gentoo resync : 31.05.2021

2 files changed, 598 insertions, 0 deletions

diff --git a/net-misc/asterisk/files/asterisk-13.38.2-r3-func_lock-fix-races.patch b/net-misc/asterisk/files/asterisk-13.38.2-r3-func_lock-fix-races.patch
new file mode 100644
index 000000000000..3d3c7b101d47
--- /dev/null
+++ b/net-misc/asterisk/files/asterisk-13.38.2-r3-func_lock-fix-races.patch
@@ -0,0 +1,421 @@
+From b35211fd58afcf430a0d95a243dc7a086d72b2b8 Mon Sep 17 00:00:00 2001
+From: Jaco Kroon <jaco@uls.co.za>
+Date: Fri, 21 May 2021 20:11:59 +0200
+Subject: [PATCH] Replacement patch for v13.
+
+Change-Id: I30236d7d7229f317c681fb7c6d7944d6108acd08
+---
+ funcs/func_lock.c | 234 +++++++++++++++++++++++++---------------------
+ 1 file changed, 126 insertions(+), 108 deletions(-)
+
+diff --git a/funcs/func_lock.c b/funcs/func_lock.c
+index a006a574eb..c472504f52 100644
+--- a/funcs/func_lock.c
++++ b/funcs/func_lock.c
+@@ -44,6 +44,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+ #include "asterisk/linkedlists.h"
+ #include "asterisk/astobj2.h"
+ #include "asterisk/utils.h"
++#include "asterisk/cli.h"
+ 
+ /*** DOCUMENTATION
+ 	<function name="LOCK" language="en_US">
+@@ -112,7 +113,6 @@ static AST_LIST_HEAD_STATIC(locklist, lock_frame);
+ static void lock_free(void *data);
+ static void lock_fixup(void *data, struct ast_channel *oldchan, struct ast_channel *newchan);
+ static int unloading = 0;
+-static pthread_t broker_tid = AST_PTHREADT_NULL;
+ 
+ static const struct ast_datastore_info lock_info = {
+ 	.type = "MUTEX",
+@@ -126,8 +126,8 @@ struct lock_frame {
+ 	ast_cond_t cond;
+ 	/*! count is needed so if a recursive mutex exits early, we know how many times to unlock it. */
+ 	unsigned int count;
+-	/*! Container of requesters for the named lock */
+-	struct ao2_container *requesters;
++	/*! Count of waiting of requesters for the named lock */
++	unsigned int requesters;
+ 	/*! who owns us */
+ 	struct ast_channel *owner;
+ 	/*! name of the lock */
+@@ -149,14 +149,19 @@ static void lock_free(void *data)
+ 	while ((clframe = AST_LIST_REMOVE_HEAD(oldlist, list))) {
+ 		/* Only unlock if we own the lock */
+ 		if (clframe->channel == clframe->lock_frame->owner) {
++			ast_mutex_lock(&clframe->lock_frame->mutex);
+ 			clframe->lock_frame->count = 0;
+ 			clframe->lock_frame->owner = NULL;
++			ast_cond_signal(&clframe->lock_frame->cond);
++			ast_mutex_unlock(&clframe->lock_frame->mutex);
+ 		}
+ 		ast_free(clframe);
+ 	}
+ 	AST_LIST_UNLOCK(oldlist);
+ 	AST_LIST_HEAD_DESTROY(oldlist);
+ 	ast_free(oldlist);
++
++	ast_module_unref(ast_module_info->self);
+ }
+ 
+ static void lock_fixup(void *data, struct ast_channel *oldchan, struct ast_channel *newchan)
+@@ -175,54 +180,11 @@ static void lock_fixup(void *data, struct ast_channel *oldchan, struct ast_chann
+ 		if (clframe->lock_frame->owner == oldchan) {
+ 			clframe->lock_frame->owner = newchan;
+ 		}
+-		/* We don't move requesters, because the thread stack is different */
+ 		clframe->channel = newchan;
+ 	}
+ 	AST_LIST_UNLOCK(list);
+ }
+ 
+-static void *lock_broker(void *unused)
+-{
+-	struct lock_frame *frame;
+-	struct timespec forever = { 1000000, 0 };
+-	for (;;) {
+-		int found_requester = 0;
+-
+-		/* Test for cancel outside of the lock */
+-		pthread_testcancel();
+-		AST_LIST_LOCK(&locklist);
+-
+-		AST_LIST_TRAVERSE(&locklist, frame, entries) {
+-			if (ao2_container_count(frame->requesters)) {
+-				found_requester++;
+-				ast_mutex_lock(&frame->mutex);
+-				if (!frame->owner) {
+-					ast_cond_signal(&frame->cond);
