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Diffstat (limited to 'Documentation/admin-guide/sysrq.rst')
| -rw-r--r-- | Documentation/admin-guide/sysrq.rst | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst index 2f2e5bd440f9..a85b3384d1e7 100644 --- a/Documentation/admin-guide/sysrq.rst +++ b/Documentation/admin-guide/sysrq.rst @@ -161,6 +161,8 @@ Command Function 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.) + +``R`` Replay the kernel log messages on consoles. =========== =================================================================== Okay, so what can I use them for? @@ -211,6 +213,13 @@ processes. "just thaw ``it(j)``" is useful if your system becomes unresponsive due to a frozen (probably root) filesystem via the FIFREEZE ioctl. +``Replay logs(R)`` is useful to view the kernel log messages when system is hung +or you are not able to use dmesg command to view the messages in printk buffer. +User may have to press the key combination multiple times if console system is +busy. If it is completely locked up, then messages won't be printed. Output +messages depend on current console loglevel, which can be modified using +sysrq[0-9] (see above). + Sometimes SysRq seems to get 'stuck' after using it, what can I do? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |