[Linux][Kerne][Tips] 在 minicom 下送出 SysRq

除了 Linux kernel 要加上 SysRq 的 Function 以外,

按 ctrl+a f 就是送出 break key.
這要配合 Command Key 使用

*  What are the 'command' keys?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'b'     - Will immediately reboot the system without syncing or unmounting
          your disks.

'c' - Will perform a kexec reboot in order to take a crashdump.

'd' - Shows all locks that are held.

'e'     - Send a SIGTERM to all processes, except for init.

'f' - Will call oom_kill to kill a memory hog process.

'g' - Used by kgdb on ppc and sh platforms.

'h'     - Will display help (actually any other key than those listed
          above will display help. but 'h' is easy to remember :-)

'i'     - Send a SIGKILL to all processes, except for init.

'k'     - Secure Access Key (SAK) Kills all programs on the current virtual
          console. NOTE: See important comments below in SAK section.

'm'     - Will dump current memory info to your console.

'n' - Used to make RT tasks nice-able

'o'     - Will shut your system off (if configured and supported).

'p'     - Will dump the current registers and flags to your console.

'q'     - Will dump a list of all running timers.

'r'     - Turns off keyboard raw mode and sets it to XLATE.

's'     - Will attempt to sync all mounted filesystems.

't'     - Will dump a list of current tasks and their information to your
          console.

'u'     - Will attempt to remount all mounted filesystems read-only.

'v' - Dumps Voyager SMP processor info to your console.

'w' - Dumps tasks that are in uninterruptable (blocked) state.

'x' - Used by xmon interface on ppc/powerpc platforms.

'0'-'9' - Sets the console log level, controlling which kernel messages
          will be printed to your console. ('0', for example would make
          it so that only emergency messages like PANICs or OOPSes would
          make it to your console.)

例如要 dump memory info,
就按 ctrl+a f m

SysRq 拿來對付不知名的 hang up 還算是有用的. 以上的列表不是每個平台都完全支援所有的 Command, 要試一下

ref.
   Linux kernel Documentation/sysrq.txt