Summary:	ASTERISK-15614: [patch] chan_sip does not decrease module refcount on deferred BYE
Reporter:	Ben Winslow (rain)	Labels:
Date Opened:	2010-02-11 14:35:26.000-0600	Date Closed:	2010-06-22 12:37:26
Priority:	Minor	Regression?	No
Status:	Closed/Complete	Components:	Channels/chan_sip/General
Versions:		Frequency of Occurrence
Related Issues:
Environment:		Attachments:	( 0) chan_sip-unref-fix.diff
Description:	When sip_hangup clears a channel with SIP_DEFER_BYE_ON_TRANSFER set, it will return without calling ast_module_unref().  This causes the use counter for chan_sip to increase over time, making it impossible to unload the module without restarting Asterisk. The attached patch calls ast_module_unref() immediately before returning in the deferred BYE case.  I believe this is safe, because the SIP dialog involved will still be freed when the containing AO2 object's refcount hits 0 as part of module_unload. ****** STEPS TO REPRODUCE ****** Observe chan_sip's use count after a call transfer that causes SIP_DEFER_BYE_ON_TRANSFER to be set. ****** ADDITIONAL INFORMATION ****** This bug exists all the way back to 1.4.x, and I believe the same fix is safe there without leaking memory; however, I haven't looked at that code as hard so I'm not 100% sure.
Comments:	By: Leif Madsen (lmadsen) 2010-02-17 13:34:21.000-0600 Thanks for the contribution! By: Ben Winslow (rain) 2010-05-04 14:34:29 I've been testing this patch for a few months now, and although I haven't had to unload chan_sip many times during that period, I've had no issues and my refcount currently matches the number of SIP channels in use. By: Digium Subversion (svnbot) 2010-06-22 12:31:57 Repository: asterisk Revision: 271902 U   branches/1.4/channels/chan_sip.c ------------------------------------------------------------------------ r271902 | mnicholson | 2010-06-22 12:31:56 -0500 (Tue, 22 Jun 2010) | 8 lines Decrease the module ref count in sip_hangup when SIP_DEFER_BYE_ON_TRANSFER is set.  This is necessary to keep the ref count correct. (closes issue ASTERISK-15614) Reported by: rain Patches:      chan_sip-unref-fix.diff uploaded by rain (license 327) Tested by: rain ------------------------------------------------------------------------ http://svn.digium.com/view/asterisk?view=rev&revision=271902 By: Digium Subversion (svnbot) 2010-06-22 12:32:37 Repository: asterisk Revision: 271902 U   branches/1.4/channels/chan_sip.c ------------------------------------------------------------------------ r271902 | mnicholson | 2010-06-22 12:31:57 -0500 (Tue, 22 Jun 2010) | 8 lines Decrease the module ref count in sip_hangup when SIP_DEFER_BYE_ON_TRANSFER is set.  This is necessary to keep the ref count correct. (closes issue ASTERISK-15614) Reported by: rain Patches:      chan_sip-unref-fix.diff uploaded by rain (license 327) (modified) Tested by: rain ------------------------------------------------------------------------ http://svn.digium.com/view/asterisk?view=rev&revision=271902 By: Digium Subversion (svnbot) 2010-06-22 12:35:17 Repository: asterisk Revision: 271903 _U  trunk/ U   trunk/channels/chan_sip.c ------------------------------------------------------------------------ r271903 | mnicholson | 2010-06-22 12:35:16 -0500 (Tue, 22 Jun 2010) | 15 lines Merged revisions 271902 via svnmerge from https://origsvn.digium.com/svn/asterisk/branches/1.4 ........  r271902 | mnicholson | 2010-06-22 12:31:57 -0500 (Tue, 22 Jun 2010) | 8 lines    Decrease the module ref count in sip_hangup when SIP_DEFER_BYE_ON_TRANSFER is set.  This is necessary to keep the ref count correct.    (closes issue ASTERISK-15614)  Reported by: rain  Patches:        chan_sip-unref-fix.diff uploaded by rain (license 327) (modified)  Tested by: rain ........ ------------------------------------------------------------------------ http://svn.digium.com/view/asterisk?view=rev&revision=271903 By: Digium Subversion (svnbot) 2010-06-22 12:37:26 Repository: asterisk Revision: 271904 _U  branches/1.6.2/ U   branches/1.6.2/channels/chan_sip.c ------------------------------------------------------------------------ r271904 | mnicholson | 2010-06-22 12:37:25 -0500 (Tue, 22 Jun 2010) | 22 lines Merged revisions 271903 via svnmerge from https://origsvn.digium.com/svn/asterisk/trunk ................  r271903 | mnicholson | 2010-06-22 12:35:17 -0500 (Tue, 22 Jun 2010) | 15 lines    Merged revisions 271902 via svnmerge from  https://origsvn.digium.com/svn/asterisk/branches/1.4    ........    r271902 | mnicholson | 2010-06-22 12:31:57 -0500 (Tue, 22 Jun 2010) | 8 lines        Decrease the module ref count in sip_hangup when SIP_DEFER_BYE_ON_TRANSFER is set.  This is necessary to keep the ref count correct.        (closes issue ASTERISK-15614)    Reported by: rain    Patches:          chan_sip-unref-fix.diff uploaded by rain (license 327) (modified)    Tested by: rain  ........ ................ ------------------------------------------------------------------------ http://svn.digium.com/view/asterisk?view=rev&revision=271904