From 5e7388aad420937e52e2437b7d3ee8ea7a07a26a Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Wed, 11 Feb 2009 08:59:13 +1300 Subject: [PATCH] proc.5: Add description of /proc/sys/kernel/sysrq Reported by: Goerghe Cosorea Signed-off-by: Michael Kerrisk --- man5/proc.5 | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/man5/proc.5 b/man5/proc.5 index 6c8abdebf..a6975dd46 100644 --- a/man5/proc.5 +++ b/man5/proc.5 @@ -58,7 +58,7 @@ .\" to see what information could be imported from that file .\" into this file. .\" -.TH PROC 5 2009-02-03 "Linux" "Linux Programmer's Manual" +.TH PROC 5 2009-02-12 "Linux" "Linux Programmer's Manual" .SH NAME proc \- process information pseudo-file system .SH DESCRIPTION @@ -2291,6 +2291,33 @@ This file specifies the system-wide maximum number of System V shared memory segments that can be created. .TP +.I /proc/sys/kernel/sysrq +This file controls the functions allowed to be invoked by the SysRq key. +By default, +the file contains 1 meaning that every possible SysRq request is allowed +(in older kernel versionsm, SysRq was disabled by default, +and you were required to specifically enable it at run-time, +but this is not the case any more). +Possible values in this file are: + + 0 - disable sysrq completely + 1 - enable all functions of sysrq + >1 - bitmask of allowed sysrq functions, as follows: + 2 - enable control of console logging level + 4 - enable control of keyboard (SAK, unraw) + 8 - enable debugging dumps of processes etc. + 16 - enable sync command + 32 - enable remount read-only + 64 - enable signalling of processes (term, kill, oom-kill) + 128 - allow reboot/poweroff + 256 - allow nicing of all real-time tasks + +This file is only present if the +.B CONFIG_MAGIG_SYSRQ +kernel configuration option is enabled. +For further details see the kernel source file +.IR Documentation/sysrq.txt . +.TP .I /proc/sys/kernel/version This file contains a string like: