gstreamer/plugins/tracers/gstleaks.c
Matthew Waters 15761c93c2 tracers/leaks: fix reentrancy issues with the custom signal handlers
The signal handlers were performing mutex operations in the signal handlers
which is bad idea that may lead to deadlocks.

1. Implement a separate signal thread to handle the signals.
2. Use the glib provided signal GSource to avoid performing operations in
   the signal handler.

Fix #186

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/487>
2020-06-09 12:36:18 +00:00

1269 lines
38 KiB
C

/* GStreamer
* Copyright (C) 2016 Collabora Ltd. <guillaume.desmottes@collabora.co.uk>
* Copyright (C) 2019 Nirbheek Chauhan <nirbheek@centricular.com>
*
* gstleaks.c: tracing module detecting object leaks
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:tracer-leaks
* @short_description: detect GstObject and GstMiniObject leaks
*
* This tracing module tracks the lifetimes of #GstObject and #GstMiniObject
* objects and prints a list of leaks to the debug log under `GST_TRACER:7` when
* gst_deinit() is called, and also prints a g_warning().
*
* Starting with GStreamer 1.18, you can also use action signals on the tracer
* object to fetch leak information. Use gst_tracing_get_active_tracers() to
* get a list of all active tracers and find the right one by name.
*
* You can activate this tracer in the usual way by adding the string 'leaks'
* to the environment variable `GST_TRACERS`. Such as: `GST_TRACERS=leaks`
*
* Note that the values are separated by semicolon (`;`), such as:
* `GST_TRACERS=leaks;latency`, and multiple instances of the same tracer can be
* active at the same time.
*
* Parameters can also be passed to each tracer. The leaks tracer currently
* accepts five params:
* 1. filters: (string) to filter which objects to record
* 2. check-refs: (boolean) whether to record every location where a leaked
* object was reffed and unreffed
* 3. stack-traces-flags: (string) full or none; see: #GstStackTraceFlags
* 4. name: (string) set a name for the tracer object itself
* 5. log-leaks-on-deinit: (boolean) whether to report all leaks on
* gst_deinit() by printing them in the debug log; "true" by default
*
* Examples:
* ```
* GST_TRACERS='leaks(filters="GstEvent,GstMessage",stack-traces-flags=none)'
* ```
* ```
* GST_TRACERS='leaks(filters="GstBuffer",stack-traces-flags=full,check-refs=true);leaks(name=all-leaks)'
* ```
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "gstleaks.h"
#ifdef G_OS_UNIX
#include <glib-unix.h>
#include <pthread.h>
#endif /* G_OS_UNIX */
GST_DEBUG_CATEGORY_STATIC (gst_leaks_debug);
#define GST_CAT_DEFAULT gst_leaks_debug
enum
{
/* actions */
SIGNAL_GET_LIVE_OBJECTS,
SIGNAL_LOG_LIVE_OBJECTS,
SIGNAL_ACTIVITY_START_TRACKING,
SIGNAL_ACTIVITY_GET_CHECKPOINT,
SIGNAL_ACTIVITY_LOG_CHECKPOINT,
SIGNAL_ACTIVITY_STOP_TRACKING,
LAST_SIGNAL
};
#define DEFAULT_LOG_LEAKS TRUE /* for backwards-compat */
#define _do_init \
GST_DEBUG_CATEGORY_INIT (gst_leaks_debug, "leaks", 0, "leaks tracer");
#define gst_leaks_tracer_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstLeaksTracer, gst_leaks_tracer,
GST_TYPE_TRACER, _do_init);
static GstStructure *gst_leaks_tracer_get_live_objects (GstLeaksTracer * self);
static void gst_leaks_tracer_log_live_objects (GstLeaksTracer * self);
static void gst_leaks_tracer_activity_start_tracking (GstLeaksTracer * self);
static GstStructure *gst_leaks_tracer_activity_get_checkpoint (GstLeaksTracer *
self);
static void gst_leaks_tracer_activity_log_checkpoint (GstLeaksTracer * self);
static void gst_leaks_tracer_activity_stop_tracking (GstLeaksTracer * self);
#ifdef G_OS_UNIX
static void gst_leaks_tracer_setup_signals (GstLeaksTracer * leaks);
static void gst_leaks_tracer_cleanup_signals (GstLeaksTracer * leaks);
#endif
static GstTracerRecord *tr_alive;
static GstTracerRecord *tr_refings;
static GstTracerRecord *tr_added = NULL;
static GstTracerRecord *tr_removed = NULL;
static GQueue instances = G_QUEUE_INIT;
static guint gst_leaks_tracer_signals[LAST_SIGNAL] = { 0 };
G_LOCK_DEFINE_STATIC (instances);
typedef struct
{
gboolean reffed;
gchar *trace;
gint new_refcount;
GstClockTime ts;
} ObjectRefingInfo;
typedef struct
{
gchar *creation_trace;
GList *refing_infos;
} ObjectRefingInfos;
static void
object_refing_info_free (ObjectRefingInfo * refinfo)
{
g_free (refinfo->trace);
g_free (refinfo);
}