+-				}
+-				ast_mutex_unlock(&frame->mutex);
+-			}
+-		}
+-
+-		AST_LIST_UNLOCK(&locklist);
+-		pthread_testcancel();
+-
+-		/* If there are no requesters, then wait for a signal */
+-		if (!found_requester) {
+-			nanosleep(&forever, NULL);
+-		} else {
+-			sched_yield();
+-		}
+-	}
+-	/* Not reached */
+-	return NULL;
+-}
+-
+-static int ast_channel_cmp_cb(void *obj, void *arg, int flags)
+-{
+-	struct ast_channel *chan = obj, *cmp_args = arg;
+-	return strcasecmp(ast_channel_name(chan), ast_channel_name(cmp_args)) ? 0 : CMP_MATCH;
+-}
+-
+ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ {
+ 	struct ast_datastore *lock_store = ast_channel_datastore_find(chan, &lock_info, NULL);
+@@ -234,7 +196,12 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 	struct timeval now;
+ 
+ 	if (!lock_store) {
+-		ast_debug(1, "Channel %s has no lock datastore, so we're allocating one.\n", ast_channel_name(chan));
++		if (unloading) {
++			ast_log(LOG_ERROR, "%sLOCK has no datastore and func_lock is unloading, failing.\n",
++					trylock ? "TRY" : "");
++			return -1;
++		}
++
+ 		lock_store = ast_datastore_alloc(&lock_info, NULL);
+ 		if (!lock_store) {
+ 			ast_log(LOG_ERROR, "Unable to allocate new datastore.  No locks will be obtained.\n");
+@@ -253,6 +220,9 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 		lock_store->data = list;
+ 		AST_LIST_HEAD_INIT(list);
+ 		ast_channel_datastore_add(chan, lock_store);
++
++		/* We cannot unload until this channel has released the lock_store */
++		ast_module_ref(ast_module_info->self);
+ 	} else
+ 		list = lock_store->data;
+ 
+@@ -266,6 +236,9 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 
+ 	if (!current) {
+ 		if (unloading) {
++			ast_log(LOG_ERROR,
++				"Lock doesn't exist whilst unloading.  %sLOCK will fail.\n",
++				trylock ? "TRY" : "");
+ 			/* Don't bother */
+ 			AST_LIST_UNLOCK(&locklist);
+ 			return -1;
+@@ -292,17 +265,12 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 			AST_LIST_UNLOCK(&locklist);
+ 			return -1;
+ 		}
+-		current->requesters = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
+-			NULL, ast_channel_cmp_cb);
+-		if (!current->requesters) {
+-			ast_mutex_destroy(&current->mutex);
+-			ast_cond_destroy(&current->cond);
+-			ast_free(current);
+-			AST_LIST_UNLOCK(&locklist);
+-			return -1;
+-		}
+ 		AST_LIST_INSERT_TAIL(&locklist, current, entries);
+ 	}
++	/* Add to requester list */
++	ast_mutex_lock(&current->mutex);
++	current->requesters++;
++	ast_mutex_unlock(&current->mutex);
+ 	AST_LIST_UNLOCK(&locklist);
+ 
+ 	/* Found lock or created one - now find or create the corresponding link in the channel */
+@@ -315,7 +283,13 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 
+ 	if (!clframe) {
+ 		if (unloading) {
++			ast_log(LOG_ERROR,
++				"Busy unloading.  %sLOCK will fail.\n",
++				trylock ? "TRY" : "");
+ 			/* Don't bother */
++			ast_mutex_lock(&current->mutex);
++			current->requesters--;
++			ast_mutex_unlock(&current->mutex);
+ 			AST_LIST_UNLOCK(list);
+ 			return -1;
+ 		}
+@@ -324,6 +298,9 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 			ast_log(LOG_ERROR,
+ 				"Unable to allocate channel lock frame.  %sLOCK will fail.\n",
+ 				trylock ? "TRY" : "");
++			ast_mutex_lock(&current->mutex);
++			current->requesters--;
++			ast_mutex_unlock(&current->mutex);
+ 			AST_LIST_UNLOCK(list);
+ 			return -1;
+ 		}
+@@ -339,44 +316,44 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 	 * the same amount, before we'll release this one.
