[OpenSIPS-Devel] [OpenSIPS/opensips] 8e54f0: mid_registrar: Fix possible crash on shutdown

[Liviu Chircu]

  Branch: refs/heads/master
  Home:   https://github.com/OpenSIPS/opensips
  Commit: 8e54f04feba4f3071577831c7848ee16d674963c
      https://github.com/OpenSIPS/opensips/commit/8e54f04feba4f3071577831c7848ee16d674963c
  Author: Liviu Chircu <liviu at opensips.org>
  Date:   2019-11-13 (Wed, 13 Nov 2019)

  Changed paths:
    M modules/mid_registrar/save.c

  Log Message:
  -----------
  mid_registrar: Fix possible crash on shutdown

Since the TMCB_TRANS_DELETED callback _may get called after_ the module
destroy() phase, the udomain_t structure attached to the callback must
not be accessed anymore if OpenSIPS is shutting down, as the usrloc
module may have already freed most of its data structures.

Fixes #1641

(cherry picked from commit 1fbe9a66c57ea35eb73661c528d5a5dbc77f5858)