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bridge_native_rtp: Deadlock during 4-way conference creation

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The change contains a slightly adjusted patch that was on the issue
(submitted by kmoore).  A fix was made by adding in a bridge lock
while calling bridge_start/stop from the framehook callback.  Since
the framehook callback is not called from the bridging core the bridge
is not locked, but needs to be before calling bridge_start.

(closes issue ASTERISK-22749)
Reported by: Kinsey Moore
Review: https://reviewboard.asterisk.org/r/3066/
Patches:
     lock_inversion.diff uploaded by kmoore (license 6273)
........

Merged revisions 403767 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@403768 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Kevin Harwell
2013-12-13 18:33:25 +00:00
parent f425c4a086
commit 84e1790beb
5 changed files with 39 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
bridges/bridge_native_rtp.c
View File

@@ -112,7 +112,16 @@ static enum ast_rtp_glue_result native_rtp_bridge_get(struct ast_channel *c0, st
return audio_glue0_res;
}
static int native_rtp_bridge_start(struct ast_bridge *bridge, struct ast_channel *target)
/*!
* \internal
* \brief Start native RTP bridging of two channels
*
* \param bridge The bridge that had native RTP bridging happening on it
* \param target If remote RTP bridging, the channel that is unheld.
*
* \note Bridge must be locked when calling this function.
*/
static void native_rtp_bridge_start(struct ast_bridge *bridge, struct ast_channel *target)
{
struct ast_bridge_channel *c0 = AST_LIST_FIRST(&bridge->channels);
struct ast_bridge_channel *c1 = AST_LIST_LAST(&bridge->channels);
@@ -128,18 +137,12 @@ static int native_rtp_bridge_start(struct ast_bridge *bridge, struct ast_channel
RAII_VAR(struct ast_format_cap *, cap1, ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_NOLOCK), ast_format_cap_destroy);
if (c0 == c1) {
return 0;
return;
}
ast_channel_lock_both(c0->chan, c1->chan);
native_type = native_rtp_bridge_get(c0->chan, c1->chan, &glue0, &glue1, &instance0, &instance1, &vinstance0, &vinstance1);
if (glue0->get_codec) {
glue0->get_codec(c0->chan, cap0);
}
if (glue1->get_codec) {
glue1->get_codec(c1->chan, cap1);
}
switch (native_type) {
case AST_RTP_GLUE_RESULT_LOCAL:
if (ast_rtp_instance_get_engine(instance0)->local_bridge) {
@@ -155,6 +158,12 @@ static int native_rtp_bridge_start(struct ast_bridge *bridge, struct ast_channel
break;
case AST_RTP_GLUE_RESULT_REMOTE:
if (glue0->get_codec) {
glue0->get_codec(c0->chan, cap0);
}
if (glue1->get_codec) {
glue1->get_codec(c1->chan, cap1);
}
/* If we have a target, it's the channel that received the UNHOLD or UPDATE_RTP_PEER frame and was told to resume */
if (!target) {
@@ -180,7 +189,8 @@ static int native_rtp_bridge_start(struct ast_bridge *bridge, struct ast_channel
break;
}
return 0;
ast_channel_unlock(c0->chan);
ast_channel_unlock(c1->chan);
}
static void native_rtp_bridge_stop(struct ast_bridge *bridge, struct ast_channel *target)
@@ -202,6 +212,7 @@ static void native_rtp_bridge_stop(struct ast_bridge *bridge, struct ast_channel
return;
}
ast_channel_lock_both(c0->chan, c1->chan);
native_type = native_rtp_bridge_get(c0->chan, c1->chan, &glue0, &glue1, &instance0, &instance1, &vinstance0, &vinstance1);
switch (native_type) {
@@ -241,6 +252,9 @@ static void native_rtp_bridge_stop(struct ast_bridge *bridge, struct ast_channel
ast_debug(2, "Discontinued RTP bridging of '%s' and '%s' - media will flow through Asterisk core\n",
ast_channel_name(c0->chan), ast_channel_name(c1->chan));
ast_channel_unlock(c0->chan);
ast_channel_unlock(c1->chan);
}
/*! \brief Frame hook that is called to intercept hold/unhold */
@@ -252,16 +266,23 @@ static struct ast_frame *native_rtp_framehook(struct ast_channel *chan, struct a
return f;
}
ast_channel_lock(chan);
bridge = ast_channel_get_bridge(chan);
ast_channel_unlock(chan);
if (bridge) {
/* native_rtp_bridge_start/stop are not being called from bridging
core so we need to lock the bridge prior to calling these functions
Unfortunately that means unlocking the channel, but as it
should not be modified this should be okay...hopefully */
ast_channel_unlock(chan);
ast_bridge_lock(bridge);
if (f->subclass.integer == AST_CONTROL_HOLD) {
native_rtp_bridge_stop(bridge, chan);
} else if ((f->subclass.integer == AST_CONTROL_UNHOLD) || (f->subclass.integer == AST_CONTROL_UPDATE_RTP_PEER)) {
native_rtp_bridge_start(bridge, chan);
}
ast_bridge_unlock(bridge);
ast_channel_lock(chan);
}
return f;
@@ -412,7 +433,8 @@ static int native_rtp_bridge_join(struct ast_bridge *bridge, struct ast_bridge_c
return -1;
}
return native_rtp_bridge_start(bridge, NULL);
native_rtp_bridge_start(bridge, NULL);
return 0;
}
static void native_rtp_bridge_unsuspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)