failing tests on debian9.4

hi,
I am running on debian 9.4.
I built the package as explained on install.md, and I had some problems:
1. The tests brb and brb2 just got stuck. After an hour it seemed strange, so I wanted to strace them to see if there is an activity. I saw that there is two process that run the test script, and the first was stuck on futex and the other on restart_syscall on a poll. It was the same for both tests.
2. On test_tools_smoke, 2 tools failed - mdflush and uthreads.
mdflush gave this output - cannot attach kprobe, probe entry may not exist. The relevant probe is md_flush_request. I checked on the source of the kernel of my version (4.9.88) and the function exists.
uthreads gave the following output:
Error attaching USDT probes: the specified pid might not contain the
given language's runtime, or the runtime was not built with the required
USDT probes. Look for a configure flag similar to --with-dtrace or
--enable-dtrace. To check which probes are present in the process, use the
tplist tool.

Any idea why this might happen?

Thank you