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

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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 ...
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25 views

Kernel bisect: when a patch is failing for a reason other than original bisect purpose, what do you do?

Let's say you're trying to find the cause of a bug between 3.11.0 and 3.12.0. The bug is really difficult to catch, because it may or may not manifest itself over several days of regular workload ...
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31 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 ...
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429 views

After installing a new Kernel in Ubuntu 14.04, rebooting takes me to busybox initramfs. How do I mount a filesystem after that?

I have a virtual machine with Ubuntu 14.04 in it. I recently built and installed linux-3.14.5 kernel on it, and tried to boot into it, but it drops me to BusyBox v1.21.1 built-in shell. Here's what I ...
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349 views

Debian driver needed for Intel ICH7M SouthBridge I/O controller

I am using a motherboard based on this architecture. http://www.intel.com/content/www/us/en/intelligent-systems/navy-pier/embedded-intel-atom-n270-with-mobile-intel-945gse-express-chipset.html I ...
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200 views

Enabling GPIO in kernel not working

I have tried to enable the GPIO pins for my system through the Kernel but I am not able to get them to work. When I try this: echo 1 > /sys/class/gpio/export The terminal window just closes. ...
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179 views

How to enable VESA framebuffer as default in NetBSD 6.1

When booting NetBSD, the old Tecra 720CDT that I have, works quite nicely in 1024x768x15 mode with vesa fb. I always have to activate VESA when booting the system: > vesa on > vesa 0x116 > ...
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141 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 ...
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52 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 ...
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Kernel crash on Fedora distribution but no sign of kernel panic

I am running kernel 3.14.4 on Fedora 18. I am experimenting with a kernel module I am making. The module has a bug (at least one) and crashes the kernel. Sometimes I see a stack trace on my frozen ...
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182 views

Wireless constantly reconnecting on Ideapad running Arch

I just bought a new laptop, a Lenovo IdeaPad U330 touch, and after some struggle (with the Secure Boot stupidity) I have managed to install Arch Linux. I have configured my system, installed all the ...
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199 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 ...
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89 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 ...
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581 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 ...
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223 views

TUN/TAP Will not load

I have an OpenVZ server but can't seem to get the tun/tap module to load. I ran modprode tun on the hostnode but when I go under the VM I get: Tue Sep 24 03:08:36 2013 Note: Cannot open TUN/TAP dev ...
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584 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 ...
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113 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 ...
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52 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 ...
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257 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", ...
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487 views

Kernel does not detect Hardware / Software or Hardware fault

I've got more of a basic question for you: My linux kernel (I tried several here from stock 2.6, 3.2 and 3.5 as well as a custom 3.7.3 one) does not detect my synaptics touchpad - or I'am too dumb ...
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290 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 ...
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328 views

Delayed write scenario

I was reading the design of unix OS 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 from the free list. ...
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86 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 ...
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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 ...
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101 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 ...
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394 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 ...
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610 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 ...
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215 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 ?
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410 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 ...
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169 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 ...
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218 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. ...
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593 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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22 views

CPUFreq Kernel module

I would like to try the CPUFreq module on my board (Marvell Soc based on ARMv7 running a v3.15 linux kernel). My architecture is obviously not supported by the default source code (located in the ...
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cross compile embedded arm

I have the android 4.2.2 code in directory /home/sghPhone2 which compiles normal with make menuconfig but I need to compile a 4.4 kernel and possibly patch it but when I download the source from ...
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43 views

What does this “general protection fault” in my console mean, and how do I interpret it?

I had a couple of consoles open for other work and when I came back to them they both contained the following: Message from syslogd@Stacey-Windows at Jun 19 09:43:28 ... kernel:[ 4375.127165] ...
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29 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 ...
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24 views

Adding IPVS to the kernel

I am trying to setup keepalived on a pair of VPS load balancer servers. I have hit the road block of IPVS not being included with the kernal. IPVS: Can't initialize ipvs: Protocol not available I ...
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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 ...
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44 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 ...
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73 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 ...
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64 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 ...
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23 views

How to correctly set kernel command parameter for sdboot

Thease are the kernel command line parameter Kernel command line (user set) root=/dev/mmcblk0p2 rw rootwait console=ttyPS0,115200 I am trying to run linux from sd card, and the file ...
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103 views

Looking for a list of modules that are used during boot sequence

I'd like to use deferred init calls. This function allows to load modules in userland, that should actually be loaded during the boot sequence. Just for testing I'd like to modularize as many entries ...
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1k views

How to get back from “testing” to “stable” - Kernel downgrade

currently I am having lot's of fun with apt-get - and the bad thing is, it was my own fault. I had enabled the testing packages in /etc/apt/sources.list to install a certain package. And I told my ...
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124 views

D-Link usb dongle detection problem [ Debian Wheezy ]

according to this topic,I was upgrade kernel from 3.2 to 3.12 (using .deb backport),But at installation process I get some error message like this : # dpkg -Ri kernel3.12 Selecting previously ...
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57 views

How to disable PAE feature of kernel, after installation?

I am using RHEL 5.3(x86) as a base platform for my development purpose.My machine's spec is as follows: Intel, Core-i3 Processor @ 2.5GHz 4GB RAM Problem is whenever I am attempting to install the ...
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31 views

Patching the kernel source through git

I'm trying to understand how the patching of the kernel source works. I found the patch that I would like to try an apply on the following page. I found no .patch files that I can use to apply the ...
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55 views

kernel 3.1x and optimus support

I have encountered a negative observation regarding bumblebee. Namely, using optirun the performance of the GPU seems to be an order of magnitude lower than it should be. To be more specific: I have ...
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1k views

kernel: “echo 0 > /proc/sys/kernel/hung_task_timeout_secs”

I got this errors in syslog. Any idea what does it mean? The system is running on Ubuntu 12.04, kernel: 3.8.0-35-generic #52~precise1 It looks to me like failure when trying to write to disk... ...
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sysrq-trigger doesn't accept parameter 'g'

I'm trying to debug the kernel. But I couldn't trigger kgdb with echo g > /proc/sysrq-trigger, it just prints help message. I have enabled kernel debugging, kgdb over serial, frame pointer etc. ...