GPU: make ITS framework allocator thread-safe

Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch>

Author: f3sch

GPU/GPUTracking/Global/GPUChainITS.cxx

@@ -17,7 +17,7 @@
 #include "DataFormatsITS/TrackITS.h"
 #include "ITStracking/ExternalAllocator.h"
 #include "GPUReconstructionIncludesITS.h"
-#include <algorithm>
+#include <mutex>
 
 using namespace o2::gpu;
 
@@ -28,13 +28,15 @@ class GPUFrameworkExternalAllocator final : public o2::its::ExternalAllocator
  public:
   void* allocate(size_t size) override
   {
+    std::scoped_lock lck(mLock);
     return mFWReco->AllocateDirectMemory(size, GPUMemoryResource::MEMORY_GPU);
   }
   void deallocate(char* ptr, size_t) override {}
   void setReconstructionFramework(o2::gpu::GPUReconstruction* fwr) { mFWReco = fwr; }
 
  private:
   o2::gpu::GPUReconstruction* mFWReco;
+  std::mutex mLock;
 };
 } // namespace o2::its