[libcamera-devel] [PATCH 2/3] libcamera: pipeline: ipu3: Ensure that IPU3Frames::info is not used after delete

[Kieran Bingham]

When the IPU3Frames completes, it deletes the internal info storage.

This storage contains the pointer to the Request, but in some cases the
pointer was being accessed after the info structure was removed.

Ensure that the Request is obtained before attempting to complete to
obtain a valid pointer.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

---
This may be a further sign that we should rework how this is allocated,
but for now - this patch fixes the crash which can occur when shutting
down streams.


    The blank line addition in the first hunk is intentional.


 src/libcamera/pipeline/ipu3/ipu3.cpp | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 2b4d31500533..9539393e5d84 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -1164,6 +1164,7 @@ void IPU3CameraData::queueFrameAction(unsigned int id,
 		 * in action.controls to register additional metadata.
 		 */
 		Request *request = info->request;
+
 		info->metadataProcessed = true;
 		if (frameInfos_.tryComplete(info))
 			pipe_->completeRequest(request);
@@ -1253,8 +1254,15 @@ void IPU3CameraData::paramBufferReady(FrameBuffer *buffer)
 		return;
 
 	info->paramDequeued = true;
+
+	/*
+	 * tryComplete() will delete info if it completes the IPU3Frame.
+	 * In that event, we must have obtained the Request before hand.
+	 */
+	Request *request = info->request;
+
 	if (frameInfos_.tryComplete(info))
-		pipe_->completeRequest(info->request);
+		pipe_->completeRequest(request);
 }
 
 void IPU3CameraData::statBufferReady(FrameBuffer *buffer)
@@ -1265,8 +1273,16 @@ void IPU3CameraData::statBufferReady(FrameBuffer *buffer)
 
 	if (buffer->metadata().status == FrameMetadata::FrameCancelled) {
 		info->metadataProcessed = true;
+
+		/*
+		* tryComplete() will delete info if it completes the IPU3Frame.
+		* In that event, we must have obtained the Request before hand.
+		*/
+		Request *request = info->request;
+
 		if (frameInfos_.tryComplete(info))
-			pipe_->completeRequest(info->request);
+			pipe_->completeRequest(request);
+
 		return;
 	}
 
-- 
2.25.1