Modified: trunk/Source/WebCore/ChangeLog (225634 => 225635)
--- trunk/Source/WebCore/ChangeLog 2017-12-07 19:06:17 UTC (rev 225634)
+++ trunk/Source/WebCore/ChangeLog 2017-12-07 19:25:35 UTC (rev 225635)
@@ -1,3 +1,26 @@
+2017-12-07 Jer Noble <[email protected]>
+
+ [EME] Possible deadlock when aborting a SourceBufferPrivateAVFObjC append operation
+ https://bugs.webkit.org/show_bug.cgi?id=180486
+
+ Reviewed by Eric Carlson.
+
+ It's possible that an abort() operation which is blocked on the ongoing appendBuffer()
+ operation completing will deadlock forever, with either the willProvideContentKeyRequest
+ or didProvideContentKeyRequest callbacks blocking waiting to be run on the main thread
+ (which is itself blocked waiting for the append operation to complete).
+
+ To break this deadlock, add a new abortSemaphore which is signaled in the abort() method
+ and have the willProvide... and didProvide... methods block both on their own semaphores
+ as well as the abortSemaphore, allowing them to break out even if their main thread calls
+ never get a chance to execute.
+
+ * platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm:
+ (-[WebAVStreamDataParserListener streamDataParserWillProvideContentKeyRequestInitializationData:forTrackID:]):
+ (-[WebAVStreamDataParserListener streamDataParser:didProvideContentKeyRequestInitializationData:forTrackID:]):
+ (WebCore::SourceBufferPrivateAVFObjC::SourceBufferPrivateAVFObjC):
+ (WebCore::SourceBufferPrivateAVFObjC::abort):
+
2017-12-07 Eric Carlson <[email protected]>
Simplify log channel configuration UI
Modified: trunk/Source/WebCore/platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm (225634 => 225635)
--- trunk/Source/WebCore/platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm 2017-12-07 19:06:17 UTC (rev 225634)
+++ trunk/Source/WebCore/platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm 2017-12-07 19:25:35 UTC (rev 225635)
@@ -108,9 +108,11 @@
@interface WebAVStreamDataParserListener : NSObject<AVStreamDataParserOutputHandling> {
WeakPtr<WebCore::SourceBufferPrivateAVFObjC> _parent;
+ OSObjectPtr<dispatch_semaphore_t> _abortSemaphore;
AVStreamDataParser* _parser;
}
@property (assign) WeakPtr<WebCore::SourceBufferPrivateAVFObjC> parent;
+@property (assign) OSObjectPtr<dispatch_semaphore_t> abortSemaphore;
- (id)initWithParser:(AVStreamDataParser*)parser parent:(WeakPtr<WebCore::SourceBufferPrivateAVFObjC>)parent;
@end
@@ -129,6 +131,7 @@
}
@synthesize parent=_parent;
+@synthesize abortSemaphore=_abortSemaphore;
- (void)dealloc
{
@@ -203,10 +206,22 @@
// We must call synchronously to the main thread, as the AVStreamSession must be associated
// with the streamDataParser before the delegate method returns.
- dispatch_sync(dispatch_get_main_queue(), [parent = _parent, trackID]() {
+ OSObjectPtr<dispatch_semaphore_t> respondedSemaphore = adoptOSObject(dispatch_semaphore_create(0));
+ callOnMainThread([parent = _parent, trackID, respondedSemaphore]() {
if (parent)
parent->willProvideContentKeyRequestInitializationDataForTrackID(trackID);
+ dispatch_semaphore_signal(respondedSemaphore.get());
});
+
+ while (true) {
+ if (!dispatch_semaphore_wait(respondedSemaphore.get(), dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_MSEC * 100)))
+ return;
+
+ if (!dispatch_semaphore_wait(_abortSemaphore.get(), dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_MSEC * 100))) {
+ dispatch_semaphore_signal(_abortSemaphore.get());
+ return;
+ }
+ }
}
- (void)streamDataParser:(AVStreamDataParser *)streamDataParser didProvideContentKeyRequestInitializationData:(NSData *)initData forTrackID:(CMPersistentTrackID)trackID
@@ -218,7 +233,16 @@
if (parent)
parent->didProvideContentKeyRequestInitializationDataForTrackID(protectedInitData.get(), trackID, hasSessionSemaphore);
});
- dispatch_semaphore_wait(hasSessionSemaphore.get(), DISPATCH_TIME_FOREVER);
+
+ while (true) {
+ if (!dispatch_semaphore_wait(hasSessionSemaphore.get(), dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_MSEC * 100)))
+ return;
+
+ if (!dispatch_semaphore_wait(_abortSemaphore.get(), dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_MSEC * 100))) {
+ dispatch_semaphore_signal(_abortSemaphore.get());
+ return;
+ }
+ }
}
@end
@@ -487,6 +511,7 @@
, m_mediaSource(parent)
{
CMNotificationCenterAddListener(CMNotificationCenterGetDefaultLocalCenter(), this, bufferWasConsumedCallback, kCMSampleBufferConsumerNotification_BufferConsumed, nullptr, 0);
+ m_delegate.get().abortSemaphore = adoptOSObject(dispatch_semaphore_create(0));
}
SourceBufferPrivateAVFObjC::~SourceBufferPrivateAVFObjC()
@@ -713,9 +738,11 @@
// semaphore, the m_isAppendingGroup wait operation will deadlock.
if (m_hasSessionSemaphore)
dispatch_semaphore_signal(m_hasSessionSemaphore.get());
+ dispatch_semaphore_signal(m_delegate.get().abortSemaphore.get());
dispatch_group_wait(m_isAppendingGroup.get(), DISPATCH_TIME_FOREVER);
m_appendWeakFactory.revokeAll();
m_delegate.get().parent = m_appendWeakFactory.createWeakPtr(*this);
+ m_delegate.get().abortSemaphore = adoptOSObject(dispatch_semaphore_create(0));
}
void SourceBufferPrivateAVFObjC::resetParserState()
