modunload Hangs in modunload_begin()

(Doc ID 1609066.1)

Last updated on JULY 29, 2016

Applies to:

Solaris Operating System - Version 8.0 to 11.2 [Release 8.0 to 11.0]
Solaris Operating System - Version 11.3 to 11.3 [Release 11.0]
Information in this document applies to any platform.


Under certain circumstances the kernel requires its configuration to be consistent and unchanging. Most of these circumstances only persist for very short periods of time and cause no measurable delay in unloading a module, however one possibility can cause modunload to never finish.

The modunload thread will have a stack similar to this:



Most bundled drivers dynamically update their configuration based on events or configuration commands. However, in certain configuration, usually with 3rd party drivers, it may be necessary to unload a module directly or via update_drv. One known driver is emcp under Solaris 11, when adding new disks.


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