[FEATURE REQUEST] Enable SysRq by default

[Mikhail Novosyolov]

I propose to change the following kernel build options:
CONFIG_MAGIC_SYSRQ=y
CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE=0x1

Or write
kernel.sysrq = 1
to /etc/systl.d/99-sysctl.conf (/etc/sysctl.conf)

It will enable full SysRq, and the combination
alt+SysRq+R,F will force oom_killer to kill the process which is using the most memory. It helps greatly in cases of system freezes, especially when a browser tab uses too much memory.

And sometimes it causes swapping, and if the swapping device input/output is slow, it makes the system freeze for a long time due to processor scheduler being busy.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: linux-generic 4.13.0.16.17
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC2: user 1869 F.... pulseaudio
 /dev/snd/controlC1: user 1869 F.... pulseaudio
 /dev/snd/controlC0: user 1869 F.... pulseaudio
CurrentDesktop: XFCE
Date: Tue Oct 31 15:38:32 2017
HibernationDevice: RESUME=UUID=844fc9fb-509d-4dab-9ea5-a3d5142f76d8
InstallationDate: Installed on 2017-08-28 (64 days ago)
InstallationMedia: Xubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
MachineType: ASUS All Series
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-4.13.0-16-generic.efi.signed root=UUID=355fccdc-c430-43b5-929b-f38e35136c1c ro rootflags=subvol=@ quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.13.0-16-generic N/A
 linux-backports-modules-4.13.0-16-generic N/A
 linux-firmware 1.169
RfKill:

SourcePackage: linux
UpgradeStatus: Upgraded to artful on 2017-09-16 (44 days ago)
dmi.bios.date: 03/10/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0801
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: AM1I-A
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0801:bd03/10/2016:svnASUS:pnAllSeries:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnAM1I-A:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.family: ASUS MB
dmi.product.name: All Series
dmi.product.version: System Version
dmi.sys.vendor: ASUS

[Mikhail Novosyolov (mikhailnov)]

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/194676

[Mikhail Novosyolov (mikhailnov)]

Well, I agree that it is a security problem if the user is able to kill a process that he must not be able to kill...

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.