From 0165c5f95aa058b0884f8dec8695237cb0bef186 Mon Sep 17 00:00:00 2001 From: Richard Mudgett Date: Fri, 3 Oct 2014 17:47:42 +0000 Subject: chan_pjsip: Fix deadlock when masquerading PJSIP channels. Performing a directed call pickup resulted in a deadlock when PJSIP channels were involved. A masquerade needs to hold onto the channel locks while it swaps channel information between the two channels involved in the masquerade. With PJSIP channels, the fixup routine needed to push a fixup task onto the PJSIP channel's serializer. Unfortunately, if the serializer was also processing a task that needed to lock the channel, you get deadlock. * Added a new control frame that is used to notify the channels that a masquerade is about to start and when it has completed. * Added the ability to query taskprocessors if the current thread is the taskprocessor thread. * Added the ability to suspend/unsuspend the PJSIP serializer thread so a masquerade could fixup the PJSIP channel without using the serializer. ASTERISK-24356 #close Reported by: rmudgett Review: https://reviewboard.asterisk.org/r/4034/ ........ Merged revisions 424471 from http://svn.asterisk.org/svn/asterisk/branches/12 ........ Merged revisions 424472 from http://svn.asterisk.org/svn/asterisk/branches/13 git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@424473 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- channels/chan_pjsip.c | 52 ++++++++++++++++++++++++++------------------------- 1 file changed, 27 insertions(+), 25 deletions(-) (limited to 'channels/chan_pjsip.c') diff --git a/channels/chan_pjsip.c b/channels/chan_pjsip.c index 015cd6448..ea55df799 100644 --- a/channels/chan_pjsip.c +++ b/channels/chan_pjsip.c @@ -701,40 +701,24 @@ static int chan_pjsip_write(struct ast_channel *ast, struct ast_frame *frame) return res; } -struct fixup_data { - struct ast_sip_session *session; - struct ast_channel *chan; -}; - -static int fixup(void *data) -{ - struct fixup_data *fix_data = data; - struct ast_sip_channel_pvt *channel = ast_channel_tech_pvt(fix_data->chan); - struct chan_pjsip_pvt *pvt = channel->pvt; - - channel->session->channel = fix_data->chan; - set_channel_on_rtp_instance(pvt, ast_channel_uniqueid(fix_data->chan)); - - return 0; -} - /*! \brief Function called by core to change the underlying owner channel */ static int chan_pjsip_fixup(struct ast_channel *oldchan, struct ast_channel *newchan) { struct ast_sip_channel_pvt *channel = ast_channel_tech_pvt(newchan); - struct fixup_data fix_data; - - fix_data.session = channel->session; - fix_data.chan = newchan; + struct chan_pjsip_pvt *pvt = channel->pvt; if (channel->session->channel != oldchan) { return -1; } - if (ast_sip_push_task_synchronous(channel->session->serializer, fixup, &fix_data)) { - ast_log(LOG_WARNING, "Unable to perform channel fixup\n"); - return -1; - } + /* + * The masquerade has suspended the channel's session + * serializer so we can safely change it outside of + * the serializer thread. + */ + channel->session->channel = newchan; + + set_channel_on_rtp_instance(pvt, ast_channel_uniqueid(newchan)); return 0; } @@ -1211,6 +1195,24 @@ static int chan_pjsip_indicate(struct ast_channel *ast, int condition, const voi case AST_CONTROL_PVT_CAUSE_CODE: res = -1; break; + case AST_CONTROL_MASQUERADE_NOTIFY: + ast_assert(datalen == sizeof(int)); + if (*(int *) data) { + /* + * Masquerade is beginning: + * Wait for session serializer to get suspended. + */ + ast_channel_unlock(ast); + ast_sip_session_suspend(channel->session); + ast_channel_lock(ast); + } else { + /* + * Masquerade is complete: + * Unsuspend the session serializer. + */ + ast_sip_session_unsuspend(channel->session); + } + break; case AST_CONTROL_HOLD: chan_pjsip_add_hold(ast_channel_uniqueid(ast)); device_buf_size = strlen(ast_channel_name(ast)) + 1; -- cgit v1.2.3