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Questions tagged [linux-kernel]

The Linux kernel is the operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software.

The Linux kernel is the operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software.

The Linux kernel is released under the GNU General Public License version 2 (GPLv2) (plus some firmware images with various non-free licenses[citation needed]), and is developed by contributors worldwide. Day-to-day development discussions take place on the Linux kernel mailing list.

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How to view linux kernel logs live?

I have a kernel module logging input of some sensor while I work with it. I want to see if there is a command that outputs /var/log/messages (for example) but waits for more logs to come. That is, some program like dmesg except that it stays on and…
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How to compile the kernel with debug symbols?

I've already finishing compiling the kernel from source, but how to compile it with debug symbols,what additional steps to I need to take?
yum
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Our embedded linux system won't recognize a USB Device if it is plugged in before powerup. Suggestions?

We are developing on a small embedded device. This device us a gumstix overo board running OpenEmbedded linux. We have our development almost completely done, and have run into the strangest of bugs that we can't figure out. We have a USB Device…
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How to get the latest kernel package on AWS EC2

I manage some EC2 instances running Amazon Linux (not sure what version), which need security patches. A lot of software was patched well, but we have stuck on the kernel upgrade. We are unable to use the latest kernel version as we preferred. What…
WICHPONG KAO-IAN
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Why 224.0.0.1 traffic is filtered by Linux hosts?

When sending an ICMPv4 echo request to a destination address like 224.0.0.1, it is ignored by Linux hosts receiving the request. The destination MAC address used is 01:00:5e:00:00:01. The only way to have those Linux hosts answering is to set the…
djoproject
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Debugging kmalloc-64 slab allocations / memory leak

I have two virtual servers that are configured very similarly: Debian bullseye (testing), 5.6.0 kernel, 512 MB RAM. They're both running a similar workload: MySQL, PowerDNS, WireGuard, dnstools.ws worker, and Netdata for monitoring. On just one of…
Daniel Lo Nigro
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ZFS datasets no longer automatically mount on reboot after system upgrade

I have an Arch linux ZFS backup system which wasn't updated for a long time because it was working perfectly and there was no reason to bother. After a recent upgrade, though, my ZFS datasets are no longer automatically mounted when I reboot. …
pgoetz
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Misunderstanding about Page Cache and dirty_background_bytes

I've been looking at this for a while now and things aren't lining up with my expectations, but I don't know if it's because something is off, or if my expectations are wrong. So, I've got a system with over 100GB of RAM, and I've set my…
psycotica0
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Why can't my Linux kernel reclaim its slab memory?

I have a system that suffered from ever-increasing memory usage until it hit the point where it was hitting swap even for mundane things and consequently becoming pretty unresponsive. The culprit appears to have been kernel-allocated memory, but…
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Why sudden kernel timestamp jump?

We have several HP ProLiant BL460c Gen8, BIOS I31 06/01/2015 servers running CentOS kernel 2.6.32-358.2.1 and are observing a sudden spike in kernel log timestamp. This is from /var/log/messages: May 19 05:31:58 NWBLWICZVIS-A-VZ-GVS2-01 kernel: [ …
pdp
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Linux no modify time (nomtime)

Is there a way to disable the mtime of an filesystem? There is an Filesystem independend noatime Option, but no "nomtime". Also in the Filesystem specific documentation for ext4 and/or btrfs i couldn't find this. Does this exist?
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kswap using 100% of CPU even with 100GB+ of RAM available

I'm running a Centos 7 ESXi VM with almost 300GB of RAM and 24 vCPUs. The average load is 3 and apps almost never use more than 150GB of RAM. The rest of the available memory is used by Linux for cache. The issue is that when the cache fills up…
Fernando
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'BUG: unable to handle kernel NULL pointer dereference at' on Google Compute Engine

On a semi-regular basis, I've seen GCE instances freezing with the following error message (from the serial console): g[1375589.784755] BUG: unable to handle kernel NULL pointer dereference at 0000000000000078 g[1375589.786206] IP:…
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Why does strace return so many execve calls with ENOENT return code?

I wanted to use strace to see what was happening when I do `hadoop fs -ls ', so I ran the command: strace -f -e trace=execve hadoop fs -ls /stg which resulted in a lot of output like this: [pid 187050]…
jcm
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ext3/ext4 physical block size view

I'm using a suse 11 server with xfs and using "xfs_info /srv" command i seen this. xfs_info /srv/ meta-data=/dev/mapper/vg01-srvvol isize=256 agcount=38, agsize=1964032 blks = sectsz=512 attr=2 data = …
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