<p>Kevin Harwell has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.asterisk.org/5890">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">core_local: local channel data not being properly unref'ed and unlocked<br><br>In an earlier version of Asterisk a local channel [un]lock all functions were<br>added in order to keep a crash from occurring when a channel hung up too early<br>during an attended transfer. Unfortunately, when a transfer failure occurs and<br>depending on the timing, the local channels sometime do not get properly<br>unlocked and deref'ed after being locked and ref'ed. This happens because the<br>underlying local channel structure gets NULLed out before unlocking.<br><br>This patch reworks those [un]lock functions and makes sure the values that get<br>locked and ref'ed later get unlocked and deref'ed.<br><br>ASTERISK-27074 #close<br><br>Change-Id: Ice96653e29bd9d6674ed5f95feb6b448ab148b09<br>---<br>M include/asterisk/core_local.h<br>M main/bridge.c<br>M main/core_local.c<br>3 files changed, 57 insertions(+), 42 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/90/5890/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">diff --git a/include/asterisk/core_local.h b/include/asterisk/core_local.h<br>index 8557072..b9e4065 100644<br>--- a/include/asterisk/core_local.h<br>+++ b/include/asterisk/core_local.h<br>@@ -42,36 +42,40 @@<br> /* ------------------------------------------------------------------- */<br> <br> /*!<br>- * \brief Lock the "chan" and "owner" channels (and return them) on the base<br>- * private structure as well as the base private structure itself.<br>+ * \brief Add a reference to the local channel's private tech, lock the local channel's<br>+ * private base, and add references and lock both sides of the local channel.<br> *<br>- * \note This also adds references to each of the above mentioned elements and<br>- * also the underlying private local structure.<br> * \note None of these locks should be held prior to calling this function.<br>- * \note To undo this process call ast_local_unlock_all.<br>+ * \note To undo this process call ast_local_unlock_all2.<br> *<br>- * \since 13.8.0<br>+ * \since 13.17.0, 14.6.0<br> *<br> * \param chan Must be a local channel<br>- * \param outchan The local channel's "chan" channel<br>- * \param outowner The local channel's "owner" channel<br>+ * \param tech_pvt [out] channel's private tech (ref added)<br>+ * \param base_pvt [out] channel's private base (lock added)<br>+ * \param base_chan [out] One side of the local channel (ref and lock added)<br>+ * \param base_owner [out] Other side of the local channel (ref and lock added)<br> */<br>-void ast_local_lock_all(struct ast_channel *chan, struct ast_channel **outchan,<br>- struct ast_channel **outowner);<br>+void ast_local_lock_all(struct ast_channel *chan, void **tech_pvt, void **base_pvt,<br>+ struct ast_channel **base_chan, struct ast_channel **base_owner);<br> <br> /*!<br>- * \brief Unlock the "chan" and "owner" channels on the base private structure<br>- * as well as the base private structure itself.<br>+ * \brief Remove a reference to the given local channel's private tech, unlock the given<br>+ * local channel's private base, and remove references and unlock both sides of<br>+ * given the local channel.<br> *<br>- * \note This also removes references to each of the above mentioned elements and<br>- * also the underlying private local structure.<br>- * \note This function should be used in conjunction with ast_local_lock_all.<br>+ * \note This function should be used in conjunction with ast_local_lock_all2.<br> *<br>- * \since 13.8.0<br>+ * \since 13.17.0, 14.6.0<br> *<br> * \param chan Must be a local channel<br>+ * \param tech_pvt channel's private tech (ref removed)<br>+ * \param base_pvt channel's private base (lock removed)<br>+ * \param base_chan One side of the local channel (ref and lock removed)<br>+ * \param base_owner Other side of the local channel (ref and lock removed)<br> */<br>-void ast_local_unlock_all(struct ast_channel *chan);<br>+void ast_local_unlock_all(struct ast_channel *chan, void *tech_pvt, void *base_pvt,<br>+ struct ast_channel *base_chan, struct ast_channel *base_owner);<br> <br> /*!<br> * \brief Get the other local channel in the pair.