ...
1
vote
1answer
98 views
Choose kernel for specific hardware
I have old system with an AMD Athlon 1,2 GHz processor and [SiS] 65x/M650/740 graphics (output from lspci).
Recently I discovered on a german ubuntu page that since version 10.10 some older ...
1
vote
1answer
242 views
Is Native Language Support (NLS) kernel support still necessary?
Does ext4 / cifs system need kernel NLS support ? I'm not sure if it's being handled by user-space program (decoding / encoding) ?
1
vote
0answers
279 views
Memory mapping of the Linux kernel : how extended (4MB) and regular (4KB) paging coexist?
On x86 architecture, "Extended paging" allows page frames (physical memory) to be 4 MB instead of 4 KB.
The book "Understanding the Linux Kernel, 3rd" at chapter 2 "Memory Addressing", sub-chapter ...
4
votes
2answers
624 views
How to know if a network interface is tap, tun, bridge or physical?
As far as i know, there are 4 main types of network interfaces in linux: tun, tap, bridge and physical.
When i'm doing sys admin on machines running KVM, i usually come accross tap, bridge and ...
1
vote
1answer
147 views
Edit the .config file when en/disabling a particular option like CONFIG_CPU_FREQ?
From here: http://www.xenomai.org/index.php/FAQs#Which_kernel_settings_should_be_avoided.3F
Which kernel settings should be avoided?
Note that Xenomai will warn you about known invalid ...
4
votes
0answers
661 views
WARNING: modpost: Found 10 section mismatch(es)
Is this error message something that I should be worried about?
linux-y3pi:/usr/src/linux-2.6.38.8 # make modules
scripts/kconfig/conf --silentoldconfig Kconfig
CHK include/linux/version.h
...
4
votes
1answer
905 views
How to know whether the Linux driver for the real-time network device was built into the kernel?
From here: http://www.xenomai.org/index.php/RTnet:Installation_%26_Testing#Debugging_RTnet
The Linux driver for the real-time network device was built into the kernel and blocks the hardware.
...
2
votes
2answers
506 views
Where can I find the Linux driver for headphones in the kernel tree?
I have headphones with three buttons on them which allow me to control my music player with my phone. I want to write a driver for my headphones to make it control my music player on my pc (Ubuntu ...
1
vote
1answer
217 views
install 2.6.32.59 on squeeze
I'm suffering from a kernel bug in a production environment. The problem isn't causing a complete outage, but it's degrading service.
These are soft lockups.
I'd like to try a newer kernel, ...
2
votes
1answer
282 views
Is it necessary to enable CONFIG_USB_OHCI_HCD , when there's only USB 2.0 ports
Is it necessary to enable CONFIG_USB_OHCI_HCD on a system that has USB 2.0 port only ?
I'm not sure those devices present , e.g bluetooth , camera use that driver ?
Bus 001 Device 001: ID 1d6b:0002 ...
1
vote
1answer
144 views
Where is CONFIG_APM in kernel - 2.6.38.8
From here: http://www.xenomai.org/documentation/xenomai-2.6/TROUBLESHOOTING
Q: Which CONFIG_* items are latency killers, and should be avoided ?
...
APM: The APM model assigns power management ...
1
vote
1answer
84 views
ACPI (Advanced Configuration And Power Configuration) not present on 2.6.38.8?
I need to disable some parts in ACPI, but it is
simply not present in kernel 2.6.38.8 (downloaded
as a tar from net)?
I can see the option in kernel 2.6.34-12 (default
on OpenSuse 11.3), but not in ...
0
votes
1answer
251 views
buildroot/busybox: launch bootchartd on startup
I built a custom linux image using buildroot and busybox. To speed up the boot process I'd like to use bootchartd (built-in version of busybox) to profile the process. However bootchartd is not ...
1
vote
1answer
121 views
how to enable sound support in linux kernel without recompile?
I have recently compiled linux kernel 3.2. But at time of compiling in make menuconfig, I had disabled sound support.
Now, I want to enable it without recompile it. I don't want to use stock kernel ...
1
vote
3answers
303 views
Why does Linux on sparc64 architecture use 32-bit pointers in user-space and 64-bit pointers in kernel-space?
