[PATCH 1/1] winegstreamer: Protect wg_transform drain and flush by mutex.

[Charlotte Pabst]

From: Charlotte Pabst <[e-mail]>

When flushing and draining at the same time from different threads without
synchronization, one of them may fail and in the worst case, both fail,
and the pipeline gets permanently stuck in EOS state.
---
 dlls/winegstreamer/wg_transform.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/dlls/winegstreamer/wg_transform.c b/dlls/winegstreamer/wg_transform.c
index f8bf4474756..32fc6d72d16 100644
--- a/dlls/winegstreamer/wg_transform.c
+++ b/dlls/winegstreamer/wg_transform.c
@@ -95,6 +95,7 @@ struct wg_transform
     GstCaps *output_caps;
     GstCaps *input_caps;
 
+    pthread_mutex_t mutex;
     bool draining;
     INT64 ts_offset;
 };
@@ -485,6 +486,7 @@ NTSTATUS wg_transform_destroy(void *args)
     gst_caps_unref(transform->output_caps);
     gst_caps_unref(transform->input_caps);
     gst_atomic_queue_unref(transform->output_queue);
+    pthread_mutex_destroy(&transform->mutex);
     free(transform);
 
     return STATUS_SUCCESS;
@@ -756,6 +758,8 @@ NTSTATUS wg_transform_create(void *args)
             || !push_event(transform->my_src, event))
         goto out;
 
+    pthread_mutex_init(&transform->mutex, NULL);
+
     GST_INFO("Created winegstreamer transform %p.", transform);
     params->transform = (wg_transform_t)(ULONG_PTR)transform;
     return STATUS_SUCCESS;
@@ -1170,6 +1174,13 @@ error:
     return STATUS_UNSUCCESSFUL;
 }
 
+static NTSTATUS drain_transform(struct wg_transform *transform)
+{
+    GST_LOG("transform %p, draining %d buffers", transform, gst_atomic_queue_length(transform->input_queue));
+    transform->draining = true;
+    return complete_drain(transform);
+}
+
 static bool get_transform_output(struct wg_transform *transform, struct wg_sample *sample)
 {
     GstFlowReturn ret;
@@ -1312,12 +1323,13 @@ NTSTATUS wg_transform_get_status(void *args)
 NTSTATUS wg_transform_drain(void *args)
 {
     struct wg_transform *transform = get_transform(*(wg_transform_t *)args);
+    NTSTATUS status;
 
-    GST_LOG("transform %p, draining %d buffers", transform, gst_atomic_queue_length(transform->input_queue));
-
-    transform->draining = true;
+    pthread_mutex_lock(&transform->mutex);
+    status = drain_transform(transform);
+    pthread_mutex_unlock(&transform->mutex);
 
-    return complete_drain(transform);
+    return status;
 }
 
 NTSTATUS wg_transform_flush(void *args)
@@ -1328,6 +1340,7 @@ NTSTATUS wg_transform_flush(void *args)
     GstEvent *event;
     NTSTATUS status;
 
+    pthread_mutex_lock(&transform->mutex);
     GST_LOG("transform %p", transform);
 
     /* this ensures no messages are travelling through the pipeline whilst we flush */
@@ -1343,16 +1356,19 @@ NTSTATUS wg_transform_flush(void *args)
     event = gst_event_new_flush_stop(true);
     gst_pad_push_event(transform->my_src, event);
 
-    if ((status = wg_transform_drain(args)))
-        return status;
+    if ((status = drain_transform(transform)))
+        goto out;
 
     while ((sample = gst_atomic_queue_pop(transform->output_queue)))
         gst_sample_unref(sample);
     if ((sample = transform->output_sample))
         gst_sample_unref(sample);
     transform->output_sample = NULL;
+    status = STATUS_SUCCESS;
 
-    return STATUS_SUCCESS;
+out:
+    pthread_mutex_unlock(&transform->mutex);
+    return status;
 }
 
 NTSTATUS wg_transform_notify_qos(void *args)
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/9937