In the technote's I/O-wait scenario, the CCM core backtrace showed CallManager unable to process signals, which Cisco describes as possibly due to CPU or a blocked function.
Checked 2026-10-02
CallManager unable to process signals. This may be due to CPU or blocked function.
- Vendor
- Cisco
- Product
- Cisco Unified Communications Manager
- Subsystem
- core dumps
- Deployment
- on-premises
- Region
- not restricted
- Release range
- not stated; technote dated 2015
- Checked
- 2026-10-02
Sources
- CUCM Common Problems on UCS Platform: Core, High CPU - I/O, Hung State — Cisco Systems · tier 2 current vendor documentation · Scenario 1: High CPU Utilization Due to I/O Wait Issue > Verification (backtrace)
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting high CPU and service crashes in Unified CM: source note cucm-high-cpu-troubleshooting-ccm-core-signals-backtrace. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-high-cpu-troubleshooting-ccm-core-signals-backtrace
BibTeX
@misc{warmtransfer-claim-cucm-high-cpu-troubleshooting-ccm-core-signals-backtrace,
title = {Troubleshooting high CPU and service crashes in Unified CM: source note cucm-high-cpu-troubleshooting-ccm-core-signals-backtrace},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-high-cpu-troubleshooting-ccm-core-signals-backtrace},
note = {Source note cucm-high-cpu-troubleshooting-ccm-core-signals-backtrace, checked 2026-10-02}
}