Everything about UNIX kernels: development, configuration, compilation, design, etc.

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11
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314 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 ...
4
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257 views

Centos 7 boot up with custom kernel problem

I have installed centos 7 on virtualbox machine which has kernel-3.10.0-123.20.1.el7.x86_64. I am trying to build Linux kernel from kernel sources. I downloaded the kernel source files from: ...
4
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614 views

dmesg: pci BAR 7: can't assign io

I have VMware virtual machine running Debian Wheezy. I have compiled my own kernel 3.14. I have noticed dmesg is flooded with messages pci BAR 7: can't assign io (size 0x1000). I have no idea what ...
3
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38 views

ABRT report says “irq 19: nobody cared”, but why?

Every couple weeks, I need to reboot my system. When I do, and enter as root in the terminal, the following message (in some variation) appears: ABRT has detected 3 problem(s). For more info run: ...
3
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25 views

What could cause dropping cache to be extremely slow on a large cluster?

I'm attempting to time file I/O on my disks. In order to make sure all the I/O is happening off the hard drives and not from ram, before I time any read, I run a drop cache command. Specifically, I ...
3
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590 views

update kernel without restart

Recently Linux got a new feature called Live Kernel Patching, which you means you dont have to restart your system to update kernel. Is there any other kernel which has this feature already or Linux ...
3
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226 views

How to prevent kernel or any broadcast messages from flooding the TTYs?

Because of some hot-plugging issue, similar to what talked of here, the TTY displays show a continuous stream of messages (which are also logged in the /var/log directory). Every text I key in flows ...
3
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52 views

Why does each process folder under /proc contain the same information?

Under /proc/<PID>/net pseudo-file system each process seems to have files with the same content. For example I use cat /proc/<PID>/net/ip_tables_names to list iptables tables under the ...
3
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330 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 ...
3
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471 views

graph TCP connection performance based on `ss -i`

A nearby question has brought to my attention the ss utility on Linux, another utility to investigate sockets. It would appear that it may be a great tool to monitor the performance of, say, an ssh ...
3
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183 views

Can I get WCHAN from ps on Mac OS X 10.7.4?

From the manual it seems that ps -AO wchan should tell me what everything is sleeping on, but everything comes up as -. (And nwchan as 0). Did they do away with the old sleep()/tsleep() interface in ...
3
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2k 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 ...
2
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7 views

What is “state-object” in cgroups

I am gathering some idea about lxc, kernel name spaces and cgroups. While reading man lxc-cgroup, i find : lxc-cgroup gets or sets the value of a state-object (e.g., 'cpuset.cpus') in the ...
2
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30 views

File permissions for kernel have changed in OSX Yosmite, why?

I am working my way through the book Learning Unix for OSX Mountain Lion (I don't have access to the updated version for OSX), in which it demonstrates that using $ ls -l /mach_kernel should ...
2
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23 views

Significance of Linux kernel's default_console_loglevel

What is the significance of default_console_loglevel in Linux? Commonly I see it described as the default value of console_loglevel. However, what that means I haven't seen explained anywhere. ...
2
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80 views

How to explain strange kernel messages?

I have a server running on Debian Wheezy 3.2.68-1+deb7u1 x86_64. Lately strange records in /var/log/messages appeared. First messages of this log starts just after server reboot. 6.222.18 LEN=44 ...
2
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22 views

Using dkms to patch kernel

I need to apply a kernel patch(https://lkml.org/lkml/2015/3/31/929) to get my touch-pad working properly. I am thinking that I should be using dkms, to do this. Most of the stuff I am reading is about ...
2
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82 views

is THP good or bad for MySQL Server?

Linux kernel new feature called Transparent Huge Pages (THP) which is by default enabled on CentOS 6.x and above OS. Is THP good for MySQL DB machine? I am trying following to disabled THP but seems ...
2
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77 views

USB keyboard is disconecting automatically (without being unplugged)

In my log, I see following message: kernel: usb 1-1.6: USB disconnect, device number 5 acpid: input device has been disconnected, fd 7 acpid: input device has been disconnected, fd 8 I have not ...
2
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40 views

Improve kernel boot time

I am using OMAPL138 and kernel version 2.6.37 and I would like to improve the boot time. By analyzing the kernel boot process I think it is taking a long time at MII PHY CONFIGURATION. The printscreen ...
2
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45 views

Debugging info in linux kernel - how does it work?

I have found that I can compile linux kernel with some flags adding debugging support like CONFIG_DEBUG_INFO. These options while useful in debugging are also required by some utilities like ...
2
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1k views

Install rtl8188etv/rtl8188eu driver on Orange-Pi

I'm trying to install the wifi driver on Orange-Pi board. The real chip is rtl8188etv but the driver is the same. I have compiled 3.4.105+ Kernel to have the headers: mkdir ...
2
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72 views

View syscalls/kernel activity for I/O from a running process

I'd like to be able to view syscalls or kernel activity for a process...I'm not actually sure of the terminology I need here! Specifically I'm looking for the difference between I/O going to local ...
2
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321 views

How to suppress input overrun messages

I have a Raspberry Pi running Raspbian (a Debian flavor: Linux version 3.12-1-rpi (debian-kernel@lists.debian.org) (gcc version 4.7.2 (Debian 4.7.2-5+rpi1) ) #1 Debian 3.12.9-1+rpi1 (2014-05-19) ). ...
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263 views

Explanation of the building process of the kernel on Ubuntu/Debian systems

I'm getting into Linux kernel programming and I have successfully built my own kernel several times now. However, I have done it using step by step guides found from the internet and I don't really ...
2
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170 views

Why will plymouth not update?

