• Diff for "KernelFAQ"

Kernel > FAQ

Newer Kernel ?

Why would I install a new kernel?

It is often not necessary since the default kernel shipped with Debian handles most configurations. However, it is useful to compile a new kernel in order to:

• Handle special hardware needs, or hardware conflicts with the pre-supplied kernels.

• Optimize the kernel by removing useless drivers to speed up boot time (Do you really need it?)

• Use options of the kernel which are not supported by the default kernel (see reasons).

You have two options to install a new kernel : you can install one of the precompiled kernels provided by Debian/GNU Linux or build the kernel yourself.

Installing linux image

This is explained in HowToUpgradeKernel.

Building my own kernel

This is explained in HowToRebuildAnOfficialDebianKernelPackage.

Troubleshooting/Debugging

Kernel Oops

The 'oops' refers to the message printed by the Linux kernel when an unforseen condition occurs. Such incidents should be reported to the Linux kernel developers. Information on how to do so comes with the Linux kernel sources. You may consider to install the Debian package 'kerneloops' to automate the reporting (see ?Kernel/Oops).

Information

Misc FAQ

What's my current kernel?

Use the command uname. For example : uname -r which prints 2.6.26-1-686 (so the package name is linux-image-$(uname -r)).

Which package does it comes from?

Usually, this command will work : dpkg -p linux-image-$(uname -r).

Where is the kernel configuration file?

The kernel configuration file of Debian Official kernel are available in /boot, named after the kernel release, like /boot/config-2.6.18-6-486, or /boot/config-$(uname -r).

All the kernel configuration files, which were used to build the official Debian's binary kernel images from the linux-2.6 source package are available from http://merkel.debian.org/~jurij/.

Kernel Source ? : See dpkg -l 'linux-source*' for available source packages, and KernelGit for development trees.

Kernel Headers ??

see KernelHeaders.

Patches included in the Debian Linux kernel

http://svn.debian.org/wsvn/kernel/dists/trunk/linux-2.6/debian/patches/?rev=0&sc=0

Firmware not included

see KernelFirmwareLicensing?

New features in Lenny

Summary of new kernel features in Lenny

• .. to be written

kernelnewbies.org has summaries of new features in kernels :

2.6.26

2.6.26 adds support for read-only bind mounts, x86 PAT (Page Attribute Tables), PCI Express ASPM (Active State Power Management), ports of KVM to IA64, S390 and PPC, other KVM improvements including basic paravirtualization support, preliminary support of the future 802.11s wireless mesh standard, much improved webcam support thanks to a driver for UVC devices, a built-in memory tester, a kernel debugger, BDI statistics and parameters exposure in /sys/class/bdi, a new /proc/PID/mountinfo file for more accurate information about mounts, per-process securebits, device white-list for containers users, support for the Playstation3 and OLPC, some new drivers and many small improvements. more on http://kernelnewbies.org/Linux_2_6_26.

2.6.25

2.6.25 includes support of a new architecture (MN10300/AM33) and the widely used Orion ?SoCs, a new interface for more accurate measurement of process memory usage, a 'memory resource controller' for controlling the memory usage of groups of processes, realtime group scheduling, a tool for measuring high latencies called latencytop , ACPI thermal regulation, timer event notifications through file descriptors, an alternative MAC security framework called SMACK, a ext4 update, BRK and PIE-executable address space randomization, RCU preemption support, FIFO spinlocks in x86, EFI support in x86-64, a new network protocol called CAN, initial ATI r500 DRI/DRM support, the beginning of the end for tasks stuck in D state, improved device support and many other small improvements. more on http://kernelnewbies.org/Linux_2_6_25.

2.6.24

2.6.24 includes CPU "group scheduling", memory fragmentation avoidance, tickless support for x86-64/ppc and other architectures, many new wireless drivers and a new wireless configuration interface, SPI/SDIO MMC support, USB authorization, per-device dirty memory thresholds, support for PID and network namespaces, support for static probe markers, read-only bind mounts, SELinux performance improvements, SATA link power management and port multiplier support, Large Receive Offload in network devices, memory hot-remove support, a new framework for controlling the idle processor power management, CIFS ACLs support, many new drivers and many other features and fixes. more on http://kernelnewbies.org/Linux_2_6_24.

