flock test fails on lustrefs

> $HOME/rr-build/bin/rr record $HOME/rr-build/bin/flock
rr: Saving execution to trace directory `/global/homes/k/kfischer/.local/share/rr/flock-7'.
parent pid is 61556
sizeof(flock) = 32
before lock: type: 2, pid: 0
  after lock: type: 0, pid: 61556
sizeof(flock64) = 32
before lock: type: 2, pid: 0
  after GETLK: type: 1, pid: 61556
P: forcing child to block on LK, sleeping ...
FAILED: errno=4 (Interrupted system call)
flock: /global/homes/k/kfischer/rr/src/test/flock.c:98: main: Assertion `"FAILED: !" && check_cond(0 == err)' failed.
P: ... awake, releasing lock
FAILED: errno=0 (Success)
flock: /global/homes/k/kfischer/rr/src/test/flock.c:120: main: Assertion `"FAILED: !" && check_cond(((((__extension__ (((union { __typeof(status) __in; int __i; }) { .__in = (status) }).__i))) & 0x7f) == 0) && 0 == ((((__extension__ (((union { __typeof(status) __in; int __i; }) { .__in = (status) }).__i))) & 0xff00) >> 8))' failed.
Aborted
> stat --file-system --format=%T .
lustre

Works fine without rr as well as with -n.
Mount options are rw,flock,lazystatfs in case it makes a difference.

Start with test/flock.c, especially the assertions around lines 98 and 120, and reproduce the command shown with rr record on a Lustre filesystem. Compare the failing run with execution without rr and with -n, then inspect the relevant rr behavior for flock and interrupted system calls. Done means the flock test passes under rr on Lustre without regressing the other two modes.