Re: [PATCH sched_ext v2 1/2] sched_ext: make DSQ iterator stay drained after NULL

[Tejun Heo]

Hello, Kang.

v1 is already applied to sched_ext/for-7.4-fixes.

The selftest doesn't catch the bug reliably. Every ops.dequeue() invocation
overwrites next_after_drain and the test reads it once at the end. If the
last invocation saw an empty DSQ, the restarted walk returns NULL too and
the test passes on a kernel without the fix. Here, it passed about half of
the runs on an idle VM without the fix.

Also, I don't think the selftest is all that useful.

Thanks.

--
tejun