[libcamera-devel,v2,26/27] gst: libcamerasrc: Prevent src task deadlock on exhausted buffer pool
diff mbox series

Message ID 20200227200407.490616-27-nicolas.dufresne@collabora.com
State Accepted
Headers show
Series
  • GStreamer Element for libcamera
Related show

Commit Message

Nicolas Dufresne Feb. 27, 2020, 8:04 p.m. UTC 
From: Jakub Adam <jakub.adam@collabora.com>

Allow GstLibcameraPool to notify the source when a new buffer has become
available in a previously exhausted buffer pool. This can be used to
resume a src task that got paused because it couldn't acquire a buffer.

Without this change the src task will never resume from pause once the
pool gets exhausted.

To trigger the deadlock (it doesn't happen every time), run:

  gst-launch-1.0 libcamerasrc ! queue ! glimagesink

Signed-off-by: Jakub Adam <jakub.adam@collabora.com>
---
 src/gstreamer/gstlibcamerapool.cpp | 16 ++++++++++++++++
 src/gstreamer/gstlibcamerapool.h   |  6 ++++++
 src/gstreamer/gstlibcamerasrc.cpp  | 14 ++++++++++++--
 3 files changed, 34 insertions(+), 2 deletions(-)

Comments

Laurent Pinchart Feb. 29, 2020, 3:11 p.m. UTC | #1 
Hi Nicolas and Jakub,

Thank you for the patch.

On Thu, Feb 27, 2020 at 03:04:06PM -0500, Nicolas Dufresne wrote:
> From: Jakub Adam <jakub.adam@collabora.com>
> 
> Allow GstLibcameraPool to notify the source when a new buffer has become
> available in a previously exhausted buffer pool. This can be used to
> resume a src task that got paused because it couldn't acquire a buffer.
> 
> Without this change the src task will never resume from pause once the
> pool gets exhausted.
> 
> To trigger the deadlock (it doesn't happen every time), run:
> 
>   gst-launch-1.0 libcamerasrc ! queue ! glimagesink
> 
> Signed-off-by: Jakub Adam <jakub.adam@collabora.com>
> ---
>  src/gstreamer/gstlibcamerapool.cpp | 16 ++++++++++++++++
>  src/gstreamer/gstlibcamerapool.h   |  6 ++++++
>  src/gstreamer/gstlibcamerasrc.cpp  | 14 ++++++++++++--
>  3 files changed, 34 insertions(+), 2 deletions(-)
> 
> diff --git a/src/gstreamer/gstlibcamerapool.cpp b/src/gstreamer/gstlibcamerapool.cpp
> index f85c3aa..5aa0eeb 100644
> --- a/src/gstreamer/gstlibcamerapool.cpp
> +++ b/src/gstreamer/gstlibcamerapool.cpp
> @@ -18,6 +18,8 @@ struct _GstLibcameraPool {
>  
>  	GstAtomicQueue *queue;
>  	GstLibcameraAllocator *allocator;
> +	GstLibcameraBufferNotify buffer_notify;
> +	gpointer buffer_notify_data;
>  	Stream *stream;
>  };
>  
> @@ -54,7 +56,12 @@ static void
>  gst_libcamera_pool_release_buffer(GstBufferPool *pool, GstBuffer *buffer)
>  {
>  	GstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);