What are the advantages of deviating from the norm; that is 64-bit pointers in both user and kernel space for a 64-bit architecture?
Reference: http://lwn.net/images/pdf/LDD3/ch11.pdf (Page 2)
2
votes
0answers
363 views
Qemu doesn't boot kernel after “Uncompressing Linux… done, booting the kernel. ”
I've compiled qemu for s5pc110 (it's from http://gitorious.org/samsung-linux-platform/qemu, somebody had added support for s5pc110), version 0.12. But when I load the kernel:
qemu-system-arm -M ...
10
votes
3answers
7k views
How to reload udev rules without reboot?
How should one reload udev rules, so that newly created one can function?
I'm running Arch Linux, and I don't have a udevstart command here.
Also checked /etc/rc.d, no udev service there.
13
votes
3answers
850 views
Why don't you need to update drivers? (Or do you?)
In my life I've not once updated drivers on any of my Linux systems, though they have all been desktops. A friend was asking me why one does not need to update Linux drivers and I found myself unable ...
0
votes
0answers
284 views
Troubleshooting Bug: Soft Lockup
We're having some trouble here with "soft lockup"s in our /var/log/syslog. The system seems to freeze for 10-70 seconds, then comes back. This is affecting web serving and other key processes. It ...
0
votes
0answers
30 views
What happens after an USB disk is connected to a Linux system? [duplicate]
Possible Duplicate:
What happens when a USB drive is plugged in?
What happens after an USB disk is connected to a Linux system? Does the system probe devices, load driver modules, or what? ...
5
votes
1answer
336 views
Needs help on setting up kernel keyboard mapping
I already got the keycode from kernel, but acpi_listen won't recognize it in Arch Linux:
# /usr/lib/udev/keymap -i /dev/input/by-path/platform-thinkpad_acpi-event
Press ESC to finish, or Control-C if ...
1
vote
2answers
91 views
2
votes
1answer
968 views
No vmlinuz and initrd after building the kernel?
After configuring and building the kernel using make, why don't I have vmlinuz-<version>-default.img and initrd-<version>.img, but only got a huge vmlinux binary (~150MB)?
2
votes
1answer
166 views
Which edac module should I enable here?
I got a Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz CPU here , not sure which module should be enabled for EDAC:
Chipset: Inter Coporation 6 Series/C2000 , driver in use: i801_smbus
3
votes
2answers
586 views
How do I build the iptables kernel module for a loaded kernel?
I've built a kernel with loadable module support for various reasons, one of them the possibility to compile modules and load them without rebooting. This is supposed to be useful when I need a module ...
0
votes
1answer
433 views
Can the Linux kernel be compiled on Mac OS X 10.6.8?
I have a Macbook Pro and I want to build the Linux Kernel. Can I build 3.3.6 on my Mac? How?
3
votes
1answer
299 views
Do I have to list modules in both `/etc/mkinitcpio.conf` and `/etc/rc.conf`?
I've added few modules into mkinitcpio.conf.
Are they automatically loaded at kernel boot or with udev if I don't specify them in modules list in rc.conf?
5
votes
2answers
821 views
VirtualBox guest: 16 CPUs detected but only 1 online
I am running VirtualBox (using the Qiime image http://qiime.org/install/virtual_box.html)
The physical hardware is a 32 core machine. The virtual machine in VirtualBox has been given 16 cores.
When ...
3
votes
1answer
71 views
What does CONFIG_IA32_AOUT do actually?
I'm running a 64bit kernel, already have CONFIG_IA32_EMULATION set, so do I still need CONFIG_IA32_AOUT enabled?
From the help in menuconfig, I don't quite get it.
12
votes
3answers
3k views
How can I reserve a block of memory from the Linux kernel?
I have a device that needs a block of memory that is reserved solely for it, without the OS intervening. Is there any way to tell BIOS or the OS that a block of memory is reserved, and it must not ...
22
votes
1answer
1k views
High CPU usage with CFS?
I asked a previous question to try and isolate the source of an increase in CPU usage when moving an application from RHEL 5 to RHEL 6. The analysis that I did for that seems to indicate that it is ...
