[asterisk-commits] mjordan: branch 10 r350550 - in /branches/10: apps/ bridges/ channels/ includ...
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Fri Jan 13 10:43:21 CST 2012
Author: mjordan
Date: Fri Jan 13 10:43:11 2012
New Revision: 350550
URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=350550
Log:
Fix crash from bridge channel hangup race condition in ConfBridge
This patch addresses two issues in ConfBridge and the channel bridge layer:
1. It fixes a race condition wherein the bridge channel could be hung up
2. It removes the deadlock avoidance from the bridging layer and makes the
bridge_pvt an ao2 ref counted object
Patch by David Vossel (mjordan was merely the commit monkey)
(issue ASTERISK-18988)
(closes issue ASTERISK-18885)
Reported by: Dmitry Melekhov
Tested by: Matt Jordan
Patches: chan_bridge_cleanup_v.diff uploaded by David Vossel (license 5628)
(closes issue ASTERISK-19100)
Reported by: Matt Jordan
Tested by: Matt Jordan
Review: https://reviewboard.asterisk.org/r/1654/
Modified:
branches/10/apps/app_confbridge.c
branches/10/bridges/bridge_builtin_features.c
branches/10/channels/chan_bridge.c
branches/10/include/asterisk/bridging.h
branches/10/main/bridging.c
Modified: branches/10/apps/app_confbridge.c
URL: http://svnview.digium.com/svn/asterisk/branches/10/apps/app_confbridge.c?view=diff&rev=350550&r1=350549&r2=350550
==============================================================================
--- branches/10/apps/app_confbridge.c (original)
+++ branches/10/apps/app_confbridge.c Fri Jan 13 10:43:11 2012
@@ -870,7 +870,9 @@
if (conference_bridge->playback_chan) {
struct ast_channel *underlying_channel = conference_bridge->playback_chan->tech->bridged_channel(conference_bridge->playback_chan, NULL);
- ast_hangup(underlying_channel);
+ if (underlying_channel) {
+ ast_hangup(underlying_channel);
+ }
ast_hangup(conference_bridge->playback_chan);
conference_bridge->playback_chan = NULL;
}
@@ -1151,7 +1153,7 @@
} else {
/* Channel was already available so we just need to add it back into the bridge */
underlying_channel = conference_bridge->playback_chan->tech->bridged_channel(conference_bridge->playback_chan, NULL);
- ast_bridge_impart(conference_bridge->bridge, underlying_channel, NULL, NULL);
+ ast_bridge_impart(conference_bridge->bridge, underlying_channel, NULL, NULL, 0);
}
/* The channel is all under our control, in goes the prompt */
Modified: branches/10/bridges/bridge_builtin_features.c
URL: http://svnview.digium.com/svn/asterisk/branches/10/bridges/bridge_builtin_features.c?view=diff&rev=350550&r1=350549&r2=350550
==============================================================================
--- branches/10/bridges/bridge_builtin_features.c (original)
+++ branches/10/bridges/bridge_builtin_features.c Fri Jan 13 10:43:11 2012
@@ -123,7 +123,7 @@
}
/* This is sort of the fun part. We impart the above channel onto the bridge, and have it take our place. */
- ast_bridge_impart(bridge, chan, bridge_channel->chan, NULL);
+ ast_bridge_impart(bridge, chan, bridge_channel->chan, NULL, 1);
return 0;
}
@@ -200,7 +200,7 @@
ast_bridge_features_set_flag(&called_features, AST_BRIDGE_FLAG_DISSOLVE);
/* This is how this is going down, we are imparting the channel we called above into this bridge first */
- ast_bridge_impart(attended_bridge, chan, NULL, &called_features);
+ ast_bridge_impart(attended_bridge, chan, NULL, &called_features, 1);
/* Before we join setup a features structure with the hangup option, just in case they want to use DTMF */
ast_bridge_features_init(&caller_features);
@@ -222,9 +222,9 @@
/* If the user wants to turn this into a threeway transfer then do so, otherwise they take our place */
if (attended_bridge_result == AST_BRIDGE_CHANNEL_STATE_DEPART) {
/* We want to impart them upon the bridge and just have us return to it as normal */
- ast_bridge_impart(bridge, chan, NULL, NULL);
+ ast_bridge_impart(bridge, chan, NULL, NULL, 1);
} else {
- ast_bridge_impart(bridge, chan, bridge_channel->chan, NULL);
+ ast_bridge_impart(bridge, chan, bridge_channel->chan, NULL, 1);
}
} else {
ast_stream_and_wait(bridge_channel->chan, "beeperr", AST_DIGIT_ANY);
Modified: branches/10/channels/chan_bridge.c
