Bug ID 2459393: TMM crash when PEM policy tcl-filter uses PEM::session info attr on multi-blade system

Last Modified: Aug 31, 2026

Affected Product(s):
BIG-IP PEM(all modules)

Known Affected Versions:
17.5.1.5, 17.5.1.6, 17.5.1.8

Opened: Aug 14, 2026

Severity: 3-Major

Symptoms

- TMM generates a SIGSEGV core file and restarts - The log contains the message: PEM: spm_tcl_filter_find_match: <policy_name> suspending iRule command not supported shortly before the crash

Impact

TMM crashes and restarts, causing traffic disruption. Multiple TMMs may core in quick succession during cluster topology changes

Conditions

- BIG-IP PEM provisioned on a multi-blade VELOS system - A PEM policy uses an inline tcl-filter containing an async-capable command such as PEM::session info attr [IP::client_addr] <attribute_name> - A cluster membership change occurs (blade join or leave), causing previously local PEM session lookups to become non-local (asynchronous)

Workaround

Move the PEM::session info attr command out of the PEM policy inline tcl-filter and into a standard iRule where asynchronous command suspension is supported. The tcl-filter execution context does not support suspending/async commands

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips