Re: [PATCH v4 1/2] sched/topology: Don't try to build empty sched domains

[Valentin Schneider]

On 24/10/2019 17:19, Dietmar Eggemann wrote:
> Sorry for being picky but IMHO you should also mention that it fixes
> 
> f9a25f776d78 ("cpusets: Rebuild root domain deadline accounting
> information")
> 

I can append the following to the changelog, although I'd like some
feedback from the cgroup folks before doing a respin:

"""
Note that commit

  f9a25f776d78 ("cpusets: Rebuild root domain deadline accounting information")

introduced a similar issue. Since doms_new is assigned to doms_cur without
any filtering, we can end up with an empty cpumask in the doms_cur array.

The next time we go through a rebuild, this will break on:

  rd = cpu_rq(cpumask_any(doms_cur[i]))->rd;

If there wasn't enough already, this is yet another argument for *not*
handing over empty cpumasks to the sched domain rebuild.
"""

I tagged the commit that introduces the static key with Fixes: because it
was introduced earlier - I don't think it would make sense to have two
"Fixes:" lines? In any case, it'll now be listed in the changelog.