Link to this headingSysRq
Link to this headingDisable
Check Current SysRq Value:
0 - disable sysrq completely
1 - enable all functions of sysrq
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 signaling of processes (term, kill, oom-kill)
128 - allow reboot/poweroff
256 - allow nicing of all RT tasks
Temp Enable All SysRq settings:
Temp Disable All SysRq settings:
Persistent Enable all SysRq settings:
Link to this headingCommands
| Set the console log level, which controls the types of kernel messages that are output to the console | 0 - 9 |
| Immediately reboot the system, without unmounting or syncing filesystems | b |
| Perform a system crash. A crashdump will be taken if it is configured. | c |
| Display all currently held Locks (CONFIG_LOCKDEP kernel option is required) | d |
| Send the SIGTERM signal to all processes except init (PID 1) | e |
| Call oom_kill, which kills a process to alleviate an OOM condition | f |
| If the in-kernel debugger kdb is present, enter the debugger. | g |
| Any key which is not bound to a command should also perform this action | h |
| Send the SIGKILL signal to all processes except init | i |
| Forcibly "Just thaw it" – filesystems frozen by the FIFREEZE ioctl. | j |
| Kill all processes on the current virtual console (can kill X and SVGAlib programs, see below) | k |
| Shows a stack backtrace for all active CPUs. | l |
| Output current memory information to the console | m |
| Reset the nice level of all high-priority and real-time tasks | n |
| Output the current registers and flags to the console | p |
| Display all active high-resolution timers and clock sources. | q |
| Switch the keyboard from raw mode, used by programs such as X11 and SVGAlib, to XLATE mode | r |
| Output a list of current tasks and their information to the console | t |
| Remount all mounted filesystems in read-only mode | u |
| Forcefully restores framebuffer console. For ARM processors, cause ETM buffer dump instead. | v |
| Display list of blocked (D state) tasks | w |
| Used by xmon interface on PowerPC platforms. Dump all TLB entries on MIPS. | x |
| Show global CPU registers (SPARC-64 specific) | y |