Everything about UNIX kernels: development, configuration, compilation, design, etc.
0
votes
2answers
19 views
Updating kernel but not packages
I need to update the kernel from version 2.6.30 to 2.6.37. I'm going to just compile the kernel and kernel modules for this architecture and boot it. But also there are a lot of packages installed, ...
0
votes
1answer
15 views
What part of TTY subsystem control the active /dev/ttyN (TTY device driver N)? [on hold]
TTY subsystem contains TTY driver, line discipline and hardware drivers (keyboard driver, display driver). Let's say I use a terminal emulator. So, my current session uses /dev/tty1 (TTY driver 1). ...
0
votes
0answers
24 views
bash's pseudo terminal master [duplicate]
I learn when we use pts, there is master of pts.
Then, when we type the characters on the pts(which is the terminal of bash), not only the output of bash goes to pts but also its master?
I confirm ...
1
vote
1answer
31 views
Cannot compile a linux kernel for an ARM board [on hold]
I am trying to compile a linux kernel (2.6.32.70) for an ARM board (versatilepb), it is my first steps in embedded linux.
At the end of the compilation, two compressed kernel images are generated ...
18
votes
4answers
890 views
What exactly happens when I execute a file in my shell?
So, I thought I had a good understanding of this, but just ran a test (in response to a conversation where I disagreed with someone) and found that my understanding is flawed...
In as much detail as ...
0
votes
0answers
15 views
Help debugging a kernel oops
My system has been freezing up for a while, and I keep seeing this particular kernel oops: syslog. Xorg.log
Here's another similar crash from a few months ago. syslog
Can you help me debug this? How ...
0
votes
1answer
29 views
Not able to cross-compile 8192cu kernel module for ARM [on hold]
I'm trying to compile a module out of tree.
make -C <path to src> M=$Pwd modules ARCH=arm CROSS...=arm-linux...
The compilation works fine and I don't get any errors but the final result is ...
0
votes
0answers
16 views
Loop device support on self compiled kernel doesn't work
I compiled 3.10 kernel, I checked that these configuration lines are not commented
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_LOOP_MIN_COUNT=8
When i'm trying to mount loop device I get this error
# ...
0
votes
0answers
9 views
Kconfig (bool/def_bool/tristate)
In a Kconfig file, what are the differences between :
bool
def_bool
tristate
Thank you.
0
votes
0answers
21 views
perl script stall nanosleep() call in strace output
I have perl base SIP client which calling for SIP REGISTRATION process but i am seeing it stall for 10 second at nanosleep() call
send(4, "REGISTER sip:sip.example.com S"..., 513, 0) = 513
select(8, ...
0
votes
1answer
12 views
CPU: 13 PID: 15452 Comm: ssd_blk/0 Tainted: G B I E 3.19.0+ #1
I developed a module which works as an emulator for a block device. When I write into the block device, I get this in dmesg and the module crashes. I cannot get any hint about what is going on?
...
0
votes
1answer
26 views
How do I know which File Systems my linux supports? [duplicate]
I am working with linux 3.19.0+ and I want to know if my linux kernel supports f2fs (Flash-Friendly File System). How do I know that?
3
votes
0answers
20 views
How to switch static drivers like switching kernel module drivers?
I have a linux embedded device that I need to switch between USB file storage gadget driver and USB Ethernet gadget driver at runtime.
The approach I use now is to build both drivers into kernel ...
1
vote
1answer
24 views
How can strace monitor itself?
I have a Hypothetical Situation.
(1) Let us say we have two strace Processes S1 & S2, which are simply monitoring each other.
How can this be possible ?
Well, in the command-line options for ...
0
votes
0answers
12 views
What is the role of these RPM packages（ kernel-debuginfo and kernel-debuginfo-common RPMs, and the kernel-devel RPM）?
I want to know what the role of these RPM packages( kernel-debuginfo and kernel-debuginfo-common RPMs, and the kernel-devel RPM)?
0
votes
1answer
20 views
Unable to boot a kvm guest via qemu/kvm-tools
I am using ARM Foundation Model to emulate a arm-v8 environment(I need both TrustZone and KVM), and I run a kvm-enabled linux on it as the Host OS, the kernel version is 3.14.0(I clone it following ...
1
vote
1answer
41 views
Desktop completely freezing on I/O operations
In my old system, I was already having desktop freezes on some heavy I/O operations like apt-get dist-upgrade and copying 4 GB video files. But now, it has become a lot worse: any apt-get install is ...
0
votes
0answers
13 views
Why do the clone_flags of do_fork() have different naming conventions? [migrated]
Recently I am studying Linux Kernel Programming and I found some weird things. The clone_flags of do_fork() are listed in <uapi/linux/sched.h>, but I found they have different naming conventions ...
0
votes
1answer
59 views
Linux + how to know why Linux machine is hung from the messages on the console
As the picture below , my VM Linux machine was hung and I cant login
how to identify the reason for the "hung" according to the messages on the console?
I also searched more info from the ...
-1
votes
0answers
16 views
How to disable ehci_hcd driver during booting
i am using rhel 5.3 Linux , i m getting error- 71 if USB hub connected.. i want to disable USB ehci_hcd driver in kernel level. i tried blacklist and added script( echo-n"0000:00:1a.7" > ...
1
vote
2answers
21 views
Efficient way to deploy a custom kernel onto multiple hosts
I recently had to do a custom build of the Linux kernel from its source.
That custom kernel is now installed on the machine I used to build it and works fine.
Now there are other similar systems ...
0
votes
0answers
20 views
How to interpret some kernel OOPS output?
I'm trying to analyze some kernel OOPS message. I'm able to understand most of the output, but there's still some lines that I have no idea how the should be interpreted.
The first thing is PGD which ...
1
vote
0answers
36 views
CentOS 7 unable to cleanly umount a bind mount using rbind and rslave
The following sequence of commands will fail on CentOS 7 (kernel version: 3.10.0-327.10.1.el7.x86_64):
[hidden]$ mkdir -p A B/a C/b
[hidden]$ sudo mount --bind A B/a
[hidden]$ sudo mount --rbind B ...
-3
votes
1answer
82 views
Find Linux kernel build date/time?
In a Linux distro, let's say Ubuntu 14.04, how can one find the time and date when this particular Linux Kernel was compiled/built?
0
votes
1answer
24 views
module not loaded at boot
I'm on an archlinux 4.4.1-2 and I'm trying to set up a netctl service.
Problem is that for netctl to work I need to have bcma and b43 loaded.
Since these two are not out-of-tree modules I thought I ...
0
votes
1answer
34 views
why process running in kernel mode cannot be preempted [duplicate]
I read that user mode process are preemptive but why not kernel mode process?
1
vote
2answers
55 views
Differences between system processes, and user processes, kernel control paths and kernel thread
My understanding is that
a process always runs in user mode and uses user space only, and
a kernel always runs in kernel mode and uses kernel space only.
But I feel that I might not be correct, ...
0
votes
0answers
10 views
How does vfs_write decide to aio_write of which file system?
We know that sys_write call vfs_write that ultimately call fs->f_ops->aio_write.But how does kernel know which filesystem's aio_write call back function to call??
Moreover I have noticed that ...
0
votes
1answer
66 views
Why are Linux versions so confusing?
I was browsing through kernel.org pages and reading changelogs from several different Linux kernel versions. I noticed the version number pattern is extremely awkward:
From Linux 2.6.x came Linux ...
2
votes
2answers
43 views
How to find out the reason why ssh processes are hanging?
When I run command like iostat -dkx 2 2 via ssh, I get the expected result, but the processes on the local computer are saying alive in status "interruptible sleep". Why is this happening? Is there a ...
1
vote
0answers
21 views
How to Modify Android Boot Sequence in Order to Boot From an SD Card
I've been looking into how to boot Android form an SD card, and I came across this thread on XDA, but I am too much of a noob to understand it, and user has stated that she doesn't have the time to ...
2
votes
0answers
27 views
Mysterious 8 second delay in boot after grub
I have installed Fedora 23 (KDE spin) on an HP Prodesk mini 600 G2. There is one problem I can't quite figure out, though: after grub comes up, and I press enter on any kernel to boot, the screen goes ...
1
vote
1answer
34 views
Linux setup compatibility
I want to setup a Linux environment, but I want the system to be bootable in two or more computer systems with different sets of hardware.
Can Linux provide that level of hardware abstraction given ...
1
vote
0answers
19 views
bcache not working as expected with ramdisk as cache device
I was trying out bcache but i don't have an SSD so wanted to use free memory as a substitute. As ramdisk is listed in /proc/devices as block device i assumed this would work OK but with below simple ...
