Debugging Commands - Cisco 2611 - Router - EN User Manual

Debugging Commands

Most debugging commands are functional only when Cisco IOS software has crashed or is
aborted. If you enter a debugging command and Cisco IOS crash information is not
available, the following error message appears:
"xxx: kernel context state is invalid, can not proceed."
•
stack or k—Produce a stack trace.
•
context—Display processor context.
•
frame—Display an individual stack frame.
•
sysret—Display return information from the last booted system image. This
information includes the reason for terminating the image, a stack dump of up to eight
frames, and, if an exception is involved, the address where the exception occurred. For
example:
rommon 8 > sysret
System Return Info:
count: 19,
pc:0x802b1040,
Stack Trace:
FP: 0x80908398, PC: 0x802b102c
FP: 0x809083b0, PC: 0x802b0b88
FP: 0x809083d8, PC: 0x8017039c
FP: 0x809083e8, PC: 0x8016f764
Configuration Register Commands
The virtual configuration register resides in NVRAM. You can display or modify the virtual
configuration register from either the ROM monitor or the operating system software.
To change the virtual configuration register from the ROM monitor, enter confreg by itself
for menu mode, or enter the new value of the register in hexadecimal.
•
confreg [hexnum]—Change the virtual configuration register to the value specified. The
value is always interpreted as hexadecimal. Entering confreg without an argument
displays the contents of the virtual configuration register and prompts you to alter the
contents by describing the meaning of each bit.
reason: a SegV exception
error address: 0x802b1040
Debugging Commands
Using the ROM Monitor C-7