The kernel of operating systems popularly known as Linux, or sometimes GNU/Linux.

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.config not getting updated after modification to tegra3_android_defconfig

.config not getting updated after modification to tegra3_android_defconfig After adding a module(MODULE_XX_CONFIG=y) inside tegra3_android_defconfig, I did "make tegra3_android_defconfig" though the ...
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32 views

Using two memory controllers with SPARSE_MEM on AT91SAM9G45

There are lot posts on this problem in google, but I have tried all the solutions but they are not working for me, so I'm posting here… I am working with AT91BootStarp 3.5.9 with linux kernel 3.6.9. ...
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2answers
250 views

What files does the Linux kernel access?

/init during early userspace, /sbin/init, and /sbin/request-key are three files that the Linux kernel accesses (and they are all executables). Are there any other files, possibly non-executable ones, ...
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6answers
11k views

Why is the Linux kernel 15+ million lines of code? [closed]

What are the contents of this monolithic code base? I understand processor architecture support, security, and virtualization, but I can't imagine that being more than 600,000 lines or so. What are ...
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33 views

Replacement for cap-bound

We have an old Linux from scratch kernel used in one of our systems, that uses the old cap-bound mechanism (modifying /proc/sys/kernel/cap-bound) to restrict the capabilities of the system. This was ...
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111 views

Wifi driver on Kernel 4.x

I've upgrade my kernel from 3.19 to 4.1.5 but the Wifi driver don't work. Does anyone know how I can make it work? I've tried a few methods but it doesn't work. First method I've tried was to try ...
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3answers
131 views

How can I verify `nice` is working?

Looking at different jobs running on a system with shared resources, it seems the nice values are being ignored. Many jobs with nice set at 19 are running at 100% cpu load while other many other jobs ...
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1answer
827 views

CPU warning - abrt-watch-log

I am running a Red Hat Enterprise Linux Server release 7.1 (Maipo) on Intel(R) Xeon(R) CPU X5690 @ 3.47GHz I keep getting this error in abrt-watch-log. root 888 1 0 Aug03 ? ...
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36 views

Print kernel memory layout

Userland memory layout can be inspected by looking into /proc/self/maps. I am wondering if there is a similar facility allowing to inspect runtime kernel memory layout?
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19 views

Do less severe log level INCLUDE more severe log levels?

Will loglevel=7 include the logs, for example, that would be produced by loglevel=0? http://www.makelinux.net/ldd3/chp-4-sect-2
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30 views

Unattended build of linux kernel

Goal: I am trying to automate the 4.0.4 kernel build to provision it to multiple machines. Since AUFS no longer ships in "extras" package, I am compiling it as well, and then adding via make ...
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76 views

Where do these boot log entries come from and who creates them?

I'm wondering what kind of code writes these first two lines into /var/log/syslog while booting my machine: Aug 4 10:13:48 HOSTNAME kernel: imklog 5.8.11, log source = /proc/kmsg started. Aug 4 ...
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298 views

Process which locks up, ignores SIGKILL, is runnable (not a zombie or in uninterruptable sleep). What state is it in?

I have a process which several times now has stopped responding and appears to be completely locking up. It doesn't respond to any attempt at strace or peeking with gdb (gdb just hangs on a wait4() ...
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1answer
51 views

Increasing Kernel Mode Setting (KMS) scrollback buffer size

I'm using Kernel Mode Setting to set my server's tty resolution. I added GRUB_GFXMODE=1280x1024x24,auto to /etc/default/grub, and GRUB_GFXPAYLOAD_LINUX=keep was already there. There's no vga= or ...
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1answer
267 views

Unable to install new kernel in ubuntu server. “gzip: stdout: No space left on device” error even though abundant disk space

I am trying to install a new kernel on Ubuntu Server and I am unable to complete it due to a "gzip: stdout: no space left on device" error. The full error was produced after running sudo make ...
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1answer
44 views

Is it possible to delay booting the system after the user has pressed the power button? [closed]

I want to delay the time to load the kernel after the user has pressed the power button by 10 seconds. Reasons for this is a machine we have built which requires other components to start sending data ...
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2answers
610 views

Uboot passes arguments to kernel!

