open O_TMPFILE fails in gem5 syscall emulation with "Assertion `0 <= tgt_fd && tgt_fd < _fdArray.size()' failed"

[cirosantilli]

As of LKMC 6936bd6 and gem5 master 8549ee4a6dfc86a941cee0a478c01f6f2c146c3c:

./run --arch aarch64 --emulator gem5 --static --userland userland/linux/open_o_tmpfile.c --gem5-worktree master

fails with:

/path/to/linux-kernel-module-cheat/out/gem5/master/build/ARM/sim/fd_array.cc:322: std::shared_ptr<FDEntry> FDArray::getFDEntry(int): Assertion `0 <= tgt_fd && tgt_fd < _fdArray.size()' failed.