crash(8v) — RISC
Name
crash − what happens when the system crashes
Description
This section explains what happens when the system crashes and shows how to analyze crash dumps.
When the system crashes voluntarily it prints a message on the console in the form:
panic: explanation
The system takes a dump on a mass storage peripheral device or the network, and then invokes an automatic reboot procedure as described in reboot(.). Unless there is some unexpected inconsistency in the state of the file systems due to hardware or software failure, the system then resumes multi-user operations. If auto-reboot is disabled, the system halts at this point.
The system has a large number of internal consistency checks; if one of these fails, it prints a short message indicating which one failed.
The most common cause of system failures is hardware failure. In all cases there is the possibility that hardware or software error produced the message in some unexpected way. These messages are the ones you are likely to encounter:
IO err in push
hard IO err in swap
The system encountered an error when trying to write to the paging device or an error in reading critical information from a disk drive. Fix your disk if it is broken or unreliable.
timeout table overflow
Due to the current data structure, running out of entries causes a crash. If this happens, make the timeout table bigger.
Exception Condition
An unexpected system error has occurred. The exception types are as follows:
| Mnemonic@Description | |
| INT@External interrupt | |
| MOD@TLB modification exception | |
| TLBL@TLB miss exception (load or instruction fetch) | |
| TLBS@TLB miss exception (store) | |
| AdEL@Address error exception (load or instruction fetch) | |
| AdES@Address error exception (store) | |
| IBE@Bus error exception (for an instruction fetch) | |
| DBE@Bus error exception (for a data load or store) | |
| Sys@Sys call exception | |
| Bp@Breakpoint exception | |
| CpU@Coprocessor unusable exception | |
| Ovf@Arithmetic overflow exception |
KSP not valid
This indicates either a problem in the system or failing hardware.
init died
The system initialization process has exited. The only solution is the automatic reboot procedure described in reboot(.). Until this is done, new users cannot log in.
When the system crashes, it attempts to write an image of memory into the back end of the primary swap area. After the system is rebooted, the program savecore() runs and preserves a copy of this core image and the current system in a specified directory for later access. See savecore() for details.
To analyze a dump, you should begin by running dbx() with the −k flag on the core dump.