[Libguestfs] Memory corruption when testing nbdkit python plugin with nbd-tester-client?

Hi, has anyone ever run "make check" from nbd against nbdkit with a python plugin? I usually get segfaults during such a run, and sometimes various other errors happen before the segfault, suggesting that some memory corruption is underway. AFAICS a pure python plugin should not be able to cause memory corruption. Examples of nbdkit logs for running "make check" or subsets of it from nbd against nbdkit: nbdkit -n -f python script=ssd-ftl-wearleveling.py disksize=52428800 nbdkit: python[6]: error: ssd-ftl-wearleveling.py: callback failed: close nbdkit: python[7]: error: invalid flush request: expecting offset and length == 0 nbdkit: python[7]: error: write reply: Connection reset by peer Segmentation fault nbdkit -n -f python script=ssd-ftl-wearleveling.py disksize=52428800 Fatal Python error: GC object already tracked Segmentation fault nbdkit -n -f python script=ssd-ftl-wearleveling.py disksize=52428800 Segmentation fault nbdkit -n -f python script=ssd-ftl-wearleveling.py disksize=52428800 nbdkit: python[1]: error: invalid flush request: expecting offset and length == 0 nbdkit: python[1]: error: write reply: Broken pipe nbdkit: python[3]: error: client sent NBD_OPT_ABORT to abort the connection nbdkit: python[6]: error: ssd-ftl-wearleveling.py: callback failed: close Traceback (most recent call last): File "ssd-ftl-wearleveling.py", line 221, in close pickle.dump(lbahist, f) File "/usr/lib/python2.7/pickle.py", line 1370, in dump Segmentation fault (core dumped) My close function just dumps the disk image and write access history with python pickle. It does not have any return statement, and because of that I seriously doubt that said close function can fail. I'm now trying to replicate this with example.py. Will report back. Regards, Carl-Daniel