O'Reilly logo

Panic! UNIX® System Crash Dump Analysis by Kimberley Brown, Chris Drake

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 27. Watchdog Resets

Sometimes a system will die with a “watchdog reset” message on the console and will drop into the boot PROM (or possibly reboot automatically). It’s not a panic: The system is no longer in control, it’s not dumping memory to disk, and the CPU has done a reset.

What is a watchdog?

Watchdog resets usually indicate a software problem, although the root cause may be hardware related. The immediate cause is a trap, like a page fault, that occurs in the middle of handling another trap. The kernel processes a trap with the Enable Traps bit in the Processor Status Register reset (turned off), which prevents the CPU from accepting another trap until the initial processing of the first one is complete. This means that another trap ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required