static void
object_refing_infos_free (ObjectRefingInfos * infos)
{
g_list_free_full (infos->refing_infos,
(GDestroyNotify) object_refing_info_free);
g_free (infos->creation_trace);
g_free (infos);
}
static void
set_print_stack_trace_from_string (GstLeaksTracer * self, const gchar * str)
{
gchar *trace;
/* Test if we can retrieve backtrace */
trace = gst_debug_get_stack_trace (FALSE);
if (!trace)
return;
g_free (trace);
if (g_strcmp0 (str, "full") == 0)
self->trace_flags = GST_STACK_TRACE_SHOW_FULL;
else
self->trace_flags = GST_STACK_TRACE_SHOW_NONE;
}
static void
set_print_stack_trace (GstLeaksTracer * self, GstStructure * params)
{
const gchar *trace_flags = g_getenv ("GST_LEAKS_TRACER_STACK_TRACE");
self->trace_flags = -1;
if (!trace_flags && params)
trace_flags = gst_structure_get_string (params, "stack-traces-flags");
if (!trace_flags)
return;
set_print_stack_trace_from_string (self, trace_flags);
}
static void
set_filters (GstLeaksTracer * self, const gchar * filters)
{
guint i;
GStrv tmp = g_strsplit (filters, ",", -1);
self->filter = g_array_sized_new (FALSE, FALSE, sizeof (GType),
g_strv_length (tmp));
for (i = 0; tmp[i]; i++) {
GType type;
type = g_type_from_name (tmp[i]);
if (type == 0) {
/* The type may not yet be known by the type system, typically because
* the plugin implementing it as not yet be loaded. Save it for now as
* it will have another chance to be added to the filter later in
* should_handle_object_type() when/if the object type is actually
* used. */
if (!self->unhandled_filter)
self->unhandled_filter = g_hash_table_new_full (g_str_hash, g_str_equal,
g_free, NULL);
g_hash_table_add (self->unhandled_filter, g_strdup (tmp[i]));
g_atomic_int_inc (&self->unhandled_filter_count);
continue;
}
GST_DEBUG_OBJECT (self, "add filter on %s", tmp[i]);
g_array_append_val (self->filter, type);
}
g_strfreev (tmp);
}
static void
set_params_from_structure (GstLeaksTracer * self, GstStructure * params)
{
const gchar *filters, *name;
filters = gst_structure_get_string (params, "filters");
if (filters)
set_filters (self, filters);
name = gst_structure_get_string (params, "name");
if (name)
gst_object_set_name (GST_OBJECT (self), name);
gst_structure_get_boolean (params, "check-refs", &self->check_refs);
gst_structure_get_boolean (params, "log-leaks-on-deinit", &self->log_leaks);
}
static void
set_params (GstLeaksTracer * self)
{
gchar *params, *tmp;
GstStructure *params_struct = NULL;
g_object_get (self, "params", &params, NULL);
if (!params)
goto set_stacktrace;
tmp = g_strdup_printf ("leaks,%s", params);
params_struct = gst_structure_from_string (tmp, NULL);
g_free (tmp);
if (params_struct)
set_params_from_structure (self, params_struct);
else
set_filters (self, params);
g_free (params);
set_stacktrace:
set_print_stack_trace (self, params_struct);
if (params_struct)
gst_structure_free (params_struct);
}
static gboolean
_expand_unhandled_filters (gchar * typename, gpointer unused_value,
GstLeaksTracer * self)
{
GType type;
type = g_type_from_name (typename);
if (type == 0)
return FALSE;
g_atomic_int_dec_and_test (&self->unhandled_filter_count);
g_array_append_val (self->filter, type);
return TRUE;
}
static gboolean
should_handle_object_type (GstLeaksTracer * self, GType object_type)
{
guint i, len;
if (!self->filter)
/* No filtering, handle all types */
return TRUE;
if (object_type == 0)
return FALSE;
if (g_atomic_int_get (&self->unhandled_filter_count)) {
GST_OBJECT_LOCK (self);
g_hash_table_foreach_remove (self->unhandled_filter,
(GHRFunc) _expand_unhandled_filters, self);
GST_OBJECT_UNLOCK (self);
}
len = self->filter->len;
for (i = 0; i < len; i++) {
GType type = g_array_index (self->filter, GType, i);
if (g_type_is_a (object_type, type))
return TRUE;
}
return FALSE;
}
/* The object may be destroyed when we log it using the checkpointing system so
* we have to save its type name */
typedef struct
{
gpointer object;
const gchar *type_name;
} ObjectLog;
static ObjectLog *
object_log_new (gpointer obj)
{
ObjectLog *o = g_new (ObjectLog, 1);
o->object = obj;
if (G_IS_OBJECT (obj))
o->type_name = G_OBJECT_TYPE_NAME (obj);
else
o->type_name = g_type_name (GST_MINI_OBJECT_TYPE (obj));
return o;
}
static void
object_log_free (ObjectLog * obj)
{
g_free (obj);
}
static void
handle_object_destroyed (GstLeaksTracer * self, gpointer object)
{
GST_OBJECT_LOCK (self);
