From 1de3325c201dc0e1132bd34ea6f952ff8acbcf80 Mon Sep 17 00:00:00 2001
From: Debarshi Ray <debarshir@freedesktop.org>
Date: Fri, 16 Sep 2016 08:41:48 +0200
Subject: [PATCH 2/2] Remove all queues before
dleyna_task_processor_t->on_quit_cb is run
If dleyna_task_processor_t->on_quit_cb is run while there are still
queues present in the processor, it can lead to a crash if one of the
queue's task_queue_finally_cb handler didn't expect to be run after
the control point has been stopped. For example,
dleyna-renderer-service crashes with this backtrace:
%0 __GI_raise (sig=sig@entry=6)
at ../sysdeps/unix/sysv/linux/raise.c:54
%1 __GI_abort () at abort.c:89
%2 g_assertion_message (domain="GLib",
file="ghash.c",
line=373,
func="g_hash_table_lookup_node",
message="assertion failed:
(hash_table->ref_count > 0)")
at gtestutils.c:2429
%3 g_assertion_message_expr (domain="GLib",
file="ghash.c",
line=373,
func="g_hash_table_lookup_node",
expr="hash_table->ref_count > 0")
at gtestutils.c:2452
%4 g_hash_table_lookup_node (hash_return=<synthetic pointer>,
key=0x561e98ca21c0,
hash_table=0x561e985899e0)
at ghash.c:373
%5 g_hash_table_insert_internal (hash_table=0x561e985899e0,
key=0x561e98ca21c0,
value=0x561e98a581f0,
keep_new_key=0)
at ghash.c:1227
%6 prv_device_chain_end (cancelled=<optimized out>,
data=0x561e98e3acb0)
at upnp.c:85
%7 prv_free_cb (data=0x561e98b97280)
at libdleyna/core/task-processor.c:103
%8 g_hash_table_remove_all_nodes (hash_table=0x561e98549240,
notify=<optimized out>,
destruction=<optimized out>)
at ghash.c:548
%9 g_hash_table_remove_all_nodes (destruction=1,
notify=1,
hash_table=0x561e98549240)
at ghash.c:1093
%10 g_hash_table_unref (hash_table=0x561e98549240) at ghash.c:1097
%11 dleyna_task_processor_free (processor=0x561e985543a0)
at libdleyna/core/task-processor.c:136
%12 prv_context_free () at libdleyna/core/main-loop.c:108
%13 dleyna_main_loop_start (server=<optimized out>,
control_point=<optimized out>,
user_data=0x0)
at libdleyna/core/main-loop.c:167
%14 __libc_start_main (main=0x561e97db5990 <main>,
argc=1,
argv=0x7fff905cb0a8,
init=<optimized out>,
fini=<optimized out>,
rtld_fini=<optimized out>,
stack_end=0x7fff905cb098)
at ../csu/libc-start.c:289
%15 _start ()
The processor's on_quit_cb handler is set to prv_context_quit_cb,
which calls control_point->stop_service and quits the GMainLoop. Then
the processor is destroyed, which in turn destroys any queues that
might have been left inside it. Unfortunately, a queue's
task_queue_finally_cb handler might be set to something that assumes
that the control_point has not been stopped. For example,
dleyna-renderer-service sets task_queue_finally_cb to
prv_device_chain_end, which will crash due to accessing invalid memory
(specifically the dlr_upnp_t) if prv_control_point_stop_service has
already been invoked. We see the same problem in dleyna-server-service
too.
Therefore, let's remove any leftover queues from the processor just
before dleyna_task_processor_t->on_quit_cb is scheduled to run. We are
about to terminate the process anyway, so it shouldn't hurt to do it
slightly earlier in the sequence.
https://bugzilla.redhat.com/show_bug.cgi?id=1360209
---
libdleyna/core/task-processor.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/libdleyna/core/task-processor.c b/libdleyna/core/task-processor.c
index 6d7f5b87de3d..89f0386c3f98 100644
--- a/libdleyna/core/task-processor.c
+++ b/libdleyna/core/task-processor.c
@@ -257,6 +257,7 @@ void dleyna_task_processor_set_quitting(dleyna_task_processor_t *processor)
g_idle_add(processor->on_quit_cb, NULL);
prv_cancel_all_queues(processor);
+ g_hash_table_remove_all(processor->task_queues);
DLEYNA_LOG_DEBUG("Exit");
}
@@ -460,6 +461,7 @@ void dleyna_task_queue_task_completed(const dleyna_task_queue_key_t *queue_id)
if (processor->quitting && !processor->running_tasks) {
g_idle_add(processor->on_quit_cb, NULL);
+ g_hash_table_remove_all(processor->task_queues);
} else if (queue->defer_remove) {
DLEYNA_LOG_DEBUG("Removing queue <%s,%s>",
queue_id->source, queue_id->sink);
--
2.7.4