Fix GPU collector

Author: gnurizen

parcagpu/parcagpu.go

@@ -111,7 +111,7 @@ func Start(ctx context.Context, tr *tracer.Tracer,
 		var cbid int32
 		for frames := libpf.EbpfFrame(rawTrace.FrameData); len(frames) > 0; frames = frames[frames.Length():] {
 			if frames.Type() == libpf.CUDAKernelFrame {
-				lineno := frames.Data()
+				lineno := frames.Variable(0)
 				correlationID = uint32(lineno)
 				cbid = int32(lineno >> 32)
 				break

processmanager/manager.go

@@ -260,7 +260,7 @@ func (pm *ProcessManager) convertFrame(pid libpf.PID, ef libpf.EbpfFrame, dst *l
 		// Preserve AddressOrLineno which encodes correlation ID | (CBID << 32).
 		dst.Append(&libpf.Frame{
 			Type:            ef.Type(),
-			AddressOrLineno: libpf.AddressOrLineno(ef.Data()),
+			AddressOrLineno: libpf.AddressOrLineno(ef.Variable(0)),
 		})
 	default:
 		err := pm.symbolizeFrame(pid, ef, dst, libpf.FrameMapping{})

support/ebpf/tracemgmt.h

@@ -787,12 +787,10 @@ static inline EBPF_INLINE int collect_trace(
   if (cuda_id != 0) {
     // Create a CUDA kernel frame, Symbolize will later resolve the kernel name from the ID.
     u64 *data =
-      push_frame(&record->state, trace, FRAME_MARKER_CUDA_KERNEL, FRAME_FLAG_PID_SPECIFIC, 0, 2);
+      push_frame(&record->state, trace, FRAME_MARKER_CUDA_KERNEL, FRAME_FLAG_PID_SPECIFIC, 0, 1);
     if (!data)
       return ERR_STACK_LENGTH_EXCEEDED;
     data[0] = cuda_id;
-    // this is used by userland to stash the kernel name pointer
-    data[1] = 0;
   }
 
   // Recursive unwind frames