if (self->done) {
g_warning
("object %p destroyed while the leaks tracer was finalizing. Some threads are still running?",
object);
goto out;
}
g_hash_table_remove (self->objects, object);
if (self->removed)
g_hash_table_add (self->removed, object_log_new (object));
out:
GST_OBJECT_UNLOCK (self);
}
static void
object_weak_cb (gpointer data, GObject * object)
{
GstLeaksTracer *self = data;
handle_object_destroyed (self, object);
}
static void
mini_object_weak_cb (gpointer data, GstMiniObject * object)
{
GstLeaksTracer *self = data;
handle_object_destroyed (self, object);
}
static void
handle_object_created (GstLeaksTracer * self, gpointer object, GType type,
gboolean gobject)
{
ObjectRefingInfos *infos;
if (!should_handle_object_type (self, type))
return;
infos = g_malloc0 (sizeof (ObjectRefingInfos));
if (gobject)
g_object_weak_ref ((GObject *) object, object_weak_cb, self);
else
gst_mini_object_weak_ref (GST_MINI_OBJECT_CAST (object),
mini_object_weak_cb, self);
GST_OBJECT_LOCK (self);
if ((gint) self->trace_flags != -1)
infos->creation_trace = gst_debug_get_stack_trace (self->trace_flags);
g_hash_table_insert (self->objects, object, infos);
if (self->added)
g_hash_table_add (self->added, object_log_new (object));
GST_OBJECT_UNLOCK (self);
}
static void
mini_object_created_cb (GstTracer * tracer, GstClockTime ts,
GstMiniObject * object)
{
GstLeaksTracer *self = GST_LEAKS_TRACER_CAST (tracer);
handle_object_created (self, object, GST_MINI_OBJECT_TYPE (object), FALSE);
}
static void
object_created_cb (GstTracer * tracer, GstClockTime ts, GstObject * object)
{
GstLeaksTracer *self = GST_LEAKS_TRACER_CAST (tracer);
GType object_type = G_OBJECT_TYPE (object);
/* Can't track tracers as they may be disposed after the leak tracer itself */
if (g_type_is_a (object_type, GST_TYPE_TRACER))
return;
handle_object_created (self, object, object_type, TRUE);
}
static void
handle_object_reffed (GstLeaksTracer * self, gpointer object, GType type,
gint new_refcount, gboolean reffed, GstClockTime ts)
{
ObjectRefingInfos *infos;
ObjectRefingInfo *refinfo;
if (!self->check_refs)
return;
if (!should_handle_object_type (self, type))
return;
GST_OBJECT_LOCK (self);
infos = g_hash_table_lookup (self->objects, object);
if (!infos)
goto out;
refinfo = g_malloc0 (sizeof (ObjectRefingInfo));
refinfo->ts = ts;
refinfo->new_refcount = new_refcount;
refinfo->reffed = reffed;
if ((gint) self->trace_flags != -1)
refinfo->trace = gst_debug_get_stack_trace (self->trace_flags);
infos->refing_infos = g_list_prepend (infos->refing_infos, refinfo);
out:
GST_OBJECT_UNLOCK (self);
}
static void
object_reffed_cb (GstTracer * tracer, GstClockTime ts, GstObject * object,
gint new_refcount)
{
GstLeaksTracer *self = GST_LEAKS_TRACER_CAST (tracer);
handle_object_reffed (self, object, G_OBJECT_TYPE (object), new_refcount,
TRUE, ts);
}
static void
object_unreffed_cb (GstTracer * tracer, GstClockTime ts, GstObject * object,
gint new_refcount)
{
GstLeaksTracer *self = GST_LEAKS_TRACER_CAST (tracer);
handle_object_reffed (self, object, G_OBJECT_TYPE (object), new_refcount,
FALSE, ts);
}
static void
mini_object_reffed_cb (GstTracer * tracer, GstClockTime ts,
GstMiniObject * object, gint new_refcount)
{
GstLeaksTracer *self = GST_LEAKS_TRACER_CAST (tracer);
handle_object_reffed (self, object, GST_MINI_OBJECT_TYPE (object),
new_refcount, TRUE, ts);
}
static void
mini_object_unreffed_cb (GstTracer * tracer, GstClockTime ts,
GstMiniObject * object, gint new_refcount)
{
GstLeaksTracer *self = GST_LEAKS_TRACER_CAST (tracer);
handle_object_reffed (self, object, GST_MINI_OBJECT_TYPE (object),
new_refcount, FALSE, ts);
}
static void
gst_leaks_tracer_init (GstLeaksTracer * self)
{
self->log_leaks = DEFAULT_LOG_LEAKS;
self->objects = g_hash_table_new_full (NULL, NULL, NULL,
(GDestroyNotify) object_refing_infos_free);
if (g_getenv ("GST_LEAKS_TRACER_SIG")) {
#ifdef G_OS_UNIX
gst_leaks_tracer_setup_signals (self);
#else
g_warning ("System doesn't support POSIX signals");
#endif /* G_OS_UNIX */
}
G_LOCK (instances);
g_queue_push_tail (&instances, self);
G_UNLOCK (instances);
}
static void
gst_leaks_tracer_constructed (GObject * object)
{
GstLeaksTracer *self = GST_LEAKS_TRACER (object);
GstTracer *tracer = GST_TRACER (object);
set_params (self);
gst_tracing_register_hook (tracer, "mini-object-created",
G_CALLBACK (mini_object_created_cb));