+ 	 */
+ 	if (current->owner == chan) {
++		/* We're not a requester, we already have it */
++		ast_mutex_lock(&current->mutex);
++		current->requesters--;
++		ast_mutex_unlock(&current->mutex);
+ 		current->count++;
+ 		return 0;
+ 	}
+ 
+-	/* Okay, we have both frames, so now we need to try to lock.
+-	 *
+-	 * Locking order: always lock locklist first.  We need the
+-	 * locklist lock because the broker thread counts whether
+-	 * there are requesters with the locklist lock held, and we
+-	 * need to hold it, so that when we send our signal, below,
+-	 * to wake up the broker thread, it definitely will see that
+-	 * a requester exists at that point in time.  Otherwise, we
+-	 * could add to the requesters after it has already seen that
+-	 * that lock is unoccupied and wait forever for another signal.
+-	 */
+-	AST_LIST_LOCK(&locklist);
+-	ast_mutex_lock(&current->mutex);
+-	/* Add to requester list */
+-	ao2_link(current->requesters, chan);
+-	pthread_kill(broker_tid, SIGURG);
+-	AST_LIST_UNLOCK(&locklist);
+-
+ 	/* Wait up to three seconds from now for LOCK. */
+ 	now = ast_tvnow();
+ 	timeout.tv_sec = now.tv_sec + 3;
+ 	timeout.tv_nsec = now.tv_usec * 1000;
+ 
+-	if (!current->owner
+-		|| (!trylock
+-			&& !(res = ast_cond_timedwait(&current->cond, &current->mutex, &timeout)))) {
+-		res = 0;
++	ast_mutex_lock(&current->mutex);
++
++	res = 0;
++	while (!trylock && !res && current->owner) {
++		res = ast_cond_timedwait(&current->cond, &current->mutex, &timeout);
++	}
++	if (current->owner) {
++		ast_log(LOG_ERROR, "%sLOCK failed to obtain lock %s.\n", trylock ? "TRY" : "",
++				lockname);
++		/* timeout;
++		 * trylock; or
++		 * cond_timedwait failed.
++		 *
++		 * either way, we fail to obtain the lock.
++		 */
++		res = -1;
++	} else {
+ 		current->owner = chan;
+ 		current->count++;
+-	} else {
+-		res = -1;
++		res = 0;
+ 	}
+ 	/* Remove from requester list */
+-	ao2_unlink(current->requesters, chan);
++	current->requesters--;
++	if (res && unloading)
++		ast_cond_signal(&current->cond);
+ 	ast_mutex_unlock(&current->mutex);
+ 
+ 	return res;
+@@ -400,7 +377,7 @@ static int unlock_read(struct ast_channel *chan, const char *cmd, char *data, ch
+ 	}
+ 
+ 	if (!(list = lock_store->data)) {
+-		ast_debug(1, "This should NEVER happen\n");
++		ast_log(LOG_ERROR, "Datastore's data member is NULL ... this should be impossible.");
+ 		ast_copy_string(buf, "0", len);
+ 		return 0;
+ 	}
+@@ -419,12 +396,17 @@ static int unlock_read(struct ast_channel *chan, const char *cmd, char *data, ch
+ 
+ 	if (!clframe) {
+ 		/* We didn't have this lock in the first place */
++		ast_log(LOG_WARNING, "Attempting to UNLOCK(%s) - a lock this channel never owned.\n",
++				data);
+ 		ast_copy_string(buf, "0", len);
+ 		return 0;
+ 	}
+ 
+ 	if (--clframe->lock_frame->count == 0) {
++		ast_mutex_lock(&clframe->lock_frame->mutex);
+ 		clframe->lock_frame->owner = NULL;
++		ast_cond_signal(&clframe->lock_frame->cond);
++		ast_mutex_unlock(&clframe->lock_frame->mutex);
+ 	}
+ 
+ 	ast_copy_string(buf, "1", len);
+@@ -455,6 +437,37 @@ static int trylock_read(struct ast_channel *chan, const char *cmd, char *data, c
+ 	return 0;
+ }
+ 
++static char *handle_cli_locks_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
++{
++	int c = 0;
++	struct lock_frame* current;
++	switch (cmd) {
++	case CLI_INIT:
++		e->command = "locks show";
++		e->usage =
++			"Usage: locks show\n"
++			"       List all locks known to func_lock, along with their current status.\n";
++		return NULL;
++	case CLI_GENERATE:
++		return NULL;
++	}
++
++	ast_cli(a->fd, "func_lock locks:\n");
++	ast_cli(a->fd, "%-40s Requesters Owner\n", "Name");
++	AST_LIST_LOCK(&locklist);
++	AST_LIST_TRAVERSE(&locklist, current, entries) {
++		ast_mutex_lock(&current->mutex);
++		ast_cli(a->fd, "%-40s %-10d %s\n", current->name, current->requesters,
++				current->owner ? ast_channel_name(current->owner) : "(unlocked)");
++		ast_mutex_unlock(&current->mutex);
++		c++;
++	}
++	AST_LIST_UNLOCK(&locklist);
++	ast_cli(a->fd, "%d total locks listed.\n", c);
++
++	return 0;
++}
++
+ static struct ast_custom_function lock_function = {
+ 	.name = "LOCK",
+ 	.read = lock_read,
+@@ -473,6 +486,8 @@ static struct ast_custom_function unlock_function = {
+ 	.read_max = 2,
+ };
+ 
++static struct ast_cli_entry cli_locks_show = AST_CLI_DEFINE(handle_cli_locks_show, "List func_lock locks.");
++
+ static int unload_module(void)
+ {
+ 	struct lock_frame *current;
+@@ -480,34 +495,43 @@ static int unload_module(void)
+ 	/* Module flag */
+ 	unloading = 1;
+ 
++	/* Make it impossible for new requesters to be added
++	 * NOTE:  channels could already be in get_lock() */
++	ast_custom_function_unregister(&lock_function);
++	ast_custom_function_unregister(&trylock_function);
++
++	ast_cli_unregister(&cli_locks_show);
++
+ 	AST_LIST_LOCK(&locklist);
+ 	while ((current = AST_LIST_REMOVE_HEAD(&locklist, entries))) {
+-		/* If any locks are currently in use, then we cannot unload this module */
+-		if (current->owner || ao2_container_count(current->requesters)) {
+-			/* Put it back */
+-			AST_LIST_INSERT_HEAD(&locklist, current, entries);
+-			AST_LIST_UNLOCK(&locklist);
+-			unloading = 0;
+-			return -1;
++		int warned = 0;
++		ast_mutex_lock(&current->mutex);
++		while (current->owner || current->requesters) {
++			if (!warned) {
++				ast_log(LOG_WARNING, "Waiting for %d requesters for %s lock %s.\n",
++						current->requesters, current->owner ? "locked" : "unlocked",
++						current->name);
++				warned = 1;
++			}
++			/* either the mutex is locked, or other parties are currently in get_lock,
++			 * we need to wait for all of those to clear first */
++			ast_cond_wait(&current->cond, &current->mutex);
+ 		}
++		ast_mutex_unlock(&current->mutex);
++		/* At this point we know:
++		 * 1. the lock has been released,
++		 * 2. there are no requesters (nor should any be able to sneak in).