I admit I don't update my kernel very often. I used to everytime a stable release of sys-kernel/gentoo-sources came out so I'm very adept at doing it. This last weekend I attempted to update from ...
2
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46 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 ...
2
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138 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
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169 views

Debugging a “brutal” system hang (no longer responds to Alt+SysRq+B)

I've had a series of system hangs where I hoped to get a crash dump to at least get some clues but the normal "magic sysrq" functionality is broken too; not even the immediate reboot key works. The ...
2
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262 views

How can I compile minix when I make changes in libraries

I am looking for a way to compile minix. The make hdboot command seems to do nothing with the directories under /usr/src/lib. I changed only one .c file in syslib. Do I have to do make world for this ...
2
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1k views

“Kernel panic - not syncing” after building Centos-6/elrepo 3.10.19 kernel from source

I need to rebuild the Centos-6 / elrepo 3.10.19 kernel from source. Background: the GVision touch screen drivers are incompatible with kernels > 3.8 and require source code patches to add code to ...
2
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853 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 ...
2
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1k views

Unable to install the selected kernel

I have problem with my DVD drive. It's corrupted and when I'm trying to install Ubuntu it stucks (even with the miniISO) I was able to successfully start the OS from system rescue CD. I'd like to ...
2
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0answers
146 views

Is there a way to undo VGA adapter modesetting in Linux

I'm looking for a way to reset the graphics adapter to textmode after it has been set to some sort of graphical mode by the kernel on bootup, and possibly used by an X server. Is there any code to do ...
2
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0answers
61 views

kgdb not returning control to gdb

I've compiled a kernel with kgdb support and I'm trying to debug it. I have two machines running, a debug machine (running the kgdb kernel) and the machine I'm using to debug it. They are connected ...
2
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406 views

Failed to execute shell script from “network” udev rule to change the MAC-address

I am trying to execute a shell script from udev rule, when a network interface is added, as follows: SUBSYSTEM=="net", ACTION=="add", KERNEL=="eth*", PROGRAM="/usr/local/bin/changemac.sh", ...
2
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495 views

Booting over the LAN using uboot

I am trying to boot my beaglebone over the LAN. I am able to download the Kernel uImage from the TFTP server. Here is what I did - U-Boot SPL 2011.09-00053-gb423c52 (Aug 10 2012 - 11:26:55) Texas ...
2
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514 views

Delayed write scenario

I was reading "The Design of the UNIX Operating System" by Maurice J. Bach and had a confusion. Suppose a process requests for a buffer for disk block number 18. The kernel searches for a free buffer ...
2
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105 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 ...
2
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0answers
82 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
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0answers
162 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 ...
2
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0answers
554 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 ...
2
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0answers
805 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 ...
2
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0answers
281 views

Perform test of aes-ni and aes module in linux kernel

Since both aes-ni and aes module are available in linux kernel , how can I give it a performance test , to decide which one's faster ?
2
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646 views

To what does the byte sequence in this kerneloops (syslogd@hostname) message refer?

Message from syslogd@ROOROO at Mar 22 19:36:12 ... kernel:[13988.165672] Oops: 0000 [#1] SMP Message from syslogd@ROOROO at Mar 22 19:36:12 ... kernel:[13988.169607] Stack: Message from ...
2
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0answers
185 views

What are the current differences between tuxonice and µswsusp?

I tried to find out what is the current comparation between TOI and µswsusp. Unfortunately I could not find any recent information about the state of hibernation in Linux and how TOI compares to ...
2
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0answers
257 views

Uname gives unfamiliar timestamp for kernel

I'm recompiling a new kernel (adding some debugging info) on Ubuntu by doing the following: make vmlinux; make install; after this I do a reboot and select my new custom kernel from the list. ...
2
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0answers
872 views

Linux kernel slab usage growing on embedded system

I'm in the process of QA/debugging a project on a custom embedded linux system. The problem we're VERY tight on memory, and even a couple megs can cause issues with our software. What I'm seeing ...
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9 views

Is there something like “make localmodconfig” that detects *all* your hardware?

I understand that Linux's "localmodconfig" target looks through all your loaded kernel modules and produces a .config file that enables those modules. This is nice, but what about hardware whose ...
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11 views

Best way to approach HID_MAX_USAGES kernel errors?

This is an issue I have for the second time now: basically, an USB based device reports some wrong numbers for "HID_MAX_USAGES", resulting in the kernel giving an error message and the device not ...