gst_tracing_register_hook (tracer, "object-created",
G_CALLBACK (object_created_cb));
if (self->check_refs) {
gst_tracing_register_hook (tracer, "object-reffed",
G_CALLBACK (object_reffed_cb));
gst_tracing_register_hook (tracer, "mini-object-reffed",
G_CALLBACK (mini_object_reffed_cb));
gst_tracing_register_hook (tracer, "mini-object-unreffed",
G_CALLBACK (mini_object_unreffed_cb));
gst_tracing_register_hook (tracer, "object-unreffed",
G_CALLBACK (object_unreffed_cb));
}
/* We rely on weak pointers rather than (mini-)object-destroyed hooks so we
* are notified of objects being destroyed even during the shuting down of
* the tracing system. */
((GObjectClass *) gst_leaks_tracer_parent_class)->constructed (object);
}
typedef struct
{
gpointer obj;
GType type;
guint ref_count;
gchar *desc;
ObjectRefingInfos *infos;
} Leak;
/* The content of the returned Leak struct is valid until the self->objects
* hash table has been modified. */
static Leak *
leak_new (gpointer obj, GType type, guint ref_count, ObjectRefingInfos * infos)
{
Leak *leak = g_new (Leak, 1);
leak->obj = obj;
leak->type = type;
leak->ref_count = ref_count;
leak->desc = gst_info_strdup_printf ("%" GST_PTR_FORMAT, obj);
leak->infos = infos;
return leak;
}
static void
leak_free (Leak * leak)
{
g_free (leak->desc);
g_free (leak);
}
static gint
sort_leaks (gconstpointer _a, gconstpointer _b)
{
const Leak *a = _a, *b = _b;
return g_strcmp0 (g_type_name (a->type), g_type_name (b->type));
}
static GList *
create_leaks_list (GstLeaksTracer * self)
{
GList *l = NULL;
GHashTableIter iter;
gpointer obj, infos;
g_hash_table_iter_init (&iter, self->objects);
while (g_hash_table_iter_next (&iter, &obj, &infos)) {
GType type;
guint ref_count;
if (GST_IS_OBJECT (obj)) {
if (GST_OBJECT_FLAG_IS_SET (obj, GST_OBJECT_FLAG_MAY_BE_LEAKED))
continue;
type = G_OBJECT_TYPE (obj);
ref_count = ((GObject *) obj)->ref_count;
} else {
if (GST_MINI_OBJECT_FLAG_IS_SET (obj, GST_MINI_OBJECT_FLAG_MAY_BE_LEAKED))
continue;
type = GST_MINI_OBJECT_TYPE (obj);
ref_count = ((GstMiniObject *) obj)->refcount;
}
l = g_list_prepend (l, leak_new (obj, type, ref_count, infos));
}
/* Sort leaks by type name so they are grouped together making the output
* easier to read */
l = g_list_sort (l, sort_leaks);
/* Reverse list to sort objects by creation time; this is needed because we
* prepended objects into this list earlier, and because g_list_sort() above
* is stable so the creation order is preserved when sorting by type name. */
return g_list_reverse (l);
}
static void
process_leak (Leak * leak, GValue * ret_leaks)
{
GstStructure *r, *s = NULL;
GList *ref;
GValue refings = G_VALUE_INIT;
if (!ret_leaks) {
/* log to the debug log */
gst_tracer_record_log (tr_alive, g_type_name (leak->type), leak->obj,
leak->desc, leak->ref_count,
leak->infos->creation_trace ? leak->infos->creation_trace : "");
} else {
GValue s_value = G_VALUE_INIT;
GValue obj_value = G_VALUE_INIT;
/* for leaked objects, we take ownership of the object instead of
* reffing ("collecting") it to avoid deadlocks */
g_value_init (&obj_value, leak->type);
if (GST_IS_OBJECT (leak->obj))
g_value_take_object (&obj_value, leak->obj);
else
/* mini objects */
g_value_take_boxed (&obj_value, leak->obj);
s = gst_structure_new_empty ("object-alive");
gst_structure_take_value (s, "object", &obj_value);
gst_structure_set (s, "ref-count", G_TYPE_UINT, leak->ref_count,
"trace", G_TYPE_STRING, leak->infos->creation_trace, NULL);
/* avoid copy of structure */
g_value_init (&s_value, GST_TYPE_STRUCTURE);
g_value_take_boxed (&s_value, s);
gst_value_list_append_and_take_value (ret_leaks, &s_value);
}
/* store refinfo if available */
if (leak->infos->refing_infos)
g_value_init (&refings, GST_TYPE_LIST);
/* iterate the list from last to first to correct the order */
for (ref = g_list_last (leak->infos->refing_infos); ref; ref = ref->prev) {
ObjectRefingInfo *refinfo = (ObjectRefingInfo *) ref->data;
if (!ret_leaks) {
/* log to the debug log */
gst_tracer_record_log (tr_refings, refinfo->ts, g_type_name (leak->type),
leak->obj, refinfo->reffed ? "reffed" : "unreffed",
refinfo->new_refcount, refinfo->trace ? refinfo->trace : "");
} else {
GValue r_value = G_VALUE_INIT;
r = gst_structure_new_empty ("object-refings");
gst_structure_set (r, "ts", GST_TYPE_CLOCK_TIME, refinfo->ts,
"desc", G_TYPE_STRING, refinfo->reffed ? "reffed" : "unreffed",
"ref-count", G_TYPE_UINT, refinfo->new_refcount,
"trace", G_TYPE_STRING, refinfo->trace, NULL);
/* avoid copy of structure */
g_value_init (&r_value, GST_TYPE_STRUCTURE);
g_value_take_boxed (&r_value, r);
gst_value_list_append_and_take_value (&refings, &r_value);
}
}
if (ret_leaks && leak->infos->refing_infos)
gst_structure_take_value (s, "ref-infos", &refings);
}
/* Return TRUE if at least one leaked object was found */
static gboolean
process_leaks (GstLeaksTracer * self, GValue * ret_leaks)
{
GList *leaks, *l;
gboolean ret = FALSE;
if (!ret_leaks)
GST_TRACE_OBJECT (self, "start listing currently alive objects");
leaks = create_leaks_list (self);
if (!leaks) {
if (!ret_leaks)
GST_TRACE_OBJECT (self, "No objects alive currently");
goto done;
}
for (l = leaks; l; l = l->next)
process_leak (l->data, ret_leaks);
g_list_free_full (leaks, (GDestroyNotify) leak_free);
ret = TRUE;
done:
if (!ret_leaks)
GST_TRACE_OBJECT (self, "done listing currently alive objects");
return ret;
}
static void
gst_leaks_tracer_finalize (GObject * object)
{
GstLeaksTracer *self = GST_LEAKS_TRACER (object);
gboolean leaks = FALSE;
GHashTableIter iter;
gpointer obj;
self->done = TRUE;
/* Tracers are destroyed as part of gst_deinit() so now is a good time to
* report all the objects which are still alive. */
if (self->log_leaks)
leaks = process_leaks (self, NULL);
/* Remove weak references */
g_hash_table_iter_init (&iter, self->objects);
while (g_hash_table_iter_next (&iter, &obj, NULL)) {
if (GST_IS_OBJECT (obj))
g_object_weak_unref (obj, object_weak_cb, self);
else
gst_mini_object_weak_unref (GST_MINI_OBJECT_CAST (obj),
mini_object_weak_cb, self);
}
g_clear_pointer (&self->objects, g_hash_table_unref);
if (self->filter)
g_array_free (self->filter, TRUE);
g_clear_pointer (&self->added, g_hash_table_unref);
g_clear_pointer (&self->removed, g_hash_table_unref);
g_clear_pointer (&self->unhandled_filter, g_hash_table_unref);
G_LOCK (instances);
g_queue_remove (&instances, self);
G_UNLOCK (instances);
#ifdef G_OS_UNIX
gst_leaks_tracer_cleanup_signals (self);
#endif
if (leaks)
g_warning ("Leaks detected and logged under GST_DEBUG=GST_TRACER:7");
((GObjectClass *) gst_leaks_tracer_parent_class)->finalize (object);
}
#define RECORD_FIELD_TYPE_TS \
"ts", GST_TYPE_STRUCTURE, gst_structure_new ("value", \
"type", G_TYPE_GTYPE, GST_TYPE_CLOCK_TIME, \
NULL)
#define RECORD_FIELD_TYPE_NAME \
"type-name", GST_TYPE_STRUCTURE, gst_structure_new ("value", \
"type", G_TYPE_GTYPE, G_TYPE_STRING, \
NULL)
#define RECORD_FIELD_ADDRESS \
"address", GST_TYPE_STRUCTURE, gst_structure_new ("value", \
"type", G_TYPE_GTYPE, G_TYPE_POINTER, \
NULL)
#define RECORD_FIELD_DESC \
"description", GST_TYPE_STRUCTURE, gst_structure_new ("value", \
"type", G_TYPE_GTYPE, G_TYPE_STRING, \
NULL)
#define RECORD_FIELD_REF_COUNT \
"ref-count", GST_TYPE_STRUCTURE, gst_structure_new ("value", \
"type", G_TYPE_GTYPE, G_TYPE_UINT, \
NULL)
#define RECORD_FIELD_TRACE \
"trace", GST_TYPE_STRUCTURE, gst_structure_new ("value", \
"type", G_TYPE_GTYPE, G_TYPE_STRING, \
NULL)
#ifdef G_OS_UNIX
static gboolean
sig_usr1_handler (gpointer data)
{
G_LOCK (instances);
g_queue_foreach (&instances, (GFunc) gst_leaks_tracer_log_live_objects, NULL);
G_UNLOCK (instances);
return G_SOURCE_CONTINUE;
}
static void
sig_usr2_handler_foreach (gpointer data, gpointer user_data)
{
GstLeaksTracer *tracer = data;
if (!tracer->added) {
GST_TRACE_OBJECT (tracer, "First checkpoint, start tracking objects");
gst_leaks_tracer_activity_start_tracking (tracer);
} else {
gst_leaks_tracer_activity_log_checkpoint (tracer);
}
}
static gboolean
sig_usr2_handler (gpointer data)
{
G_LOCK (instances);
g_queue_foreach (&instances, sig_usr2_handler_foreach, NULL);
G_UNLOCK (instances);
return G_SOURCE_CONTINUE;
}
struct signal_thread_data
{
GMutex lock;
GCond cond;
gboolean ready;
};
static GMainLoop *signal_loop; /* NULL */
static GThread *signal_thread; /* NULL */
static gint signal_thread_users; /* 0 */
G_LOCK_DEFINE_STATIC (signal_thread);
static gboolean
unlock_mutex (gpointer data)
{
g_mutex_unlock ((GMutex *) data);
return G_SOURCE_REMOVE;
}
static gpointer
gst_leaks_tracer_signal_thread (struct signal_thread_data *data)
{
static GMainContext *signal_ctx;
GSource *source1, *source2, *unlock_source;
signal_ctx = g_main_context_new ();