<br>diff --git a/main/bridge.c b/main/bridge.c<br>index 8cde62c..34176c7 100644<br>--- a/main/bridge.c<br>+++ b/main/bridge.c<br>@@ -4276,14 +4276,15 @@<br> BRIDGE_LOCK_ONE_OR_BOTH(bridge1, bridge2);<br> <br> if (bridge2) {<br>+ void *tech, *base;<br> struct ast_channel *locals[2];<br> <br> /* Have to lock everything just in case a hangup comes in early */<br>- ast_local_lock_all(local_chan, &locals[0], &locals[1]);<br>+ ast_local_lock_all(local_chan, &tech, &base, &locals[0], &locals[1]);<br> if (!locals[0] || !locals[1]) {<br> ast_log(LOG_ERROR, "Transfer failed probably due to an early hangup - "<br> "missing other half of '%s'\n", ast_channel_name(local_chan));<br>- ast_local_unlock_all(local_chan);<br>+ ast_local_unlock_all(local_chan, tech, base, locals[0], locals[1]);<br> ao2_cleanup(local_chan);<br> return AST_BRIDGE_TRANSFER_FAIL;<br> }<br>@@ -4294,7 +4295,7 @@<br> }<br> <br> ast_attended_transfer_message_add_link(transfer_msg, locals);<br>- ast_local_unlock_all(local_chan);<br>+ ast_local_unlock_all(local_chan, tech, base, locals[0], locals[1]);<br> } else {<br> ast_attended_transfer_message_add_app(transfer_msg, app, local_chan);<br> }<br>diff --git a/main/core_local.c b/main/core_local.c<br>index aa232a4..dcebb20 100644<br>--- a/main/core_local.c<br>+++ b/main/core_local.c<br>@@ -233,43 +233,53 @@<br> char exten[AST_MAX_EXTENSION];<br> };<br> <br>-void ast_local_lock_all(struct ast_channel *chan, struct ast_channel **outchan,<br>- struct ast_channel **outowner)<br>+void ast_local_lock_all(struct ast_channel *chan, void **tech_pvt, void **base_pvt,<br>+ struct ast_channel **base_chan, struct ast_channel **base_owner)<br> {<br> struct local_pvt *p = ast_channel_tech_pvt(chan);<br> <br>- *outchan = NULL;<br>- *outowner = NULL;<br>+ *tech_pvt = NULL;<br>+ *base_pvt = NULL;<br>+ *base_chan = NULL;<br>+ *base_owner = NULL;<br> <br> if (p) {<br>- ao2_ref(p, 1);<br>- ast_unreal_lock_all(&p->base, outchan, outowner);<br>+ *tech_pvt = ao2_bump(p);<br>+ *base_pvt = &p->base;<br>+ ast_unreal_lock_all(*base_pvt, base_chan, base_owner);<br> }<br>+<br>+ ast_debug(5, "Local lock all - tech private = %p, base private = %p, base chan = %p,"<br>+ " base owner = %p\n", *tech_pvt, *base_pvt, *base_chan, *base_owner);<br> }<br> <br>-void ast_local_unlock_all(struct ast_channel *chan)<br>+void ast_local_unlock_all(struct ast_channel *chan, void *tech_pvt, void *base_pvt,<br>+ struct ast_channel *base_chan, struct ast_channel *base_owner)<br> {<br>- struct local_pvt *p = ast_channel_tech_pvt(chan);<br>- struct ast_unreal_pvt *base;<br>+ struct local_pvt *local = ast_channel_tech_pvt(chan);<br>+ struct ast_unreal_pvt *unreal = local ? &local->base : NULL;<br>+ struct ast_channel *unreal_chan = unreal ? unreal->chan : NULL;<br>+ struct ast_channel *unreal_owner = unreal ? unreal->owner : NULL;<br> <br>- if (!p) {<br>- return;<br>+<br>+ ast_debug(5, "Local unlock all - local private = %p|%p, unreal private = %p|%p, "<br>+ "base chan = %p|%p, base owner = %p|%p\n", local, tech_pvt, unreal,<br>+ base_pvt, unreal_chan, base_chan, unreal_owner, base_owner);<br>+<br>+ if (base_chan) {<br>+ ast_channel_unlock(base_chan);<br>+ ast_channel_unref(base_chan);<br> }<br> <br>- base = &p->base;<br>-<br>- if (base->owner) {<br>- ast_channel_unlock(base->owner);<br>- ast_channel_unref(base->owner);<br>+ if (base_owner) {<br>+ ast_channel_unlock(base_owner);<br>+ ast_channel_unref(base_owner);<br> }<br> <br>- if (base->chan) {<br>- ast_channel_unlock(base->chan);<br>- ast_channel_unref(base->chan);<br>+ if (base_pvt) {<br>+ ao2_unlock(base_pvt);<br> }<br>-<br>- ao2_unlock(base);<br>- ao2_ref(p, -1);<br>+ ao2_cleanup(tech_pvt);<br> }<br> <br> struct ast_channel *ast_local_get_peer(struct ast_channel *ast)<br></pre><p>To view, visit <a href="https://gerrit.asterisk.org/5890">change 5890</a>. 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<div style="display:none"> Gerrit-Project: asterisk </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>
<div style="display:none"> Gerrit-Change-Id: Ice96653e29bd9d6674ed5f95feb6b448ab148b09 </div>
<div style="display:none"> Gerrit-Change-Number: 5890 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: Kevin Harwell <kharwell@digium.com> </div>