++		 */
+ 		ast_mutex_destroy(&current->mutex);
+-		ao2_ref(current->requesters, -1);
++		ast_cond_destroy(&current->cond);
+ 		ast_free(current);
+ 	}
++	AST_LIST_UNLOCK(&locklist);
++	AST_LIST_HEAD_DESTROY(&locklist);
+ 
+-	/* No locks left, unregister functions */
+-	ast_custom_function_unregister(&lock_function);
+-	ast_custom_function_unregister(&trylock_function);
++	/* At this point we can safely stop access to UNLOCK */
+ 	ast_custom_function_unregister(&unlock_function);
+ 
+-	if (broker_tid != AST_PTHREADT_NULL) {
+-		pthread_cancel(broker_tid);
+-		pthread_kill(broker_tid, SIGURG);
+-		pthread_join(broker_tid, NULL);
+-	}
+-
+-	AST_LIST_UNLOCK(&locklist);
+-
+ 	return 0;
+ }
+ 
+@@ -516,13 +540,7 @@ static int load_module(void)
+ 	int res = ast_custom_function_register_escalating(&lock_function, AST_CFE_READ);
+ 	res |= ast_custom_function_register_escalating(&trylock_function, AST_CFE_READ);
+ 	res |= ast_custom_function_register_escalating(&unlock_function, AST_CFE_READ);
+-
+-	if (ast_pthread_create_background(&broker_tid, NULL, lock_broker, NULL)) {
+-		ast_log(LOG_ERROR, "Failed to start lock broker thread. Unloading func_lock module.\n");
+-		broker_tid = AST_PTHREADT_NULL;
+-		unload_module();
+-		return AST_MODULE_LOAD_DECLINE;
+-	}
++	res |= ast_cli_register(&cli_locks_show);
+ 
+ 	return res;
+ }
+-- 
+2.26.3
+
diff --git a/net-misc/asterisk/files/asterisk-16.18.0-r1-func_lock-fix-races.patch b/net-misc/asterisk/files/asterisk-16.18.0-r1-func_lock-fix-races.patch
new file mode 100644
index 000000000000..a18ef34d499c
--- /dev/null
+++ b/net-misc/asterisk/files/asterisk-16.18.0-r1-func_lock-fix-races.patch
@@ -0,0 +1,177 @@
+Combined patch from upstream (All authored by myself):
+
+https://gerrit.asterisk.org/c/asterisk/+/15942 (CLI: locks show)
+https://gerrit.asterisk.org/c/asterisk/+/15943 (unload memory corruption)
+https://gerrit.asterisk.org/c/asterisk/+/15944 (error path ref counting)
+https://gerrit.asterisk.org/c/asterisk/+/15945 (ast_module_ref usage)
+
+The cause of my nightmares was the unload memory corruption, however,
+the other two whilst much less likely to occur are just as serious.
+
+Fixes on all has been well tested.  The individual patches are quite small.
+
+Signed-off-by: Jaco Kroon <jaco@uls.co.za>
+---
+diff --git a/funcs/func_lock.c b/funcs/func_lock.c
+index 072640751e..31a7fcda29 100644
+--- a/funcs/func_lock.c
++++ b/funcs/func_lock.c
+@@ -42,6 +42,7 @@
+ #include "asterisk/linkedlists.h"
+ #include "asterisk/astobj2.h"
+ #include "asterisk/utils.h"
++#include "asterisk/cli.h"
+ 
+ /*** DOCUMENTATION
+ 	<function name="LOCK" language="en_US">
+@@ -157,6 +158,8 @@ static void lock_free(void *data)
+ 	AST_LIST_UNLOCK(oldlist);
+ 	AST_LIST_HEAD_DESTROY(oldlist);
+ 	ast_free(oldlist);
++
++	ast_module_unref(ast_module_info->self);
+ }
+ 
+ static void lock_fixup(void *data, struct ast_channel *oldchan, struct ast_channel *newchan)
+@@ -191,7 +194,12 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 	struct timeval now;
+ 
+ 	if (!lock_store) {
+-		ast_debug(1, "Channel %s has no lock datastore, so we're allocating one.\n", ast_channel_name(chan));
++		if (unloading) {
++			ast_log(LOG_ERROR, "%sLOCK has no datastore and func_lock is unloading, failing.\n",
++					trylock ? "TRY" : "");
++			return -1;
++		}
++
+ 		lock_store = ast_datastore_alloc(&lock_info, NULL);
+ 		if (!lock_store) {
+ 			ast_log(LOG_ERROR, "Unable to allocate new datastore.  No locks will be obtained.\n");
+@@ -210,6 +218,9 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 		lock_store->data = list;
+ 		AST_LIST_HEAD_INIT(list);
+ 		ast_channel_datastore_add(chan, lock_store);
++
++		/* We cannot unload until this channel has released the lock_store */
++		ast_module_ref(ast_module_info->self);
+ 	} else
+ 		list = lock_store->data;
+ 
+@@ -223,6 +234,9 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 