signal_loop = g_main_loop_new (signal_ctx, FALSE);
unlock_source = g_idle_source_new ();
g_source_set_callback (unlock_source, unlock_mutex, &data->lock, NULL);
g_source_attach (unlock_source, signal_ctx);
source1 = g_unix_signal_source_new (SIGUSR1);
g_source_set_callback (source1, sig_usr1_handler, NULL, NULL);
g_source_attach (source1, signal_ctx);
source2 = g_unix_signal_source_new (SIGUSR2);
g_source_set_callback (source2, sig_usr2_handler, NULL, NULL);
g_source_attach (source2, signal_ctx);
g_mutex_lock (&data->lock);
data->ready = TRUE;
g_cond_broadcast (&data->cond);
g_main_loop_run (signal_loop);
g_source_destroy (source1);
g_source_destroy (source2);
g_main_loop_unref (signal_loop);
signal_loop = NULL;
g_main_context_unref (signal_ctx);
signal_ctx = NULL;
return NULL;
}
static void
atfork_prepare (void)
{
G_LOCK (signal_thread);
}
static void
atfork_parent (void)
{
G_UNLOCK (signal_thread);
}
static void
atfork_child (void)
{
signal_thread_users = 0;
signal_thread = NULL;
G_UNLOCK (signal_thread);
}
static void
gst_leaks_tracer_setup_signals (GstLeaksTracer * leaks)
{
struct signal_thread_data data;
G_LOCK (signal_thread);
signal_thread_users++;
if (signal_thread_users == 1) {
gint res;
GST_INFO_OBJECT (leaks, "Setting up signal handling");
/* If application is forked, the child process won't inherit the extra thread.
* As a result we need to reset the child process thread state accordingly.
* This is typically needed when running tests as libcheck fork the tests.
*
* See https://pubs.opengroup.org/onlinepubs/007904975/functions/pthread_atfork.html
* for details. */
res = pthread_atfork (atfork_prepare, atfork_parent, atfork_child);
if (!res) {
GST_WARNING_OBJECT (leaks, "pthread_atfork() failed (%d)", res);
}
data.ready = FALSE;
g_mutex_init (&data.lock);
g_cond_init (&data.cond);
signal_thread = g_thread_new ("gstleak-signal",
(GThreadFunc) gst_leaks_tracer_signal_thread, &data);
g_mutex_lock (&data.lock);
while (!data.ready)
g_cond_wait (&data.cond, &data.lock);
g_mutex_unlock (&data.lock);
g_mutex_clear (&data.lock);
g_cond_clear (&data.cond);
}
G_UNLOCK (signal_thread);
}
static void
gst_leaks_tracer_cleanup_signals (GstLeaksTracer * leaks)
{
G_LOCK (signal_thread);
signal_thread_users--;
if (signal_thread_users == 0) {
GST_INFO_OBJECT (leaks, "Cleaning up signal handling");
g_main_loop_quit (signal_loop);
g_thread_join (signal_thread);
signal_thread = NULL;
gst_object_unref (tr_added);
tr_added = NULL;
gst_object_unref (tr_removed);
tr_removed = NULL;
}
G_UNLOCK (signal_thread);
}
#else
#define setup_signals() g_warning ("System doesn't support POSIX signals");
#endif /* G_OS_UNIX */
static GstStructure *
gst_leaks_tracer_get_live_objects (GstLeaksTracer * self)
{
GstStructure *info;
GValue live_objects = G_VALUE_INIT;
g_value_init (&live_objects, GST_TYPE_LIST);
GST_OBJECT_LOCK (self);
process_leaks (self, &live_objects);
GST_OBJECT_UNLOCK (self);
info = gst_structure_new_empty ("live-objects-info");
gst_structure_take_value (info, "live-objects-list", &live_objects);
return info;
}
static void
gst_leaks_tracer_log_live_objects (GstLeaksTracer * self)
{
GST_OBJECT_LOCK (self);
process_leaks (self, NULL);
GST_OBJECT_UNLOCK (self);
}
static void
gst_leaks_tracer_activity_start_tracking (GstLeaksTracer * self)
{
GST_OBJECT_LOCK (self);
if (self->added) {
GST_ERROR_OBJECT (self, "tracking is already in progress");
return;
}
self->added = g_hash_table_new_full (NULL, NULL,
(GDestroyNotify) object_log_free, NULL);
self->removed = g_hash_table_new_full (NULL, NULL,
(GDestroyNotify) object_log_free, NULL);
GST_OBJECT_UNLOCK (self);
}
/* When @ret is %NULL, this simply logs the activities */
static void
process_checkpoint (GstTracerRecord * record, const gchar * record_type,
GHashTable * hash, GValue * ret)
{
GHashTableIter iter;
gpointer o;
g_hash_table_iter_init (&iter, hash);
while (g_hash_table_iter_next (&iter, &o, NULL)) {
ObjectLog *obj = o;
if (!ret) {
/* log to the debug log */
gst_tracer_record_log (record, obj->type_name, obj->object);
} else {
GValue s_value = G_VALUE_INIT;
GValue addr_value = G_VALUE_INIT;
gchar *address = g_strdup_printf ("%p", obj->object);
GstStructure *s = gst_structure_new_empty (record_type);
/* copy type_name because it's owned by @obj */
gst_structure_set (s, "type-name", G_TYPE_STRING, obj->type_name, NULL);
/* avoid copy of @address */
