In PointerFinder we have the following code to determine if a pointer is in a TLAB:

        if (VM.getVM().getUseTLAB()) {
          // Try to find thread containing it
          for (int i = 0; i < threads.getNumberOfThreads(); i++) {
            JavaThread t = threads.getJavaThreadAt(i);
            ThreadLocalAllocBuffer tlab = t.tlab();
            if (tlab.contains(a)) {
              loc.inTLAB = true;
              loc.tlabThread = t;
              loc.tlab = tlab;
              break;
            }
          }

However, it is nested in a block of code that is only executed for the SerialGC. It should work for all GCs, and moving it outside of the SerialGC block should accomplish that.