[PATCH 1/2] evr/sample: Avoid a race condition when releasing a tracked sample.

[Nikolay Sivov]

Same as b1807751219e256867eaac5cc4d8b97a5482978f.

Signed-off-by: Nikolay Sivov 
---
 dlls/evr/sample.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/dlls/evr/sample.c b/dlls/evr/sample.c
index 1d29b6cdc2c..738f803fe66 100644
--- a/dlls/evr/sample.c
+++ b/dlls/evr/sample.c
@@ -920,19 +920,21 @@ static ULONG WINAPI video_sample_AddRef(IMFSample *iface)
 static ULONG WINAPI video_sample_Release(IMFSample *iface)
 {
     struct video_sample *sample = impl_from_IMFSample(iface);
-    ULONG refcount;
+    ULONG refcount = InterlockedDecrement(&sample->refcount);
+    IMFAsyncResult *tracked_result = NULL;

IMFSample_LockStore(sample->sample);
-    if (sample->tracked_result && sample->tracked_refcount == (sample->refcount - 1))
+    if (sample->tracked_result && sample->tracked_refcount == refcount)
     {
-        video_sample_tracking_thread_invoke(sample->tracked_result);
-        IMFAsyncResult_Release(sample->tracked_result);
+        tracked_result = sample->tracked_result;
+        video_sample_tracking_thread_invoke(tracked_result);
         sample->tracked_result = NULL;
         sample->tracked_refcount = 0;
     }
     IMFSample_UnlockStore(sample->sample);

-    refcount = InterlockedDecrement(&sample->refcount);
+    if (tracked_result)
+        IMFAsyncResult_Release(tracked_result);

TRACE("%p, refcount %lu.\n", iface, refcount);

[PATCH 2/2] evr/sample: Use explicit critical section for release handling.

[Nikolay Sivov]

Signed-off-by: Nikolay Sivov 
---

Locking methods were used here before critical section was introduced,
no reason to use them now.

dlls/evr/sample.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/dlls/evr/sample.c b/dlls/evr/sample.c
index 738f803fe66..3521e6c4d51 100644
--- a/dlls/evr/sample.c
+++ b/dlls/evr/sample.c
@@ -923,7 +923,7 @@ static ULONG WINAPI video_sample_Release(IMFSample *iface)
     ULONG refcount = InterlockedDecrement(&sample->refcount);
     IMFAsyncResult *tracked_result = NULL;

-    IMFSample_LockStore(sample->sample);
+    EnterCriticalSection(&sample->cs);
     if (sample->tracked_result && sample->tracked_refcount == refcount)
     {
         tracked_result = sample->tracked_result;
@@ -931,7 +931,7 @@ static ULONG WINAPI video_sample_Release(IMFSample *iface)
         sample->tracked_result = NULL;
         sample->tracked_refcount = 0;
     }
-    IMFSample_UnlockStore(sample->sample);
+    LeaveCriticalSection(&sample->cs);

if (tracked_result)
         IMFAsyncResult_Release(tracked_result);