I was using a small Linux distro that was running X11 with JWM as its window manager. I was browsing a directory when all of a sudden the mouse froze and the keyboard became unresponsive. The caps lock and scroll lock lights are flashing.

What does this mean... and is there anything I can do about it?

  • Is there anything else you can tell us about the environment? – Steven D Nov 8 '10 at 3:06
  • @Steven: The distro is quite old - PuppyLinux 1.06 - and the computer is even older - an old Pentium MMX running at 200MHz. – Nathan Osman Nov 8 '10 at 6:33

The kernel has crashed your pc, the reason could be anything...

Good question is how you collect the crash data, so you know what crashed it.

But the only thing to do is to reboot the pc.

  • 2
    It magic sysrq support is compiled into the kernel you may be able to use some of those features before rebooting. – camh Nov 8 '10 at 9:52

It looks like lots of people are finding this via Google and the accepted answer isn't particularly precise, so I'll post my own answer.

Flashing caps lock and scroll lock lights signal a kernel panic. This means that the Linux kernel has experienced an unrecoverable error and cannot continue, a condition equivalent to a Stop error ("BSOD" or "blue screen") on Windows. However, because the Linux kernel is only able to directly output text on a console, it cannot signal a panic on the screen when the X server is running. As such, it blinks the Caps Lock and Scroll Lock lights on the keyboard continuously to indicate that the system has crashed.

A kernel panic can occur for a wide variety of reasons, ranging from hardware problems to faulty drivers to filesystem corruption. Your system log may contain more information; however, systemd-based distributions may not be able to write the information to disk because buffers are not synced on a panic (to prevent data corruption in the event the panic is caused by a filesystem bug). To diagnose a panic, a feature called kdump is available which uses a second Linux kernel running in a reserved region of memory to save a core dump of the failed kernel for analysis.

  • 2
    Instead of BSOD, we get BKOD (Blinky Keyboard of Death). – woot May 10 '19 at 21:13
  • Another way to capture the kernel panic output, provided the system has a serial port and you have something you can leave connected to it all the time to capture it. is to set up a serial console -- tldp.org/HOWTO/Remote-Serial-Console-HOWTO/… – rakslice May 15 '19 at 10:00

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