> +	bool do_notify = gst_atomic_queue_length(self->queue) == 0;
> +
>  	gst_atomic_queue_push(self->queue, buffer);
> +
> +	if (do_notify && self->buffer_notify)
> +		self->buffer_notify(self->buffer_notify_data);
>  }
>  
>  static void
> @@ -108,6 +115,15 @@ gst_libcamera_pool_new(GstLibcameraAllocator *allocator, Stream *stream)
>  	return pool;
>  }
>  
> +void
> +gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
> +				     GstLibcameraBufferNotify notify,
> +				     gpointer data)
> +{
> +	self->buffer_notify = notify;
> +	self->buffer_notify_data = data;
> +}
> +
>  Stream *
>  gst_libcamera_pool_get_stream(GstLibcameraPool *self)
>  {
> diff --git a/src/gstreamer/gstlibcamerapool.h b/src/gstreamer/gstlibcamerapool.h
> index 6fd2913..545be01 100644
> --- a/src/gstreamer/gstlibcamerapool.h
> +++ b/src/gstreamer/gstlibcamerapool.h
> @@ -20,9 +20,15 @@
>  #define GST_TYPE_LIBCAMERA_POOL gst_libcamera_pool_get_type()
>  G_DECLARE_FINAL_TYPE(GstLibcameraPool, gst_libcamera_pool, GST_LIBCAMERA, POOL, GstBufferPool)
>  
> +typedef void (*GstLibcameraBufferNotify)(gpointer data);
> +
>  GstLibcameraPool *gst_libcamera_pool_new(GstLibcameraAllocator *allocator,
>  					 libcamera::Stream *stream);
>  
> +void gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
> +					  GstLibcameraBufferNotify notify,
> +					  gpointer data);
> +
>  libcamera::Stream *gst_libcamera_pool_get_stream(GstLibcameraPool *self);
>  
>  libcamera::Stream *gst_libcamera_buffer_get_stream(GstBuffer *buffer);
> diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> index fe60584..ecbfe37 100644
> --- a/src/gstreamer/gstlibcamerasrc.cpp
> +++ b/src/gstreamer/gstlibcamerasrc.cpp
> @@ -434,6 +434,10 @@ gst_libcamera_src_task_enter(GstTask *task, GThread *thread, gpointer user_data)
>  		const StreamConfiguration &stream_cfg = state->config->at(i);
>  		GstLibcameraPool *pool = gst_libcamera_pool_new(self->allocator,
>  								stream_cfg.stream());
> +		gst_libcamera_pool_set_buffer_notify(pool,
> +						     (GstLibcameraBufferNotify)gst_libcamera_resume_task,
> +						     task);
> +
>  		gst_libcamera_pad_set_pool(srcpad, pool);
>  		gst_flow_combiner_add_pad(self->flow_combiner, srcpad);
>  	}
> @@ -468,8 +472,14 @@ gst_libcamera_src_task_leave(GstTask *task, GThread *thread, gpointer user_data)
>  
>  	state->cam->stop();
>  
> -	for (GstPad *srcpad : state->srcpads)
> -		gst_libcamera_pad_set_pool(srcpad, NULL);
> +	for (GstPad *srcpad : state->srcpads) {
> +		auto *pool = gst_libcamera_pad_get_pool(srcpad);
> +
> +		if (pool) {
> +			gst_libcamera_pool_set_buffer_notify(pool, NULL, NULL);
> +			gst_libcamera_pad_set_pool(srcpad, NULL);