g_value_init (&addr_value, G_TYPE_STRING);
g_value_take_string (&addr_value, address);
gst_structure_take_value (s, "address", &addr_value);
/* avoid copy of the structure */
g_value_init (&s_value, GST_TYPE_STRUCTURE);
g_value_take_boxed (&s_value, s);
gst_value_list_append_and_take_value (ret, &s_value);
}
}
}
static GstStructure *
gst_leaks_tracer_activity_get_checkpoint (GstLeaksTracer * self)
{
GValue added = G_VALUE_INIT;
GValue removed = G_VALUE_INIT;
GstStructure *s = gst_structure_new_empty ("activity-checkpoint");
g_value_init (&added, GST_TYPE_LIST);
g_value_init (&removed, GST_TYPE_LIST);
GST_OBJECT_LOCK (self);
process_checkpoint (tr_added, "objects-created", self->added, &added);
process_checkpoint (tr_removed, "objects-removed", self->removed, &removed);
g_hash_table_remove_all (self->added);
g_hash_table_remove_all (self->removed);
GST_OBJECT_UNLOCK (self);
gst_structure_take_value (s, "objects-created-list", &added);
gst_structure_take_value (s, "objects-removed-list", &removed);
return s;
}
static void
gst_leaks_tracer_activity_log_checkpoint (GstLeaksTracer * self)
{
GST_OBJECT_LOCK (self);
GST_TRACE_OBJECT (self, "listing objects created since last checkpoint");
process_checkpoint (tr_added, NULL, self->added, NULL);
GST_TRACE_OBJECT (self, "listing objects removed since last checkpoint");
process_checkpoint (tr_removed, NULL, self->removed, NULL);
g_hash_table_remove_all (self->added);
g_hash_table_remove_all (self->removed);
GST_OBJECT_UNLOCK (self);
}
static void
gst_leaks_tracer_activity_stop_tracking (GstLeaksTracer * self)
{
GST_OBJECT_LOCK (self);
g_clear_pointer (&self->added, g_hash_table_destroy);
g_clear_pointer (&self->removed, g_hash_table_destroy);
GST_OBJECT_UNLOCK (self);
}
static void
gst_leaks_tracer_class_init (GstLeaksTracerClass * klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->constructed = gst_leaks_tracer_constructed;
gobject_class->finalize = gst_leaks_tracer_finalize;
tr_alive = gst_tracer_record_new ("object-alive.class",
RECORD_FIELD_TYPE_NAME, RECORD_FIELD_ADDRESS, RECORD_FIELD_DESC,
RECORD_FIELD_REF_COUNT, RECORD_FIELD_TRACE, NULL);
GST_OBJECT_FLAG_SET (tr_alive, GST_OBJECT_FLAG_MAY_BE_LEAKED);
tr_refings = gst_tracer_record_new ("object-refings.class",
RECORD_FIELD_TYPE_TS, RECORD_FIELD_TYPE_NAME, RECORD_FIELD_ADDRESS,
RECORD_FIELD_DESC, RECORD_FIELD_REF_COUNT, RECORD_FIELD_TRACE, NULL);
GST_OBJECT_FLAG_SET (tr_alive, GST_OBJECT_FLAG_MAY_BE_LEAKED);
tr_added = gst_tracer_record_new ("object-added.class",
RECORD_FIELD_TYPE_NAME, RECORD_FIELD_ADDRESS, NULL);
GST_OBJECT_FLAG_SET (tr_added, GST_OBJECT_FLAG_MAY_BE_LEAKED);
tr_removed = gst_tracer_record_new ("object-removed.class",
RECORD_FIELD_TYPE_NAME, RECORD_FIELD_ADDRESS, NULL);
GST_OBJECT_FLAG_SET (tr_removed, GST_OBJECT_FLAG_MAY_BE_LEAKED);
/**
* GstLeaksTracer::get-live-objects:
* @leakstracer: the leaks tracer object to emit this signal on
*
* Returns a #GstStructure containing a #GValue of type #GST_TYPE_LIST which
* is a list of #GstStructure objects containing information about the
* objects that are still alive, which is useful for detecting leaks. Each
* #GstStructure object has the following fields:
*
* `object`: containing the leaked object itself
* `ref-count`: the current reference count of the object
* `trace`: the allocation stack trace for the object, only available if the
* `stack-traces-flags` param is set to `full`
* `ref-infos`: a #GValue of type #GST_TYPE_LIST which is a list of
* #GstStructure objects containing information about the
* ref/unref history of the object; only available if the
* `check-refs` param is set to `true`
*
* Each `ref-infos` #GstStructure has the following fields:
*
* `ts`: the timestamp for the ref/unref
* `desc`: either "reffed" or "unreffed"
* `ref-count`: the reference count after the ref/unref
* `trace`: the stack trace for the ref/unref
*
* **Notes on usage**: This action signal is supposed to be called at the
* end of an application before it exits, or at the end of an execution run
* when all streaming has stopped and all pipelines have been freed. It is
* assumed that at this point any GStreamer object that is still alive is
* leaked, and there are no legitimate owners any more. As such, ownership
* of the leaked objects is transferred to you then, assuming no other code
* still retrains references to them.
