[svn-commits] rmudgett: branch 1.8 r334009 - in /branches/1.8: channels/ main/
SVN commits to the Digium repositories
svn-commits at lists.digium.com
Wed Aug 31 10:20:37 CDT 2011
Author: rmudgett
Date: Wed Aug 31 10:20:31 2011
New Revision: 334009
URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=334009
Log:
Call pickup race leaves orphaned channels or crashes.
Multiple users attempting to pickup a call that has been forked to
multiple extensions either crashes or fails a masquerade with a "bad
things may happen" message.
This is the scenario that is causing all the grief:
1) Pickup target is selected
2) target is marked as being picked up in ast_do_pickup()
3) target is unlocked by ast_do_pickup()
4) app dial or queue gets a chance to hang up losing calls and calls
ast_hangup() on target
5) SINCE A MASQUERADE HAS NOT BEEN SETUP YET BY ast_do_pickup() with
ast_channel_masquerade(), ast_hangup() completes successfully and the
channel is no longer in the channels container.
6) ast_do_pickup() then calls ast_channel_masquerade() to schedule the
masquerade on the dead channel.
7) ast_do_pickup() then calls ast_do_masquerade() on the dead channel
8) bad things happen while doing the masquerade and in the process
ast_do_masquerade() puts the dead channel back into the channels container
9) The "orphaned" channel is visible in the channels list if a crash does
not happen.
This patch does the following:
* Made ast_hangup() set AST_FLAG_ZOMBIE on a successfully hung-up channel
and not release the channel lock until that has happened.
* Made __ast_channel_masquerade() not setup a masquerade if either channel
has AST_FLAG_ZOMBIE set.
* Fix chan_agent misuse of AST_FLAG_ZOMBIE since it would no longer work.
(closes issue ASTERISK-18222)
Reported by: Alec Davis
Tested by: rmudgett, Alec Davis, irroot, Karsten Wemheuer
(closes issue ASTERISK-18273)
Reported by: Karsten Wemheuer
Tested by: rmudgett, Alec Davis, irroot, Karsten Wemheuer
Review: https://reviewboard.asterisk.org/r/1400/
Modified:
branches/1.8/channels/chan_agent.c
branches/1.8/main/channel.c
Modified: branches/1.8/channels/chan_agent.c
URL: http://svnview.digium.com/svn/asterisk/branches/1.8/channels/chan_agent.c?view=diff&rev=334009&r1=334008&r2=334009
==============================================================================
--- branches/1.8/channels/chan_agent.c (original)
+++ branches/1.8/channels/chan_agent.c Wed Aug 31 10:20:31 2011
@@ -1300,10 +1300,8 @@
ast_setstate(parent, AST_STATE_UP);
ast_setstate(chan, AST_STATE_UP);
ast_copy_string(parent->context, chan->context, sizeof(parent->context));
- /* Go ahead and mark the channel as a zombie so that masquerade will
- destroy it for us, and we need not call ast_hangup */
- ast_set_flag(chan, AST_FLAG_ZOMBIE);
ast_channel_masquerade(parent, chan);
+ ast_hangup(chan);
p->abouttograb = 0;
} else {
ast_debug(1, "Sneaky, parent disappeared in the mean time...\n");
Modified: branches/1.8/main/channel.c
URL: http://svnview.digium.com/svn/asterisk/branches/1.8/main/channel.c?view=diff&rev=334009&r1=334008&r2=334009
==============================================================================
--- branches/1.8/main/channel.c (original)
+++ branches/1.8/main/channel.c Wed Aug 31 10:20:31 2011
@@ -2731,47 +2731,57 @@
/*! \brief Hangup a channel */
int ast_hangup(struct ast_channel *chan)
{
- int res = 0;
char extra_str[64]; /* used for cel logging below */
- /* Don't actually hang up a channel that will masquerade as someone else, or
- if someone is going to masquerade as us */
+ ast_autoservice_stop(chan);
+
+ ao2_lock(channels);
ast_channel_lock(chan);
if (chan->audiohooks) {
ast_audiohook_detach_list(chan->audiohooks);
chan->audiohooks = NULL;
}
-
ast_framehook_list_destroy(chan);
- ast_autoservice_stop(chan);
-
- if (chan->masq) {
+ /*
+ * Do the masquerade if someone is setup to masquerade into us.
+ *
+ * NOTE: We must hold the channel lock after testing for a
+ * pending masquerade and setting the channel as a zombie to
+ * prevent __ast_channel_masquerade() from setting up a
+ * masquerade with a dead channel.