s/NULL/nullptr/

Up to you, but you could also use a Signal. This would however require
C++ objects, so some refactoring would be needed, and it may not be
worth it, but adding ad-hoc callback registration is a step on the
slippery slope to towards spaghetti code :-)

> +		}
> +	}
>  
>  	g_clear_object(&self->allocator);
>  	g_clear_pointer(&self->flow_combiner,
Nicolas Dufresne Feb. 29, 2020, 3:35 p.m. UTC | #2 
Le samedi 29 février 2020 à 17:11 +0200, Laurent Pinchart a écrit :
> Hi Nicolas and Jakub,
> 
> Thank you for the patch.
> 
> On Thu, Feb 27, 2020 at 03:04:06PM -0500, Nicolas Dufresne wrote:
> > From: Jakub Adam <jakub.adam@collabora.com>
> > 
> > Allow GstLibcameraPool to notify the source when a new buffer has become
> > available in a previously exhausted buffer pool. This can be used to
> > resume a src task that got paused because it couldn't acquire a buffer.
> > 
> > Without this change the src task will never resume from pause once the
> > pool gets exhausted.
> > 
> > To trigger the deadlock (it doesn't happen every time), run:
> > 
> >   gst-launch-1.0 libcamerasrc ! queue ! glimagesink
> > 
> > Signed-off-by: Jakub Adam <jakub.adam@collabora.com>
> > ---
> >  src/gstreamer/gstlibcamerapool.cpp | 16 ++++++++++++++++
> >  src/gstreamer/gstlibcamerapool.h   |  6 ++++++
> >  src/gstreamer/gstlibcamerasrc.cpp  | 14 ++++++++++++--
> >  3 files changed, 34 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/gstreamer/gstlibcamerapool.cpp b/src/gstreamer/gstlibcamerapool.cpp
> > index f85c3aa..5aa0eeb 100644
> > --- a/src/gstreamer/gstlibcamerapool.cpp
> > +++ b/src/gstreamer/gstlibcamerapool.cpp
> > @@ -18,6 +18,8 @@ struct _GstLibcameraPool {
> >  
> >  	GstAtomicQueue *queue;
> >  	GstLibcameraAllocator *allocator;
> > +	GstLibcameraBufferNotify buffer_notify;
> > +	gpointer buffer_notify_data;
> >  	Stream *stream;
> >  };
> >  
> > @@ -54,7 +56,12 @@ static void
> >  gst_libcamera_pool_release_buffer(GstBufferPool *pool, GstBuffer *buffer)
> >  {
> >  	GstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);
> > +	bool do_notify = gst_atomic_queue_length(self->queue) == 0;
> > +
> >  	gst_atomic_queue_push(self->queue, buffer);
> > +
> > +	if (do_notify && self->buffer_notify)
> > +		self->buffer_notify(self->buffer_notify_data);
> >  }
> >  
> >  static void
> > @@ -108,6 +115,15 @@ gst_libcamera_pool_new(GstLibcameraAllocator *allocator, Stream *stream)
> >  	return pool;
> >  }
> >  
> > +void
> > +gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
> > +				     GstLibcameraBufferNotify notify,
> > +				     gpointer data)
> > +{
> > +	self->buffer_notify = notify;
> > +	self->buffer_notify_data = data;
> > +}
> > +
> >  Stream *
> >  gst_libcamera_pool_get_stream(GstLibcameraPool *self)
> >  {
> > diff --git a/src/gstreamer/gstlibcamerapool.h b/src/gstreamer/gstlibcamerapool.h
> > index 6fd2913..545be01 100644
> > --- a/src/gstreamer/gstlibcamerapool.h
> > +++ b/src/gstreamer/gstlibcamerapool.h
> > @@ -20,9 +20,15 @@
> >  #define GST_TYPE_LIBCAMERA_POOL gst_libcamera_pool_get_type()
> >  G_DECLARE_FINAL_TYPE(GstLibcameraPool, gst_libcamera_pool, GST_LIBCAMERA, POOL, GstBufferPool)
> >  
> > +typedef void (*GstLibcameraBufferNotify)(gpointer data);
> > +
> >  GstLibcameraPool *gst_libcamera_pool_new(GstLibcameraAllocator *allocator,
> >  					 libcamera::Stream *stream);
> >  
> > +void gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
> > +					  GstLibcameraBufferNotify notify,
> > +					  gpointer data);
> > +
> >  libcamera::Stream *gst_libcamera_pool_get_stream(GstLibcameraPool *self);
> >  
> >  libcamera::Stream *gst_libcamera_buffer_get_stream(GstBuffer *buffer);
> > diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> > index fe60584..ecbfe37 100644
> > --- a/src/gstreamer/gstlibcamerasrc.cpp
> > +++ b/src/gstreamer/gstlibcamerasrc.cpp
> > @@ -434,6 +434,10 @@ gst_libcamera_src_task_enter(GstTask *task, GThread *thread, gpointer user_data)
> >  		const StreamConfiguration &stream_cfg = state->config->at(i);
> >  		GstLibcameraPool *pool = gst_libcamera_pool_new(self->allocator,
> >  								stream_cfg.stream());
> > +		gst_libcamera_pool_set_buffer_notify(pool,
> > +						     (GstLibcameraBufferNotify)gst_libcamera_resume_task,
> > +						     task);
> > +
> >  		gst_libcamera_pad_set_pool(srcpad, pool);
> >  		gst_flow_combiner_add_pad(self->flow_combiner, srcpad);
> >  	}
> > @@ -468,8 +472,14 @@ gst_libcamera_src_task_leave(GstTask *task, GThread *thread, gpointer user_data)
> >  
> >  	state->cam->stop();
> >  
> > -	for (GstPad *srcpad : state->srcpads)
> > -		gst_libcamera_pad_set_pool(srcpad, NULL);
> > +	for (GstPad *srcpad : state->srcpads) {
> > +		auto *pool = gst_libcamera_pad_get_pool(srcpad);
> > +
> > +		if (pool) {
> > +			gst_libcamera_pool_set_buffer_notify(pool, NULL, NULL);
> > +			gst_libcamera_pad_set_pool(srcpad, NULL);
> 
> s/NULL/nullptr/
> 
> Up to you, but you could also use a Signal. This would however require
> C++ objects, so some refactoring would be needed, and it may not be
> worth it, but adding ad-hoc callback registration is a step on the
> slippery slope to towards spaghetti code :-)

