[vlc-commits] vout: ios: fix gpu_ReturnNotPermittedKillClient crashes

Thomas Guillem git at videolan.org
Wed Mar 7 15:47:37 CET 2018


vlc/vlc-3.0 | branch: master | Thomas Guillem <thomas at gllm.fr> | Wed Mar  7 09:11:38 2018 +0100| [d821deaa75b3d2cfb9ca948016826b26c4026c51] | committer: Thomas Guillem

vout: ios: fix gpu_ReturnNotPermittedKillClient crashes

cf. https://developer.apple.com/library/content/qa/qa1766/_index.html

No OpenGLES call should be made once the application entered background.

To fix this issue, this commit disable any rendering (_appActive = NO;) and
flush all OpenGLES commands from the applicationDidEnterBackground
notification.

This commits adds a lock and a condition in order to let the main thread know
when the VLC vout thread unlocked the EAGLContext (because we don't want to
flush this context while it's being used by the vout thread).

(cherry picked from commit 1399ebae2e123cf3ba112946014b59ef34d639dd)
Signed-off-by: Thomas Guillem <thomas at gllm.fr>

> http://git.videolan.org/gitweb.cgi/vlc/vlc-3.0.git/?a=commit;h=d821deaa75b3d2cfb9ca948016826b26c4026c51
---

 modules/video_output/ios.m | 108 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 89 insertions(+), 19 deletions(-)

diff --git a/modules/video_output/ios.m b/modules/video_output/ios.m
index 776624ec44..1ea2ee45aa 100644
--- a/modules/video_output/ios.m
+++ b/modules/video_output/ios.m
@@ -91,9 +91,12 @@ vlc_module_end ()
     CAEAGLLayer *_layer;
 
     vlc_mutex_t _mutex;
+    vlc_cond_t  _gl_attached_wait;
+    BOOL        _gl_attached;
 
     BOOL _bufferNeedReset;
     BOOL _appActive;
+    BOOL _eaglEnabled;
     BOOL _placeInvalidated;
 
     UIView *_viewContainer;
@@ -109,7 +112,7 @@ vlc_module_end ()
 }
 
 - (id)initWithFrameAndVd:(CGRect)frame withVd:(vout_display_t*)vd;
-- (void)cleanAndRelease;
+- (void)cleanAndRelease:(BOOL)flushed;
 - (BOOL)makeCurrentWithGL:(EAGLContext **)previousEaglContext withGL:(vlc_gl_t *)gl;
 - (void)releaseCurrent:(EAGLContext *)previousEaglContext;
 - (void)presentRenderbuffer;
@@ -233,6 +236,7 @@ static void Close (vlc_object_t *this)
     vout_display_sys_t *sys = vd->sys;
 
     @autoreleasepool {
+        BOOL flushed = NO;
         if (sys->gl != NULL) {
             struct gl_sys *glsys = sys->gl->sys;
             msg_Dbg(this, "deleting display");
@@ -242,12 +246,15 @@ static void Close (vlc_object_t *this)
                 int ret = vlc_gl_MakeCurrent(sys->gl);
                 vout_display_opengl_Delete(glsys->vgl);
                 if (ret == VLC_SUCCESS)
+                {
                     vlc_gl_ReleaseCurrent(sys->gl);
+                    flushed = YES;
+                }
             }
             vlc_object_release(sys->gl);
         }
 
-        [sys->glESView cleanAndRelease];
+        [sys->glESView cleanAndRelease:flushed];
     }
     var_Destroy(vd->obj.parent, "ios-eaglcontext");
 }
@@ -391,11 +398,14 @@ static void GLESSwap(vlc_gl_t *gl)
     if (!self)
         return nil;
 
+    _eaglEnabled = YES;
     _bufferNeedReset = YES;
     _voutDisplay = vd;
     _cfg = *_voutDisplay->cfg;
 
     vlc_mutex_init(&_mutex);
+    vlc_cond_init(&_gl_attached_wait);
+    _gl_attached = YES;
 
     /* the following creates a new OpenGL ES context with the API version we
      * need if there is already an active context created by another OpenGL
@@ -411,6 +421,7 @@ static void GLESSwap(vlc_gl_t *gl)
         if (_eaglContext)
             [_eaglContext release];
         vlc_mutex_destroy(&_mutex);
+        vlc_cond_destroy(&_gl_attached_wait);
         [super dealloc];
         return nil;
     }
@@ -428,6 +439,7 @@ static void GLESSwap(vlc_gl_t *gl)
     if (![self fetchViewContainer])
     {
         vlc_mutex_destroy(&_mutex);
+        vlc_cond_destroy(&_gl_attached_wait);
         [_eaglContext release];
         [super dealloc];
         return nil;
@@ -442,6 +454,15 @@ static void GLESSwap(vlc_gl_t *gl)
                                              selector:@selector(applicationStateChanged:)
                                                  name:UIApplicationDidBecomeActiveNotification
                                                object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(applicationStateChanged:)
+                                                 name:UIApplicationDidEnterBackgroundNotification
+                                               object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(applicationStateChanged:)
+                                                 name:UIApplicationWillEnterForegroundNotification
+                                               object:nil];
+
     return self;
 }
 
@@ -494,20 +515,8 @@ static void GLESSwap(vlc_gl_t *gl)
     }
 }
 
-- (void)cleanAndRelease
+- (void)cleanAndReleaseFromMainThread
 {
-    if (![NSThread isMainThread])
-    {
-        vlc_mutex_lock(&_mutex);
-        _voutDisplay = nil;
-        vlc_mutex_unlock(&_mutex);
-
-        [self performSelectorOnMainThread:@selector(cleanAndRelease)
-                               withObject:nil
-                            waitUntilDone:NO];
-        return;
-    }
-
     [[NSNotificationCenter defaultCenter] removeObserver:self];
 
     [_tapRecognizer.view removeGestureRecognizer:_tapRecognizer];
@@ -516,13 +525,29 @@ static void GLESSwap(vlc_gl_t *gl)
     [self removeFromSuperview];
     [_viewContainer release];
 
+    assert(!_gl_attached);
     [_eaglContext release];
     [self release];
 }
 
+- (void)cleanAndRelease:(BOOL)flushed
+{
+    vlc_mutex_lock(&_mutex);
+    if (_eaglEnabled && !flushed)
+        [self flushEAGLLocked];
+    _voutDisplay = nil;
+    _eaglEnabled = NO;
+    vlc_mutex_unlock(&_mutex);
+
+    [self performSelectorOnMainThread:@selector(cleanAndReleaseFromMainThread)
+                           withObject:nil
+                        waitUntilDone:NO];
+}
+
 - (void)dealloc
 {
     vlc_mutex_destroy(&_mutex);
+    vlc_cond_destroy(&_gl_attached_wait);
     [super dealloc];
 }
 
@@ -575,12 +600,14 @@ static void GLESSwap(vlc_gl_t *gl)
 - (BOOL)makeCurrentWithGL:(EAGLContext **)previousEaglContext withGL:(vlc_gl_t *)gl
 {
     vlc_mutex_lock(&_mutex);
+    assert(!_gl_attached);
 
     if (unlikely(!_appActive))
     {
         vlc_mutex_unlock(&_mutex);
         return NO;
     }
+    assert(_eaglEnabled);
 
     *previousEaglContext = [EAGLContext currentContext];
 
@@ -609,11 +636,14 @@ static void GLESSwap(vlc_gl_t *gl)
         }
     }
 
+    if (success)
+        _gl_attached = YES;
+
     vlc_mutex_unlock(&_mutex);
 
     if (resetBuffers && ![self doResetBuffers:gl])
     {
-        [EAGLContext setCurrentContext:*previousEaglContext];
+        [self releaseCurrent:*previousEaglContext];
         return NO;
     }
     return success;
@@ -622,6 +652,12 @@ static void GLESSwap(vlc_gl_t *gl)
 - (void)releaseCurrent:(EAGLContext *)previousEaglContext
 {
     [EAGLContext setCurrentContext:previousEaglContext];
+
+    vlc_mutex_lock(&_mutex);
+    assert(_gl_attached);
+    _gl_attached = NO;
+    vlc_mutex_unlock(&_mutex);
+    vlc_cond_signal(&_gl_attached_wait);
 }
 
 - (void)presentRenderbuffer
@@ -718,16 +754,50 @@ static void GLESSwap(vlc_gl_t *gl)
                         waitUntilDone:NO];
 }
 
+- (void)flushEAGLLocked
+{
+    assert(_eaglEnabled);
+
+    /* Ensure that all previously submitted commands are drained from the
+     * command buffer and are executed by OpenGL ES before moving to the
+     * background.*/
+    EAGLContext *previousEaglContext = [EAGLContext currentContext];
+    if ([EAGLContext setCurrentContext:_eaglContext])
+    {
+        glFinish();
+        glFlush();
+    }
+    [EAGLContext setCurrentContext:previousEaglContext];
+}
+
 - (void)applicationStateChanged:(NSNotification *)notification
 {
     vlc_mutex_lock(&_mutex);
 
-    if ([[notification name] isEqualToString:UIApplicationWillResignActiveNotification]
-        || [[notification name] isEqualToString:UIApplicationDidEnterBackgroundNotification]
-        || [[notification name] isEqualToString:UIApplicationWillTerminateNotification])
+    if ([[notification name] isEqualToString:UIApplicationWillResignActiveNotification])
+        _appActive = NO;
+    else if ([[notification name] isEqualToString:UIApplicationDidEnterBackgroundNotification])
+    {
         _appActive = NO;
+
+        if (_eaglEnabled)
+        {
+            /* Wait for the vout to unlock the eagl context before releasing
+             * it. */
+            while (_gl_attached)
+                vlc_cond_wait(&_gl_attached_wait, &_mutex);
+
+            [self flushEAGLLocked];
+            _eaglEnabled = NO;
+        }
+    }
+    else if ([[notification name] isEqualToString:UIApplicationWillEnterForegroundNotification])
+        _eaglEnabled = YES;
     else
+    {
+        assert([[notification name] isEqualToString:UIApplicationDidBecomeActiveNotification]);
         _appActive = YES;
+    }
 
     vlc_mutex_unlock(&_mutex);
 }



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