2.6.23

2.6.23 includes the new, better, fairer CFS process scheduler, a simpler read-ahead mechanism, the lguest 'Linux-on-Linux' paravirtualization hypervisor, XEN guest support, KVM smp guest support, variable process argument length, make SLUB the default slab allocator, SELinux protection for exploiting null dereferences using mmap, XFS and ext4 improvements, PPP over L2TP support, the 'lumpy' reclaim algorithm, a userspace driver framework, the O_CLOEXEC file descriptor flag, splice improvements, new fallocate() syscall, lock statistics, support for multiqueue network devices, various new drivers and many other minor features and fixes. more on http://kernelnewbies.org/Linux_2_6_23.

2.6.22

2.6.22 includes an optional, more SMP-friendly SLUB allocator ), new and much better wireless and firewire stacks, a new architecture called Blackfin, a LVM-for-flash-storage-devices called UBI, event notifications through file descriptors , the POSIX-draft utimensat() syscall, the 'TCP Illinois' and 'YeAH-TCP' congestion control algorithms, IPV6 Optimistic Duplicate Address Detection, AF_RXRPC socket support, relocatable x86-64 kernel support, improvements to the CFQ I/O scheduler, more process footprint information in /proc, various new drivers and many other improvements. more on http://kernelnewbies.org/Linux_2_6_22.

2.6.21

2.6.21 improves the virtualization features merged in 2.6.20 with VMI, a paravirtualization interface that will be used by Vmware (and maybe -probably not- Xen) software. KVM does get initial paravirtualization along with live migration and host suspend/resume support. 2.6.21 also gets a tickless idle loop mechanism called "Dynticks" , a feature built in top of "clockevents" which unifies the timer handling and brings true high-resolution timers. Other features are: bigger kernel command-line, optional ZONE_DMA; support for the PA SEMI PWRficient CPU, for a Cell-based "celleb" architecture from Toshiba, better PS3 support: support for NFS IPv6, IPv4 <-> IPv6 IPSEC tunneling support, UFS2 write support, kprobes for PPC32, kexec and oprofile for ARM, public key encryption for ecryptfs, Fcrypt and Camilla cipher algorithms, NAT port randomization, audit lockdown mode, many new drivers and many other small improvements.more on http://kernelnewbies.org/Linux_2_6_21.

2.6.20

With 2.6.20, Linux joins the virtualization trend. This release adds two virtualization implementations: A full-virtualization implementation that uses Intel/AMD hardware virtualization capabilities called KVM and a paravirtualization implementation that can be used by different hypervisors (Rusty's lguest; Xen and VMWare in the future, etc). This release also adds initial Sony Playstation 3 support, a fault injection debugging feature , UDP-lite support, better per-process IO accounting, relative atime, support for using swap files for suspend users, relocatable x86 kernel support for kdump users, small microoptimizations in x86 (sleazy FPU, regparm, support for the Processor Data Area, optimizations for the Core 2 platform), a generic HID layer, DEEPNAP power savings for PPC970, lockless radix-tree readside, shared pagetables for hugetbl, ARM support for the AT91 and iop13xx processors, full NAT for nf_conntrack and many other things.more on http://kernelnewbies.org/Linux_2_6_20.

2.6.19

Linux 2.6.19 includes the clustering GFS2 filesystem ; Ecryptfs the first experimental version of EXT4 (aimed at developers), support for the Atmel AVR32 architecture, sleepable RCU, improvements for NUMA-based systems, a "-o flush" mount option aimed at FAT-based hotpluggable media devices (mp3), physical CPU hotplug and memory hot-add in x86-64, support for compiling x86 kernels with the GCC stack protection, vectored async I/O , Netlabel subsystem, allow to disable compilation of the block layer, IDE Parallel-ATA drivers based in libata, Granular IPSec associations for use in MLS environments, add the Netlabel subsystem, Mobile IPv6 (RFC 3775), some new drivers, improved support for many already existing drivers, and many other things.more on http://kernelnewbies.org/Linux_2_6_19.

New features in Etch