+ */
+ while (chan->masq) {
ast_channel_unlock(chan);
+ ao2_unlock(channels);
if (ast_do_masquerade(chan)) {
ast_log(LOG_WARNING, "Failed to perform masquerade\n");
- }
+
+ /* Abort the loop or we might never leave. */
+ ao2_lock(channels);
+ ast_channel_lock(chan);
+ break;
+ }
+ ao2_lock(channels);
ast_channel_lock(chan);
}
- if (chan->masq) {
- ast_log(LOG_WARNING, "%s getting hung up, but someone is trying to masq into us?!?\n", chan->name);
- ast_channel_unlock(chan);
- return 0;
- }
- /* If this channel is one which will be masqueraded into something,
- mark it as a zombie already, so we know to free it later */
if (chan->masqr) {
+ /*
+ * This channel is one which will be masqueraded into something.
+ * Mark it as a zombie already so ast_do_masquerade() will know
+ * to free it later.
+ */
ast_set_flag(chan, AST_FLAG_ZOMBIE);
ast_channel_unlock(chan);
+ ao2_unlock(channels);
return 0;
}
- ast_channel_unlock(chan);
ao2_unlink(channels, chan);
-
- ast_channel_lock(chan);
+ ao2_unlock(channels);
+
free_translation(chan);
/* Close audio stream */
if (chan->stream) {
@@ -2788,9 +2798,11 @@
chan->sched = NULL;
}
- if (chan->generatordata) /* Clear any tone stuff remaining */
- if (chan->generator && chan->generator->release)
+ if (chan->generatordata) { /* Clear any tone stuff remaining */
+ if (chan->generator && chan->generator->release) {
chan->generator->release(chan, chan->generatordata);
+ }
+ }
chan->generatordata = NULL;
chan->generator = NULL;
@@ -2799,19 +2811,27 @@
if (ast_test_flag(chan, AST_FLAG_BLOCKING)) {
ast_log(LOG_WARNING, "Hard hangup called by thread %ld on %s, while fd "
- "is blocked by thread %ld in procedure %s! Expect a failure\n",
- (long)pthread_self(), chan->name, (long)chan->blocker, chan->blockproc);
+ "is blocked by thread %ld in procedure %s! Expect a failure\n",
+ (long) pthread_self(), chan->name, (long)chan->blocker, chan->blockproc);
ast_assert(ast_test_flag(chan, AST_FLAG_BLOCKING) == 0);
}
if (!ast_test_flag(chan, AST_FLAG_ZOMBIE)) {
ast_debug(1, "Hanging up channel '%s'\n", chan->name);
- if (chan->tech->hangup)
- res = chan->tech->hangup(chan);
+
+ /*
+ * This channel is now dead so mark it as a zombie so anyone
+ * left holding a reference to this channel will not use it.
+ */
+ ast_set_flag(chan, AST_FLAG_ZOMBIE);
+ if (chan->tech->hangup) {
+ chan->tech->hangup(chan);
+ }
} else {
ast_debug(1, "Hanging up zombie '%s'\n", chan->name);
}
-
+
ast_channel_unlock(chan);
+
ast_cc_offer(chan);
ast_manager_event(chan, EVENT_FLAG_CALL, "Hangup",
"Channel: %s\r\n"
@@ -2832,20 +2852,19 @@
ast_cause2str(chan->hangupcause)
);
- if (chan->cdr && !ast_test_flag(chan->cdr, AST_CDR_FLAG_BRIDGED) &&
- !ast_test_flag(chan->cdr, AST_CDR_FLAG_POST_DISABLED) &&
- (chan->cdr->disposition != AST_CDR_NULL || ast_test_flag(chan->cdr, AST_CDR_FLAG_DIALED))) {
+ if (chan->cdr && !ast_test_flag(chan->cdr, AST_CDR_FLAG_BRIDGED) &&
+ !ast_test_flag(chan->cdr, AST_CDR_FLAG_POST_DISABLED) &&
+ (chan->cdr->disposition != AST_CDR_NULL || ast_test_flag(chan->cdr, AST_CDR_FLAG_DIALED))) {
ast_channel_lock(chan);
-
ast_cdr_end(chan->cdr);
ast_cdr_detach(chan->cdr);
chan->cdr = NULL;
ast_channel_unlock(chan);
}
- chan = ast_channel_release(chan);
-
- return res;
+ ast_channel_unref(chan);
+
+ return 0;
}
int ast_raw_answer(struct ast_channel *chan, int cdr_answer)
@@ -5738,48 +5757,81 @@
int res = -1;
struct ast_channel *final_orig, *final_clone, *base;
-retrymasq:
- final_orig = original;
- final_clone = clonechan;