How can uboot pass command line argument to kernel? I did some googling and got to know that it uses the bootargs environment variable. There it was mentioned that setenv bootargs key=value. Since I ...
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1answer
36 views

Recompile kernel without modules that are not currently in use

Is there a neat way of stripping the Linux kernel to only support the devices that are currently in use. After NVIDIA complaining about GCC version mismatch, I decided to recompile the kernel with the ...
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32 views

What is the Linux scsi mid-layer

In the Linux storage stack there are 3 levels: upper, mid and lower. Therefore, I know what it is in that sense. What I'm hoping someone will know is, what files in the Linux source tree actually ...
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1answer
222 views

Kernel address space layout

Userland address space is well documented, which includes segments like heap, stack, .text, .bss, etc. But there is not enough documentation on kernel address space. Since certain virtual address is ...
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31 views

Kernel config diffs - better way to maintain

I maintain one Linux distro (LEAF) with multiple kernel targets, so it needs to have multiple kernel configs (one reference config + usual patch files for other targets). But this adds headache on ...
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1answer
126 views

what's difference between src version 3.* and 3.*-generic

In my local Linux/Ubuntu, I have two directories for Linux src /usr/src/linux-3.16.0 /usr/src/linux-3.16.0-generic I found the code in 3.16.0 is much more than that in 3.16.0-generic. I am ...
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2answers
96 views

Wrong eUID in `/proc/PID/status` when SETUID is used

While doing a wargame challenge, I ran into an issue with permissions. The info given by /proc/PID/status is not in adequation with the permissions that should be given to the processus. I am user ...
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71 views

Debian instance has two Kernels after installing Intel PCIe SSD drivers - one with Black screen

I am using Debian 8 and after installing Intel PCIe ssd drivers I noticed that the are two kernels. The kernel which has the Intel drivers installed does not display the desktop, only a black screen. ...
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108 views

RAM Disk related questions [duplicate]

there is a developed kernel subsystem that needs a chunk of memory allocated to itself that only it could manipulate this chunk. this memory should be physically contiguous and also it need the access ...
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832 views

/dev/mmcblk0 partitions limit

I've just mounted a microSD card which has 17 partitions in my laptop and I'm getting the following error in the YaST partitioner: Your disk /dev/mmcblk0 contains 17 partitions. The maximum number of ...
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1answer
52 views

Linux kernel build : shouldn't make <manufacturername>defconfig yield the same .config file?

I'm building a cross compiled 3.2.15 kernel for a Marvell Armada 370 system. The vendor's default config file for this is armada_370_v7up_defconfig. So when I perform a make ...
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3answers
85 views

How Linux kernel gets built [closed]

I am new to Linux and I would like to know how the Linux kernel gets built. Who builds this? I have heard that Linux gets built by programmers sitting all over the world. But it gets only released by ...
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1answer
379 views

NMI received for unknown reason 20 — Do you have a strange power saving mode enabled?

I am using Debian GNU/Linux 7.8 (wheezy). While running my MATLAB program today, I got this message in terminal. Message from syslogd@sas21 at Jul 18 16:40:49 ... kernel:[1747708.091929] Uhhuh. NMI ...
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1answer
36 views

Is a disabled kernel option equivalent to not loading the corresponding module?

Suppose I set a tristate kernel configuration option to be built as a module, but I don't load the corresponding kernel module at runtime (and it doesn't get loaded automatically). Is the ...
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27 views

How to troubleshoot Fedora kernel bug

Bug 1236215, reported to the Redhat bugtracker has not gotten any attention in over 3 weeks. I'm trying to track down the cause myself, but I'm not sure how to proceed. The problem was introduced in ...
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41 views

Why does Linux scheduler have locks for run queues?

Why does Linux Kernel Scheduler code have locks for run queues? Does the scheduler spawn kernel threads, and locks are to prevent two of such threads to avoid modifying run queues at the same time?
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40 views

edit module requirements when compiling kernel

I would like to compile the realtime kernel for raspberry pi (https://github.com/emlid/linux-rt-rpi) and want to use the pi with a soundcard - the tascam us122l. The problem that I have is the ...
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36 views

Why am I able to compile kernel modules without “#include”ing the relevant header files?