As this is a GObject, it could use a signal instead yes. I made that
comment internally to Jakub, but decided to send anyway. As I still
have many little typos and rebase errors, we'll have time to fix that
by then.

> 
> > +		}
> > +	}
> >  
> >  	g_clear_object(&self->allocator);
> >  	g_clear_pointer(&self->flow_combiner,
Laurent Pinchart March 2, 2020, 10:55 a.m. UTC | #3 
Hi Nicolas,

On Sat, Feb 29, 2020 at 10:35:21AM -0500, Nicolas Dufresne wrote:
> Le samedi 29 février 2020 à 17:11 +0200, Laurent Pinchart a écrit :
> > On Thu, Feb 27, 2020 at 03:04:06PM -0500, Nicolas Dufresne wrote:
> > > From: Jakub Adam <jakub.adam@collabora.com>
> > > 
> > > Allow GstLibcameraPool to notify the source when a new buffer has become
> > > available in a previously exhausted buffer pool. This can be used to
> > > resume a src task that got paused because it couldn't acquire a buffer.
> > > 
> > > Without this change the src task will never resume from pause once the
> > > pool gets exhausted.
> > > 
> > > To trigger the deadlock (it doesn't happen every time), run:
> > > 
> > >   gst-launch-1.0 libcamerasrc ! queue ! glimagesink
> > > 
> > > Signed-off-by: Jakub Adam <jakub.adam@collabora.com>
> > > ---
> > >  src/gstreamer/gstlibcamerapool.cpp | 16 ++++++++++++++++
> > >  src/gstreamer/gstlibcamerapool.h   |  6 ++++++
> > >  src/gstreamer/gstlibcamerasrc.cpp  | 14 ++++++++++++--
> > >  3 files changed, 34 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/src/gstreamer/gstlibcamerapool.cpp b/src/gstreamer/gstlibcamerapool.cpp
> > > index f85c3aa..5aa0eeb 100644
> > > --- a/src/gstreamer/gstlibcamerapool.cpp
> > > +++ b/src/gstreamer/gstlibcamerapool.cpp
> > > @@ -18,6 +18,8 @@ struct _GstLibcameraPool {
> > >  
> > >  	GstAtomicQueue *queue;
> > >  	GstLibcameraAllocator *allocator;
> > > +	GstLibcameraBufferNotify buffer_notify;
> > > +	gpointer buffer_notify_data;
> > >  	Stream *stream;
> > >  };
> > >  
> > > @@ -54,7 +56,12 @@ static void
> > >  gst_libcamera_pool_release_buffer(GstBufferPool *pool, GstBuffer *buffer)
> > >  {
> > >  	GstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);
> > > +	bool do_notify = gst_atomic_queue_length(self->queue) == 0;
> > > +
> > >  	gst_atomic_queue_push(self->queue, buffer);
> > > +
> > > +	if (do_notify && self->buffer_notify)
> > > +		self->buffer_notify(self->buffer_notify_data);
> > >  }
> > >  
> > >  static void
> > > @@ -108,6 +115,15 @@ gst_libcamera_pool_new(GstLibcameraAllocator *allocator, Stream *stream)
> > >  	return pool;
> > >  }
> > >  
> > > +void
> > > +gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
> > > +				     GstLibcameraBufferNotify notify,
> > > +				     gpointer data)
> > > +{
> > > +	self->buffer_notify = notify;
> > > +	self->buffer_notify_data = data;
> > > +}
> > > +