-
- ast_channel_lock(original);
- while (ast_channel_trylock(clonechan)) {
- ast_channel_unlock(original);
- usleep(1);
- ast_channel_lock(original);
- }
-
- /* each of these channels may be sitting behind a channel proxy (i.e. chan_agent)
- and if so, we don't really want to masquerade it, but its proxy */
- if (original->_bridge && (original->_bridge != ast_bridged_channel(original)) && (original->_bridge->_bridge != original))
- final_orig = original->_bridge;
-
- if (clonechan->_bridge && (clonechan->_bridge != ast_bridged_channel(clonechan)) && (clonechan->_bridge->_bridge != clonechan))
- final_clone = clonechan->_bridge;
-
- if (final_clone->tech->get_base_channel && (base = final_clone->tech->get_base_channel(final_clone))) {
- final_clone = base;
- }
-
- if ((final_orig != original) || (final_clone != clonechan)) {
- /* Lots and lots of deadlock avoidance. The main one we're competing with
- * is ast_write(), which locks channels recursively, when working with a
- * proxy channel. */
- if (ast_channel_trylock(final_orig)) {
+ for (;;) {
+ final_orig = original;
+ final_clone = clonechan;
+
+ ast_channel_lock_both(original, clonechan);
+
+ if (ast_test_flag(original, AST_FLAG_ZOMBIE)
+ || ast_test_flag(clonechan, AST_FLAG_ZOMBIE)) {
+ /* Zombies! Run! */
+ ast_log(LOG_WARNING,
+ "Can't setup masquerade. One or both channels is dead. (%s <-- %s)\n",
+ original->name, clonechan->name);
ast_channel_unlock(clonechan);
ast_channel_unlock(original);
- goto retrymasq;
- }
- if (ast_channel_trylock(final_clone)) {
- ast_channel_unlock(final_orig);
+ return -1;
+ }
+
+ /*
+ * Each of these channels may be sitting behind a channel proxy
+ * (i.e. chan_agent) and if so, we don't really want to
+ * masquerade it, but its proxy
+ */
+ if (original->_bridge
+ && (original->_bridge != ast_bridged_channel(original))
+ && (original->_bridge->_bridge != original)) {
+ final_orig = original->_bridge;
+ }
+ if (clonechan->_bridge
+ && (clonechan->_bridge != ast_bridged_channel(clonechan))
+ && (clonechan->_bridge->_bridge != clonechan)) {
+ final_clone = clonechan->_bridge;
+ }
+ if (final_clone->tech->get_base_channel
+ && (base = final_clone->tech->get_base_channel(final_clone))) {
+ final_clone = base;
+ }
+
+ if ((final_orig != original) || (final_clone != clonechan)) {
+ /*
+ * Lots and lots of deadlock avoidance. The main one we're
+ * competing with is ast_write(), which locks channels
+ * recursively, when working with a proxy channel.
+ */
+ if (ast_channel_trylock(final_orig)) {
+ ast_channel_unlock(clonechan);
+ ast_channel_unlock(original);
+
+ /* Try again */
+ continue;
+ }
+ if (ast_channel_trylock(final_clone)) {
+ ast_channel_unlock(final_orig);
+ ast_channel_unlock(clonechan);
+ ast_channel_unlock(original);
+
+ /* Try again */
+ continue;
+ }
ast_channel_unlock(clonechan);
ast_channel_unlock(original);
- goto retrymasq;
- }
- ast_channel_unlock(clonechan);
- ast_channel_unlock(original);
- original = final_orig;
- clonechan = final_clone;
+ original = final_orig;
+ clonechan = final_clone;
+
+ if (ast_test_flag(original, AST_FLAG_ZOMBIE)
+ || ast_test_flag(clonechan, AST_FLAG_ZOMBIE)) {
+ /* Zombies! Run! */
+ ast_log(LOG_WARNING,
+ "Can't setup masquerade. One or both channels is dead. (%s <-- %s)\n",
+ original->name, clonechan->name);
+ ast_channel_unlock(clonechan);
+ ast_channel_unlock(original);
+ return -1;
+ }
+ }
+ break;
}
if (original == clonechan) {
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