On Wed, Sep 23, 2020 at 6:49 PM Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote: > > Hi Stanislav, > > looks like flow_dissector selftest got quite unstable recently. > test_link_update_invalid_opts:FAIL:340 > bpf_link_create(prog1): Argument list too long > #33/25 flow dissector link update invalid opts:FAIL > test_link_update_invalid_prog:FAIL:400 > bpf_link_create(prog1): Argument list too long > #33/26 flow dissector link update invalid prog:FAIL > #33/27 flow dissector link update netns gone:OK > I've seen similar flakiness for cgroup_link selftest that used to be rock solid. And it just clicked when I saw this, that this patch might be a culprit: https://patchwork.ozlabs.org/project/netdev/patch/20200917074453.20621-1-songmuchun@xxxxxxxxxxxxx/ It makes bpf_link detachment delayed, so now anything that relies on the fact that bpf_link gets auto-detached immediately after the last link FD was closed is flaky. But that is a pretty reasonable and convenient assumption. So can we please revert that patch? It's a really nice guarantee to have, while the benefits of the fix in that patch is a bit ephemeral. > It's failing for me half of the time with a random number of failures. > Not sure what happened. I think it was stable in the past. > To reproduce: > test_progs -t flow_dissector