0
votes
1answer
15 views
Abrupt Loss of Brightness Control
So I've had an openSUSE 13.2 (kernel 3.16.7-29) installation running on an Acer Aspire S7-392 for well over a year and have no problems until Sunday. I can't recall if I did an update or what, but I ...
0
votes
0answers
28 views
What's different between logical block and physical block?
I know the logical block is viewed by kernel, and physical block is viewed by disk controller.
Then, Where the file system like ext3's block is related? Is this logical or physical?
I think file ...
2
votes
0answers
32 views
How to detect rootkit linux kernel module based?
I found this small rootkit source code implemented as a Linux kernel module.
https://github.com/mfontanini/Programs-Scripts/tree/master/rootkit
Basically, as you can see, it changes the ...
0
votes
1answer
30 views
How to capture my screen video stream?
I try to capture the output of my gpu, the video flux of my desktop, to stream it on another computer. I'm working on a project like a remote control terminal so I can't have any latency.
I have ...
1
vote
2answers
58 views
what means 'processor execution level'?
I'm reading about Unix in a book "The design of UNIX operating system".
But, in the text middle of process state (e.g wakeup, interrupt), there is term 'raise processor execution level'.
What does ...
1
vote
1answer
19 views
Block device disappears after suspend-resume
After few suspend/resume cycles one of my hdd disappears from the list of devices, here is part of dmesg output that seems to be related to issue:
[ 450.005310] sd 5:0:0:0: [sdc] Starting disk
[ ...
1
vote
0answers
36 views
Error booting kernel 4.5.0-rc1 on Encrypted HDD
I cloned the Git tree of the mainline Linux Kernel and compiled it(version 4.5.0-rc1).
After compiling with default configuration (make defconfig) I installed it.
In the grub menu I can select this ...
-1
votes
0answers
34 views
C/Unix: How to extract the bits from st_mode? [migrated]
I am a beginner to Unix programming and C and I have two questions regarding the stat struc and its field st_mode:
When accessing the st_mode field as below, what type of number is returned ( octal, ...
2
votes
2answers
65 views
Module vfat fails to load (I've tried the obvious fixes)
The module vfat doesn't load on boot, and attempts to force the issue with a modprobe vfat produce the error
modprobe: ERROR: could not insert 'vfat': Unknown symbol in module, or unknown parameter ...
3
votes
1answer
60 views
How does linux load firmeware for built-in driver modules
I've learned that the firmware-subsystem uses udevd to copy a firmware to the created sysfs 'data' entry.
But how does this work in case of a built-in driver module where udevd hasn't started yet?
...
3
votes
0answers
40 views
FIPS mode, signature verification failed
I am building a kernel with FIPS mode on. I followed most of the procedures described on Red Hat documentation here.
I also created a hmac signed .vmlinuz file.
After installing dracut-fips and ...
0
votes
0answers
11 views
RAPL PMU detected, API unit is 2^-32, 4 fixed counters 655360 ms ovfl timer
I compiled my own kernel (version 4.1.5) using the commands:
#emerge --ask sys-kernel/genkernel
#genkernel all
And then I installed grub2 using these commands:
#emerge --ask sys-boot/grub
...
3
votes
1answer
33 views
How to dump the dmesg AKA Kernel logs to a single .txt file from the kernel boot?
I am trying to understand the SATA Host-Device Communication and for that I have put a lot of debug messages in the kernel driver code.
Now messages are in such a huge amount that I am not able to see ...
0
votes
0answers
53 views
Manually move kernel image to /boot directory
I have compiled my own kernel on Gentoo (following the handbook) and then I have moved the bzImage to /boot/vmlinuz-4.0.5. But when I boot the system I get the Grub2 shell. What am I doing wrong?
...
1
vote
1answer
58 views
Linux file system corruption due to improper shutdown (fs ext4)?
I have been managing many Linux servers, It is very easy to play with Linux servers than any other OS. But Sometime I encounter a problem with Linux OS is that, The file system corruption. This ...
3
votes
3answers
43 views
kernel configs and dependencies
When a particular kernel config is turned on, e.g.
CONFIG_CRYPTO_FIPS=y
a bunch of other dependencies (CONFIG_XXX_YYYY) get turned on during compilation. Is there a way to know all the dependencies ...