> > >  Stream *
> > >  gst_libcamera_pool_get_stream(GstLibcameraPool *self)
> > >  {
> > > diff --git a/src/gstreamer/gstlibcamerapool.h b/src/gstreamer/gstlibcamerapool.h
> > > index 6fd2913..545be01 100644
> > > --- a/src/gstreamer/gstlibcamerapool.h
> > > +++ b/src/gstreamer/gstlibcamerapool.h
> > > @@ -20,9 +20,15 @@
> > >  #define GST_TYPE_LIBCAMERA_POOL gst_libcamera_pool_get_type()
> > >  G_DECLARE_FINAL_TYPE(GstLibcameraPool, gst_libcamera_pool, GST_LIBCAMERA, POOL, GstBufferPool)
> > >  
> > > +typedef void (*GstLibcameraBufferNotify)(gpointer data);
> > > +
> > >  GstLibcameraPool *gst_libcamera_pool_new(GstLibcameraAllocator *allocator,
> > >  					 libcamera::Stream *stream);
> > >  
> > > +void gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
> > > +					  GstLibcameraBufferNotify notify,
> > > +					  gpointer data);
> > > +
> > >  libcamera::Stream *gst_libcamera_pool_get_stream(GstLibcameraPool *self);
> > >  
> > >  libcamera::Stream *gst_libcamera_buffer_get_stream(GstBuffer *buffer);
> > > diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> > > index fe60584..ecbfe37 100644
> > > --- a/src/gstreamer/gstlibcamerasrc.cpp
> > > +++ b/src/gstreamer/gstlibcamerasrc.cpp
> > > @@ -434,6 +434,10 @@ gst_libcamera_src_task_enter(GstTask *task, GThread *thread, gpointer user_data)
> > >  		const StreamConfiguration &stream_cfg = state->config->at(i);
> > >  		GstLibcameraPool *pool = gst_libcamera_pool_new(self->allocator,
> > >  								stream_cfg.stream());
> > > +		gst_libcamera_pool_set_buffer_notify(pool,
> > > +						     (GstLibcameraBufferNotify)gst_libcamera_resume_task,
> > > +						     task);
> > > +
> > >  		gst_libcamera_pad_set_pool(srcpad, pool);
> > >  		gst_flow_combiner_add_pad(self->flow_combiner, srcpad);
> > >  	}
> > > @@ -468,8 +472,14 @@ gst_libcamera_src_task_leave(GstTask *task, GThread *thread, gpointer user_data)
> > >  
> > >  	state->cam->stop();
> > >  
> > > -	for (GstPad *srcpad : state->srcpads)
> > > -		gst_libcamera_pad_set_pool(srcpad, NULL);
> > > +	for (GstPad *srcpad : state->srcpads) {
> > > +		auto *pool = gst_libcamera_pad_get_pool(srcpad);
> > > +
> > > +		if (pool) {
> > > +			gst_libcamera_pool_set_buffer_notify(pool, NULL, NULL);
> > > +			gst_libcamera_pad_set_pool(srcpad, NULL);
> > 
> > s/NULL/nullptr/
> > 
> > Up to you, but you could also use a Signal. This would however require
> > C++ objects, so some refactoring would be needed, and it may not be
> > worth it, but adding ad-hoc callback registration is a step on the
> > slippery slope to towards spaghetti code :-)
> 
> As this is a GObject, it could use a signal instead yes. I made that
> comment internally to Jakub, but decided to send anyway. As I still
> have many little typos and rebase errors, we'll have time to fix that
> by then.

