fanotify09 failed on arm64 devices running 4.14 version kernel fanotify09.c:202: FAIL: first group got more than 2 events (72 > 48) https://bugs.linaro.org/show_bug.cgi?id=4271
fanotify09 was added a new regression test case for commit b469e7e47c8a: fanotify: fix handling of events on child sub-directory
That commit was backported to v4.19. As I wrote in "backport hint", the bug exists in older kernels, but fix does not apply cleanly to older kernels.
If someone were to provide a tested backport to 4.14 and older, I'll be glad to queue it up (hint hint hint...)
Attached backport applies and tested on 4.14 and 4.9
Thanks, Amir.