URL: http://svnview.digium.com/svn/asterisk/branches/10/channels/chan_bridge.c?view=diff&rev=350550&r1=350549&r2=350550
==============================================================================
--- branches/10/channels/chan_bridge.c (original)
+++ branches/10/channels/chan_bridge.c Fri Jan 13 10:43:11 2012
@@ -49,6 +49,7 @@
#include "asterisk/cli.h"
#include "asterisk/app.h"
#include "asterisk/bridging.h"
+#include "asterisk/astobj2.h"
static struct ast_channel *bridge_request(const char *type, struct ast_format_cap *cap, const struct ast_channel *requestor, void *data, int *cause);
static int bridge_call(struct ast_channel *ast, char *dest, int timeout);
@@ -71,7 +72,6 @@
};
struct bridge_pvt {
- ast_mutex_t lock; /*!< Lock that protects this structure */
struct ast_channel *input; /*!< Input channel - talking to source */
struct ast_channel *output; /*!< Output channel - talking to bridge */
};
@@ -93,27 +93,24 @@
static int bridge_write(struct ast_channel *ast, struct ast_frame *f)
{
struct bridge_pvt *p = ast->tech_pvt;
- struct ast_channel *other;
-
- ast_mutex_lock(&p->lock);
-
- other = (p->input == ast ? p->output : p->input);
-
- while (other && ast_channel_trylock(other)) {
- ast_mutex_unlock(&p->lock);
- do {
- CHANNEL_DEADLOCK_AVOIDANCE(ast);
- } while (ast_mutex_trylock(&p->lock));
- other = (p->input == ast ? p->output : p->input);
- }
-
- /* We basically queue the frame up on the other channel if present */
+ struct ast_channel *other = NULL;
+
+ ao2_lock(p);
+ /* only write frames to output. */
+ if (p->input == ast) {
+ other = p->output;
+ if (other) {
+ ast_channel_ref(other);
+ }
+ }
+ ao2_unlock(p);
+
if (other) {
+ ast_channel_unlock(ast);
ast_queue_frame(other, f);
- ast_channel_unlock(other);
- }
-
- ast_mutex_unlock(&p->lock);
+ ast_channel_lock(ast);
+ other = ast_channel_unref(other);
+ }
return 0;
}
@@ -129,31 +126,9 @@
}
/* Impart the output channel upon the given bridge of the input channel */
- ast_bridge_impart(p->input->bridge, p->output, NULL, NULL);
-
- return 0;
-}
-
-/*! \brief Helper function to not deadlock when queueing the hangup frame */
-static void bridge_queue_hangup(struct bridge_pvt *p, struct ast_channel *us)
-{
- struct ast_channel *other = (p->input == us ? p->output : p->input);
-
- while (other && ast_channel_trylock(other)) {
- ast_mutex_unlock(&p->lock);
- do {
- CHANNEL_DEADLOCK_AVOIDANCE(us);
- } while (ast_mutex_trylock(&p->lock));
- other = (p->input == us ? p->output : p->input);
- }
-
- /* We basically queue the frame up on the other channel if present */
- if (other) {
- ast_queue_hangup(other);
- ast_channel_unlock(other);
- }
-
- return;
+ ast_bridge_impart(p->input->bridge, p->output, NULL, NULL, 0);
+
+ return 0;
}
/*! \brief Called when a channel should be hung up */
@@ -161,32 +136,20 @@
{
struct bridge_pvt *p = ast->tech_pvt;
- ast_mutex_lock(&p->lock);
-
- /* Figure out which channel this is... and set it to NULL as it has gone, but also queue up a hangup frame. */
+ if (!p) {
+ return 0;
+ }
+
+ ao2_lock(p);
if (p->input == ast) {
- if (p->output) {
- bridge_queue_hangup(p, ast);
- }
p->input = NULL;
} else if (p->output == ast) {
- if (p->input) {
- bridge_queue_hangup(p, ast);
- }
p->output = NULL;
}
-
- /* Deal with the Asterisk portion of it */
+ ao2_unlock(p);
+
ast->tech_pvt = NULL;
-
- /* If both sides have been terminated free the structure and be done with things */
- if (!p->input && !p->output) {
- ast_mutex_unlock(&p->lock);
- ast_mutex_destroy(&p->lock);
- ast_free(p);
- } else {
- ast_mutex_unlock(&p->lock);
- }
+ ao2_ref(p, -1);
return 0;
}
@@ -198,26 +161,25 @@
struct ast_format slin;
/* Try to allocate memory for our very minimal pvt structure */
- if (!(p = ast_calloc(1, sizeof(*p)))) {
+ if (!(p = ao2_alloc(sizeof(*p), NULL))) {
return NULL;
}
/* Try to grab two Asterisk channels to use as input and output channels */
if (!(p->input = ast_channel_alloc(1, AST_STATE_UP, 0, 0, "", "", "", requestor ? requestor->linkedid : NULL, 0, "Bridge/%p-input", p))) {
- ast_free(p);
+ ao2_ref(p, -1);
return NULL;
}
if (!(p->output = ast_channel_alloc(1, AST_STATE_UP, 0, 0, "", "", "", requestor ? requestor->linkedid : NULL, 0, "Bridge/%p-output", p))) {