Based on the common practices shouldn't I have to include <linux/stat.h> and <linux/module_param.h> in the following program? #include<linux/module.h> char str[7] = "hello"; int ...
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1answer
56 views

Difference between Current and RC Kernels?

What's the difference between wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-rc1-unstable/linux-headers-4.2.0-040200rc1_4.2.0-040200rc1.201507051635_all.deb and wget ...
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1answer
65 views

Modify the graphical parts of the Android OS [closed]

I’m going through the Android kernel and Google Glass kernel, and I’m trying to find the graphical parts of the operating system. I want to modify things like the splash screen displayed while the OS ...
3
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1answer
168 views

Why can the waitpid system call only be used with child processes?

The man page wait(2) states that the waitpid system call returns the ECHILD error if the specified process is not a child of the calling process. Why is this? Would waiting on a non-child process ...
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73 views

How to confirm CONFIG setting made with make menuconfig?

I poke around make menuconfig select this, deselect that. Rebuild a linux kernel and boot up with it. How can I confirm the selection(s) I made via menuconfig exist after booting? lsmod?
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Where is the RHEL7 kernel source code installed?

I install the Linux kernel source code RPM: [root@localhost ~]# rpm -ivh kernel-3.10.0-229.el7.src.rpm warning: kernel-3.10.0-229.el7.src.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY ...
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1answer
134 views

What is difference between different cpu.cfs_period_us values?

I'm reading kernel[1] docs and confused about the cpu.cfs_period_us in this part: 3. Limit a group to 20% of 1 CPU. With 50ms period, 10ms quota will be equivalent to 20% of 1 CPU. # echo ...
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1answer
256 views

Where in the kernel /dev/kmsg gets initialized?

I'm trying to figure out at which point in the boot up process /dev/kmsg gets initialized and can thus be written. On my system the first line that occurs in dmesg is printk(KERN_INFO "Initializing ...
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1answer
152 views

ACPI – how to select correct LED and LCD module

I'm facing a strange issue. I have ASUS x551ma notebook; As I can get it, after a while (20-30 min) watching LCD, I suffer eye strain. The graphics (video card) seems fine but the LED is micro-shaking ...
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34 views

How to add version number to custom kernel and rootfs?

I have a small embedded project where I had to make some minor tweaks to a linux kernel to support different hardware and minor tweaks to a debian-based operating system (my rootfs). uname -a no ...
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155 views

Custom driver for keyboard GNU/Linux 4.1.0-rc8 (Fedora)

I am writing a driver for a Logitech G110 USB keyboard for Kernel 4.1.0-rc8. My driver is perfectly loadable with insmod (Debugging message prints to dmesg that it get's initialized through ...
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1answer
101 views

Kernel panic? After ram increase

We asked our server provider to increase ram (from 4gb to 6gb) on our server. After they increased and restarted server, it started giving these messages: Message from syslogd@www at Jul 1 14:39:04 ...
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104 views

Why does my process take too long to die?

Basically I'm using Linux 2.6.34 on PowerPC (Freescale e500mc). I have a process (a kind of Virtual Machine that was developed in-house) that uses about 2.25 G of mlocked VM. When I kill it, I notice ...
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103 views

How does rootfs.ext3 image file work?

I have a FriendlyARM mini6410 device and I have just hardly make it boot from sdcard. Now my sdcard uses "u-boot for mini" (u-boot.bin), "linux2.6.38 kernel" (zImage) and "rootfs qtopia fs" ...
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29 views

How to catch my bluetooth service events

I have usb bluetooth device which is using btusb 0.6 module (driver). The thing is I am interested to know is: how is the systemctl start bluetooth.service event invoked? I was looking info about ...
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1answer
46 views

How to determine if the kernel sources are installed?

I just bought a USB 3.0 Gigabit ethernet adapter. It uses an ASIX ax88179_178a driver. I need to build the driver and the readme says: ...you need the Linux kernel sources installed on the build ...
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245 views

Can a kernel preemption happen in the process context with `TASK_INTERRUPTIBLE` state?

If a process sets itself to the sate of TASK_INTERRUPTIBLE, can it be preempted by other kernel components? If it does, I think this process maybe lost wake-up chance due to failed to check the ...