<p>Joshua Colp <strong>merged</strong> this change.</p><p><a href="https://gerrit.asterisk.org/5891">View Change</a></p><div style="white-space:pre-wrap">Approvals:
Richard Mudgett: Looks good to me, approved
Joshua Colp: Approved for Submit
</div><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, 76 insertions(+), 22 deletions(-)<br><br></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..7d66983 100644<br>--- a/include/asterisk/core_local.h<br>+++ b/include/asterisk/core_local.h<br>@@ -45,6 +45,8 @@<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> *<br>+ * \deprecated - *DO NOT USE* Please use ast_local_lock_all2 instead.<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>@@ -60,8 +62,27 @@<br> struct ast_channel **outowner);<br> <br> /*!<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 None of these locks should be held prior to calling this function.<br>+ * \note To undo this process call ast_local_unlock_all2.<br>+ *<br>+ * \since 13.17.0, 14.6.0<br>+ *<br>+ * \param chan Must be a local channel<br>+ * \param tech_pvt [out] channel's private tech (ref and 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_all2(struct ast_channel *chan, void **tech_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>+ *<br>+ * \deprecated - *DO NOT USE* Please use ast_local_unlock_all2 instead.<br> *<br> * \note This also removes references to each of the above mentioned elements and<br> * also the underlying private local structure.<br>@@ -74,6 +95,22 @@<br> void ast_local_unlock_all(struct ast_channel *chan);<br> <br> /*!<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 function should be used in conjunction with ast_local_lock_all2.<br>+ *<br>+ * \since 13.17.0, 14.6.0<br>+ *<br>+ * \param tech_pvt channel's private tech (ref and 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_all2(void *tech_pvt, struct ast_channel *base_chan,<br>+ struct ast_channel *base_owner);<br>+<br>+/*!<br> * \brief Get the other local channel in the pair.<br> * \since 12.0.0<br> *<br>diff --git a/main/bridge.c b/main/bridge.c<br>index 6152b1b..38c56cc 100644<br>--- a/main/bridge.c<br>+++ b/main/bridge.c<br>@@ -4240,14 +4240,15 @@<br> BRIDGE_LOCK_ONE_OR_BOTH(bridge1, bridge2);<br> <br> if (bridge2) {<br>+ void *tech;<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_all2(local_chan, &tech, &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_all2(tech, locals[0], locals[1]);<br> ao2_cleanup(local_chan);<br> return AST_BRIDGE_TRANSFER_FAIL;<br> }<br>@@ -4258,7 +4259,7 @@<br> }<br> <br> ast_attended_transfer_message_add_link(transfer_msg, locals);<br>- ast_local_unlock_all(local_chan);<br>+ ast_local_unlock_all2(tech, 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 1b8ebf6..a5918f5 100644<br>--- a/main/core_local.c<br>+++ b/main/core_local.c<br>@@ -235,17 +235,45 @@<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_all2(struct ast_channel *chan, void **tech_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_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>+ ast_unreal_lock_all(&p->base, base_chan, base_owner);<br>+ }<br>+}<br>+<br>+void ast_local_lock_all(struct ast_channel *chan, struct ast_channel **outchan,<br>+ struct ast_channel **outowner)<br>+{<br>+ void *tech_pvt;<br>+ ast_local_lock_all2(chan, &tech_pvt, outchan, outowner);<br>+}<br>+<br>+void ast_local_unlock_all2(void *tech_pvt, struct ast_channel *base_chan,<br>+ struct ast_channel *base_owner)<br>+{<br>+ if (base_chan) {<br>+ ast_channel_unlock(base_chan);<br>+ ast_channel_unref(base_chan);<br>+ }<br>+<br>+ if (base_owner) {<br>+ ast_channel_unlock(base_owner);<br>+ ast_channel_unref(base_owner);<br>+ }<br>+<br>+ if (tech_pvt) {<br>+ struct local_pvt *p = tech_pvt;<br>+ ao2_unlock(&p->base);<br>+ ao2_ref(tech_pvt, -1);<br> }<br> }<br> <br>@@ -259,19 +287,7 @@<br> }<br> <br> base = &p->base;<br>-<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>- }<br>-<br>- ao2_unlock(base);<br>- ao2_ref(p, -1);<br>+ ast_local_unlock_all2(p, base->chan, base->owner);<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/5891">change 5891</a>. 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<div style="display:none"> Gerrit-Project: asterisk </div>
<div style="display:none"> Gerrit-Branch: certified/13.13 </div>
<div style="display:none"> Gerrit-MessageType: merged </div>
<div style="display:none"> Gerrit-Change-Id: Ice96653e29bd9d6674ed5f95feb6b448ab148b09 </div>
<div style="display:none"> Gerrit-Change-Number: 5891 </div>
<div style="display:none"> Gerrit-PatchSet: 4 </div>
<div style="display:none"> Gerrit-Owner: Kevin Harwell <kharwell@digium.com> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins2 </div>
<div style="display:none"> Gerrit-Reviewer: Joshua Colp <jcolp@digium.com> </div>
<div style="display:none"> Gerrit-Reviewer: Richard Mudgett <rmudgett@digium.com> </div>