p->input = ast_channel_release(p->input);
- ast_free(p);
+ ao2_ref(p, -1);
return NULL;
}
-
- /* Setup the lock on the pvt structure, we will need that */
- ast_mutex_init(&p->lock);
/* Setup parameters on both new channels */
p->input->tech = p->output->tech = &bridge_tech;
+
+ ao2_ref(p, 2);
p->input->tech_pvt = p->output->tech_pvt = p;
ast_format_set(&slin, AST_FORMAT_SLINEAR, 0);
@@ -236,6 +198,8 @@
ast_answer(p->output);
ast_answer(p->input);
+ /* remove the reference from the alloc. The channels now own the pvt. */
+ ao2_ref(p, -1);
return p->input;
}
Modified: branches/10/include/asterisk/bridging.h
URL: http://svnview.digium.com/svn/asterisk/branches/10/include/asterisk/bridging.h?view=diff&rev=350550&r1=350549&r2=350550
==============================================================================
--- branches/10/include/asterisk/bridging.h (original)
+++ branches/10/include/asterisk/bridging.h Fri Jan 13 10:43:11 2012
@@ -156,6 +156,8 @@
int fds[4];
/*! Bit to indicate whether the channel is suspended from the bridge or not */
unsigned int suspended:1;
+ /*! Bit to indicate if a imparted channel is allowed to get hungup after leaving the bridge by the bridging core. */
+ unsigned int allow_impart_hangup:1;
/*! Features structure for features that are specific to this channel */
struct ast_bridge_features *features;
/*! Technology optimization parameters used by bridging technologies capable of
@@ -339,14 +341,15 @@
* \param chan Channel to impart
* \param swap Channel to swap out if swapping
* \param features Bridge features structure
- *
- * \retval 0 on success
- * \retval -1 on failure
- *
- * Example usage:
- *
- * \code
- * ast_bridge_impart(bridge, chan, NULL, NULL);
+ * \param allow_hangup Indicates if the bridge thread should manage hanging up of the channel or not.
+ *
+ * \retval 0 on success
+ * \retval -1 on failure
+ *
+ * Example usage:
+ *
+ * \code
+ * ast_bridge_impart(bridge, chan, NULL, NULL, 0);
* \endcode
*
* This adds a channel pointed to by the chan pointer to the bridge pointed to by
@@ -360,7 +363,7 @@
* If channel specific features are enabled a pointer to the features structure
* can be specified in the features parameter.
*/
-int ast_bridge_impart(struct ast_bridge *bridge, struct ast_channel *chan, struct ast_channel *swap, struct ast_bridge_features *features);
+int ast_bridge_impart(struct ast_bridge *bridge, struct ast_channel *chan, struct ast_channel *swap, struct ast_bridge_features *features, int allow_hangup);
/*! \brief Depart a channel from a bridge
*
Modified: branches/10/main/bridging.c
URL: http://svnview.digium.com/svn/asterisk/branches/10/main/bridging.c?view=diff&rev=350550&r1=350549&r2=350550
==============================================================================
--- branches/10/main/bridging.c (original)
+++ branches/10/main/bridging.c Fri Jan 13 10:43:11 2012
@@ -1125,7 +1125,7 @@
state = bridge_channel_join(bridge_channel);
/* If no other thread is going to take the channel then hang it up, or else we would have to service it until something else came along */
- if (state == AST_BRIDGE_CHANNEL_STATE_END || state == AST_BRIDGE_CHANNEL_STATE_HANGUP) {
+ if (bridge_channel->allow_impart_hangup && (state == AST_BRIDGE_CHANNEL_STATE_END || state == AST_BRIDGE_CHANNEL_STATE_HANGUP)) {
ast_hangup(bridge_channel->chan);
}
@@ -1141,7 +1141,7 @@
return NULL;
}
-int ast_bridge_impart(struct ast_bridge *bridge, struct ast_channel *chan, struct ast_channel *swap, struct ast_bridge_features *features)
+int ast_bridge_impart(struct ast_bridge *bridge, struct ast_channel *chan, struct ast_channel *swap, struct ast_bridge_features *features, int allow_hangup)
{
struct ast_bridge_channel *bridge_channel = bridge_channel_alloc(bridge);
/* Try to allocate a structure for the bridge channel */
@@ -1153,6 +1153,8 @@
bridge_channel->chan = chan;
bridge_channel->swap = swap;
bridge_channel->features = features;
+ bridge_channel->allow_impart_hangup = allow_hangup;
+
/* Actually create the thread that will handle the channel */
if (ast_pthread_create(&bridge_channel->thread, NULL, bridge_channel_thread, bridge_channel)) {
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