*
* If that's not the case, and there is code somewhere still holding
* a reference, then the application behaviour is undefined after this
* function is called, since we will have stolen some other code's valid
* reference and when the returned #GstStructure is freed that code will be
* holding a reference to an invalid object, which will most likely crash
* sooner or later.
*
* If you don't want to just check for leaks at the end of a program, the
* activity checkpoint action signals might be a better fit for your use
* case.
*
* Returns: (transfer full): a newly-allocated #GstStructure
*
* Since: 1.18
*/
gst_leaks_tracer_signals[SIGNAL_GET_LIVE_OBJECTS] =
g_signal_new ("get-live-objects", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstLeaksTracerClass,
get_live_objects), NULL, NULL, NULL, GST_TYPE_STRUCTURE, 0,
G_TYPE_NONE);
/**
* GstLeaksTracer::log-live-objects:
* @leakstracer: the leaks tracer object to emit this signal on
*
* Logs all objects that are still alive to the debug log in the same format
* as the logging during gst_deinit().
*
* Since: 1.18
*/
gst_leaks_tracer_signals[SIGNAL_LOG_LIVE_OBJECTS] =
g_signal_new ("log-live-objects", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstLeaksTracerClass,
log_live_objects), NULL, NULL, NULL, G_TYPE_NONE, 0, G_TYPE_NONE);
/**
* GstLeaksTracer:::activity-start-tracking
* @leakstracer: the leaks tracer object to emit this signal on
*
* Start storing information about all objects that are being created or
* removed. Call `stop-tracking` to stop.
*
* NOTE: You do not need to call this to use the *-live-objects action
* signals listed above.
*
* Since: 1.18
*/
gst_leaks_tracer_signals[SIGNAL_ACTIVITY_START_TRACKING] =
g_signal_new ("activity-start-tracking", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstLeaksTracerClass,
activity_start_tracking), NULL, NULL, NULL, G_TYPE_NONE, 0,
G_TYPE_NONE);
/**
* GstLeaksTracer:::activity-get-checkpoint
* @leakstracer: the leaks tracer object to emit this signal on
*
* You must call this after calling `activity-start-tracking` and you should
* call `activity-stop-tracking` when you are done tracking.
*
* Returns a #GstStructure with two fields: `"objects-created-list"` and
* `"objects-removed-list"`, each of which is a #GValue of type #GST_TYPE_LIST
* containing all objects that were created/removed since the last
* checkpoint, or since tracking started if this is the first checkpoint.
*
* The list elements are in order of creation/removal. Each list element is
* a #GValue containing a #GstStructure with the following fields:
*
* `type-name`: a string representing the type of the object
* `address`: a string representing the address of the object; the object
* itself cannot be returned since we don't own it and it may be
* freed at any moment, or it may already have been freed
*
* Returns: (transfer full): a newly-allocated #GstStructure
*
* Since: 1.18
*/
gst_leaks_tracer_signals[SIGNAL_ACTIVITY_GET_CHECKPOINT] =
g_signal_new ("activity-get-checkpoint", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstLeaksTracerClass,
activity_get_checkpoint), NULL, NULL, NULL, GST_TYPE_STRUCTURE, 0,
G_TYPE_NONE);
/**
* GstLeaksTracer:::activity-log-checkpoint
* @leakstracer: the leaks tracer object to emit this signal on
*
* You must call this after calling `activity-start-tracking` and you should
* call `activity-stop-tracking` when you are done tracking.
*
* List all objects that were created or removed since the last checkpoint,
* or since tracking started if this is the first checkpoint.
*
* This action signal is equivalent to `activity-get-checkpoint` except that
* the checkpoint data will be printed to the debug log under `GST_TRACER:7`.
*
* Since: 1.18
*/
gst_leaks_tracer_signals[SIGNAL_ACTIVITY_LOG_CHECKPOINT] =
g_signal_new ("activity-log-checkpoint", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstLeaksTracerClass,
activity_log_checkpoint), NULL, NULL, NULL, G_TYPE_NONE, 0,
G_TYPE_NONE);
/**
* GstLeaksTracer:::activity-stop-tracking
* @leakstracer: the leaks tracer object to emit this signal on
*
* Stop tracking all objects that are being created or removed, undoes the
* effects of the `start-tracking` signal.
*
* Since: 1.18
*/
gst_leaks_tracer_signals[SIGNAL_ACTIVITY_STOP_TRACKING] =
g_signal_new ("activity-stop-tracking", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstLeaksTracerClass,
activity_stop_tracking), NULL, NULL, NULL, G_TYPE_NONE, 0,
G_TYPE_NONE);
klass->get_live_objects = gst_leaks_tracer_get_live_objects;
klass->log_live_objects = gst_leaks_tracer_log_live_objects;
klass->activity_start_tracking = gst_leaks_tracer_activity_start_tracking;
klass->activity_get_checkpoint = gst_leaks_tracer_activity_get_checkpoint;
klass->activity_log_checkpoint = gst_leaks_tracer_activity_log_checkpoint;
klass->activity_stop_tracking = gst_leaks_tracer_activity_stop_tracking;
}