illumos gate

When performing the dlmgmt_zonehalt door command, a global write lock is held across a system call. The system call then performs a door_upcall back to the dlmgmtd process which tries to acquire a read lock.

Which results in a deadlock. But only occasionally.

I have a core dump of the dlmgmt process, but it is over 4 Mb so I can't attach it.

Attached is a set of mdv commands I ran to debug the issue.