+ 	if (!current) {
+ 		if (unloading) {
++			ast_log(LOG_ERROR,
++				"Lock doesn't exist whilst unloading.  %sLOCK will fail.\n",
++				trylock ? "TRY" : "");
+ 			/* Don't bother */
+ 			AST_LIST_UNLOCK(&locklist);
+ 			return -1;
+@@ -249,7 +263,6 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 			AST_LIST_UNLOCK(&locklist);
+ 			return -1;
+ 		}
+-		current->requesters = 0;
+ 		AST_LIST_INSERT_TAIL(&locklist, current, entries);
+ 	}
+ 	/* Add to requester list */
+@@ -268,7 +281,13 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 
+ 	if (!clframe) {
+ 		if (unloading) {
++			ast_log(LOG_ERROR,
++				"Busy unloading.  %sLOCK will fail.\n",
++				trylock ? "TRY" : "");
+ 			/* Don't bother */
++			ast_mutex_lock(&current->mutex);
++			current->requesters--;
++			ast_mutex_unlock(&current->mutex);
+ 			AST_LIST_UNLOCK(list);
+ 			return -1;
+ 		}
+@@ -277,6 +296,9 @@ static int get_lock(struct ast_channel *chan, char *lockname, int trylock)
+ 			ast_log(LOG_ERROR,
+ 				"Unable to allocate channel lock frame.  %sLOCK will fail.\n",
+ 				trylock ? "TRY" : "");
++			ast_mutex_lock(&current->mutex);
++			current->requesters--;
++			ast_mutex_unlock(&current->mutex);
+ 			AST_LIST_UNLOCK(list);
+ 			return -1;
+ 		}
+@@ -409,6 +431,37 @@ static int trylock_read(struct ast_channel *chan, const char *cmd, char *data, c
+ 	return 0;
+ }
+ 
++static char *handle_cli_locks_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
++{
++	int c = 0;
++	struct lock_frame* current;
++	switch (cmd) {
++	case CLI_INIT:
++		e->command = "locks show";
++		e->usage =
++			"Usage: locks show\n"
++			"       List all locks known to func_lock, along with their current status.\n";
++		return NULL;
++	case CLI_GENERATE:
++		return NULL;
++	}
++
++	ast_cli(a->fd, "func_lock locks:\n");
++	ast_cli(a->fd, "%-40s Requesters Owner\n", "Name");
++	AST_LIST_LOCK(&locklist);
++	AST_LIST_TRAVERSE(&locklist, current, entries) {
++		ast_mutex_lock(&current->mutex);
++		ast_cli(a->fd, "%-40s %-10d %s\n", current->name, current->requesters,
++				current->owner ? ast_channel_name(current->owner) : "(unlocked)");
++		ast_mutex_unlock(&current->mutex);
++		c++;
++	}
++	AST_LIST_UNLOCK(&locklist);
++	ast_cli(a->fd, "%d total locks listed.\n", c);
++
++	return 0;
++}
++
+ static struct ast_custom_function lock_function = {
+ 	.name = "LOCK",
+ 	.read = lock_read,
+@@ -427,6 +480,8 @@ static struct ast_custom_function unlock_function = {
+ 	.read_max = 2,
+ };
+ 
++static struct ast_cli_entry cli_locks_show = AST_CLI_DEFINE(handle_cli_locks_show, "List func_lock locks.");
++
+ static int unload_module(void)
+ {
+ 	struct lock_frame *current;
+@@ -439,10 +494,19 @@ static int unload_module(void)
+ 	ast_custom_function_unregister(&lock_function);
+ 	ast_custom_function_unregister(&trylock_function);
+ 
++	ast_cli_unregister(&cli_locks_show);
++
+ 	AST_LIST_LOCK(&locklist);
+-	AST_LIST_TRAVERSE(&locklist, current, entries) {
++	while ((current = AST_LIST_REMOVE_HEAD(&locklist, entries))) {
++		int warned = 0;
+ 		ast_mutex_lock(&current->mutex);
+ 		while (current->owner || current->requesters) {
++			if (!warned) {
++				ast_log(LOG_WARNING, "Waiting for %d requesters for %s lock %s.\n",
++						current->requesters, current->owner ? "locked" : "unlocked",
++						current->name);
++				warned = 1;
++			}
+ 			/* either the mutex is locked, or other parties are currently in get_lock,
+ 			 * we need to wait for all of those to clear first */
+ 			ast_cond_wait(&current->cond, &current->mutex);
+@@ -470,6 +534,7 @@ static int load_module(void)
+ 	int res = ast_custom_function_register_escalating(&lock_function, AST_CFE_READ);
+ 	res |= ast_custom_function_register_escalating(&trylock_function, AST_CFE_READ);
+ 	res |= ast_custom_function_register_escalating(&unlock_function, AST_CFE_READ);
++	res |= ast_cli_register(&cli_locks_show);
+ 
+ 	return res;
+ }