Re: [PATCH net] selftests: rtnetlink: fix addrlft test flakiness on power-saving systems

[Hangbin Liu <liuhangbin@gmail.com>]

On Mon, Aug 18, 2025 at 06:30:12PM -0700, Jakub Kicinski wrote:
> On Tue, 15 Jul 2025 04:34:59 +0000 Hangbin Liu wrote:
> > Jakub reported that the rtnetlink test for the preferred lifetime of an
> > address has become quite flaky. The issue started appearing around the 6.16
> > merge window in May, and the test fails with:
> > 
> >     FAIL: preferred_lft addresses remaining
> > 
> > The flakiness might be related to power-saving behavior, as address
> > expiration is handled by a "power-efficient" workqueue.
> > 
> > To address this, use slowwait to check more frequently whether the address
> > still exists. This reduces the likelihood of the system entering a low-power
> > state during the test, improving reliability.
> 
> It flaked again, after long time of being fine..
> 
> https://netdev-3.bots.linux.dev/vmksft-net/results/259361/15-rtnetlink-sh/stdout

Hmm, I think we need to know what's the current preferred_lft and valid_lft
on failed test. Would you please add a debug line so we can get the info
after failed?

        slowwait 5 check_addr_not_exist "$devdummy" "10.23.11."
        if [ $? -eq 1 ]; then
+               ip addr show dev "$devdummy"
                check_err 1
                end_test "FAIL: preferred_lft addresses remaining"
                return

Thanks
Hangbin