atime, mtime from ebpf are buggy

[haesbaert]

I get this from time to time:

$ make && sudo -b ./quark-test t_file
make: Nothing to be done for 'all'.
eru:quark: t_file @ ebpf................failed
exited with signal 6 (Aborted)
qf->atime=1753113129559708738, st.st_atim=1753113129558489630
qf->atime=(null) <----- this is a ctime call
st.st_atim=Mon Jul 21 17:52:09 2025 <----- this is a ctime call

quark-test: quark-test.c:801: t_file: Assertion `qf->atime == TS_TO_NS(&st.st_atim)' failed.

Looks like a signed vs unsigned, the lower 32bit are corrupted from time to time.