I was referring to a libcamera Signal, but a glib signal works too :-)

> > > +		}
> > > +	}
> > >  
> > >  	g_clear_object(&self->allocator);
> > >  	g_clear_pointer(&self->flow_combiner,

Patch
diff mbox series 

diff --git a/src/gstreamer/gstlibcamerapool.cpp b/src/gstreamer/gstlibcamerapool.cpp
index f85c3aa..5aa0eeb 100644
--- a/src/gstreamer/gstlibcamerapool.cpp
+++ b/src/gstreamer/gstlibcamerapool.cpp
@@ -18,6 +18,8 @@  struct _GstLibcameraPool {
 
 	GstAtomicQueue *queue;
 	GstLibcameraAllocator *allocator;
+	GstLibcameraBufferNotify buffer_notify;
+	gpointer buffer_notify_data;
 	Stream *stream;
 };
 
@@ -54,7 +56,12 @@  static void
 gst_libcamera_pool_release_buffer(GstBufferPool *pool, GstBuffer *buffer)
 {
 	GstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);
+	bool do_notify = gst_atomic_queue_length(self->queue) == 0;
+
 	gst_atomic_queue_push(self->queue, buffer);
+
+	if (do_notify && self->buffer_notify)
+		self->buffer_notify(self->buffer_notify_data);
 }
 
 static void
@@ -108,6 +115,15 @@  gst_libcamera_pool_new(GstLibcameraAllocator *allocator, Stream *stream)
 	return pool;
 }
 
+void
+gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
+				     GstLibcameraBufferNotify notify,
+				     gpointer data)
+{
+	self->buffer_notify = notify;
+	self->buffer_notify_data = data;
+}
+
 Stream *
 gst_libcamera_pool_get_stream(GstLibcameraPool *self)
 {
diff --git a/src/gstreamer/gstlibcamerapool.h b/src/gstreamer/gstlibcamerapool.h
index 6fd2913..545be01 100644
--- a/src/gstreamer/gstlibcamerapool.h
+++ b/src/gstreamer/gstlibcamerapool.h
@@ -20,9 +20,15 @@ 
 #define GST_TYPE_LIBCAMERA_POOL gst_libcamera_pool_get_type()
 G_DECLARE_FINAL_TYPE(GstLibcameraPool, gst_libcamera_pool, GST_LIBCAMERA, POOL, GstBufferPool)
 
+typedef void (*GstLibcameraBufferNotify)(gpointer data);
+
 GstLibcameraPool *gst_libcamera_pool_new(GstLibcameraAllocator *allocator,
 					 libcamera::Stream *stream);
 
+void gst_libcamera_pool_set_buffer_notify(GstLibcameraPool *self,
+					  GstLibcameraBufferNotify notify,
+					  gpointer data);
+
 libcamera::Stream *gst_libcamera_pool_get_stream(GstLibcameraPool *self);
 
 libcamera::Stream *gst_libcamera_buffer_get_stream(GstBuffer *buffer);
diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index fe60584..ecbfe37 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -434,6 +434,10 @@  gst_libcamera_src_task_enter(GstTask *task, GThread *thread, gpointer user_data)
 		const StreamConfiguration &stream_cfg = state->config->at(i);
 		GstLibcameraPool *pool = gst_libcamera_pool_new(self->allocator,
 								stream_cfg.stream());
+		gst_libcamera_pool_set_buffer_notify(pool,
+						     (GstLibcameraBufferNotify)gst_libcamera_resume_task,
+						     task);
+
 		gst_libcamera_pad_set_pool(srcpad, pool);
 		gst_flow_combiner_add_pad(self->flow_combiner, srcpad);
 	}
@@ -468,8 +472,14 @@  gst_libcamera_src_task_leave(GstTask *task, GThread *thread, gpointer user_data)
 
 	state->cam->stop();
 
-	for (GstPad *srcpad : state->srcpads)
-		gst_libcamera_pad_set_pool(srcpad, NULL);
+	for (GstPad *srcpad : state->srcpads) {
+		auto *pool = gst_libcamera_pad_get_pool(srcpad);
+
+		if (pool) {
+			gst_libcamera_pool_set_buffer_notify(pool, NULL, NULL);
+			gst_libcamera_pad_set_pool(srcpad, NULL);
+		}
+	}
 
 	g_clear_object(&self->allocator);
 	g_clear_pointer(&self->flow_combiner,