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Diffstat (limited to 'Documentation/admin-guide/sysrq.rst')
| -rw-r--r-- | Documentation/admin-guide/sysrq.rst | 31 |
1 files changed, 22 insertions, 9 deletions
diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst index e6424d8c5846..2f2e5bd440f9 100644 --- a/Documentation/admin-guide/sysrq.rst +++ b/Documentation/admin-guide/sysrq.rst @@ -72,13 +72,24 @@ On PowerPC On other If you know of the key combos for other architectures, please - let me know so I can add them to this section. + submit a patch to be included in this section. On all - Write a character to /proc/sysrq-trigger. e.g.:: + Write a single character to /proc/sysrq-trigger. + Only the first character is processed, the rest of the string is + ignored. However, it is not recommended to write any extra characters + as the behavior is undefined and might change in the future versions. + E.g.:: echo t > /proc/sysrq-trigger + Alternatively, write multiple characters prepended by underscore. + This way, all characters will be processed. E.g.:: + + echo _reisub > /proc/sysrq-trigger + +The :kbd:`<command key>` is case sensitive. + What are the 'command' keys? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -88,8 +99,8 @@ Command Function ``b`` Will immediately reboot the system without syncing or unmounting your disks. -``c`` Will perform a system crash by a NULL pointer dereference. - A crashdump will be taken if configured. +``c`` Will perform a system crash and a crashdump will be taken + if configured. ``d`` Shows all locks that are held. @@ -136,7 +147,7 @@ Command Function ``v`` Forcefully restores framebuffer console ``v`` Causes ETM buffer dump [ARM-specific] -``w`` Dumps tasks that are in uninterruptable (blocked) state. +``w`` Dumps tasks that are in uninterruptible (blocked) state. ``x`` Used by xmon interface on ppc/powerpc platforms. Show global PMU Registers on sparc64. @@ -203,10 +214,12 @@ frozen (probably root) filesystem via the FIFREEZE ioctl. Sometimes SysRq seems to get 'stuck' after using it, what can I do? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -That happens to me, also. I've found that tapping shift, alt, and control -on both sides of the keyboard, and hitting an invalid sysrq sequence again -will fix the problem. (i.e., something like :kbd:`alt-sysrq-z`). Switching to -another virtual console (:kbd:`ALT+Fn`) and then back again should also help. +When this happens, try tapping shift, alt and control on both sides of the +keyboard, and hitting an invalid sysrq sequence again. (i.e., something like +:kbd:`alt-sysrq-z`). + +Switching to another virtual console (:kbd:`ALT+Fn`) and then back again +should also help. I hit SysRq, but nothing seems to happen, what's wrong? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |