Hello,
the log is fairly generic. Here is a breakdown of what could be going on. If you are lucky, it is just a glitch, and it does not happen again. If it does happen again, it could be a software or a hardware issue. The 2921 is end of support, so the latest IOS you can download is the 15.7.3M8 release, which you are already running. Unfortunately, bus errors also can be hardware-related, in that case, your router is broken. How old is the router ?
The log message you provided indicates that the Cisco router experienced a bus error, leading to a system reload. Here is a breakdown of the components of the log message:
cisco router reload reason: This part of the message indicates that the router is reloading (restarting) due to a specific reason.
bus error: A bus error occurs when the router's central processing unit (CPU) encounters an invalid memory access on the system bus. This could be caused by a hardware or software issue.
at PC 0xB0D0B0D: The program counter (PC) is a register that holds the memory address of the instruction being executed. In this case, the PC value at the time of the bus error is 0xB0D0B0D.
address 0x0: The memory address 0x0 (zero) indicates that the error occurred at address zero, which is typically a null or uninitialized pointer.
The most common causes of bus errors include:
Hardware Issues: Faulty hardware components, such as RAM or other memory-related components, can cause bus errors.
Software Bugs: Bugs or software defects in the router's operating system (IOS) or running applications may lead to memory access violations.
Configuration Issues: Improper configuration settings may cause the router to access memory inappropriately.
To troubleshoot and resolve the issue, consider the following steps:
Upgrade the router's IOS to the latest stable release.
Check for any hardware issues, such as faulty RAM or other components.
Review the router's configuration for any misconfigurations.
Analyze crash dump information, if available, to identify the cause more precisely.
If you have access to Cisco support resources, consider reaching out to Cisco TAC (Technical Assistance Center) for further assistance in diagnosing and resolving the bus error issue.
