[PATCH AUTOSEL 6.2 09/30] cpumask: fix incorrect cpumask scanning result checks

[Linus Torvalds]

On Sun, Mar 19, 2023 at 5:53 PM Sasha Levin <sashal at kernel.org> wrote:
>
> [ Upstream commit 8ca09d5fa3549d142c2080a72a4c70ce389163cd ]

These are technically real fixes, but they are really just "documented
behavior" fixes, and don't actually matter unless you also have
596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask
optimizations"), which doesn't look like stable material.

And if somebody *does* decide to backport commit 596ff4a09b89, you
should then backport all of

  6015b1aca1a2 sched_getaffinity: don't assume 'cpumask_size()' is
fully initialized
  e7304080e0e5 cpumask: relax sanity checking constraints
  63355b9884b3 cpumask: be more careful with 'cpumask_setall()'
  8ca09d5fa354 cpumask: fix incorrect cpumask scanning result checks

but again, none of these matter as long as the constant-sized cpumask
optimized case doesn't exist.

(Technically, FORCE_NR_CPUS also does the constant-size optimizations
even before, but that will complain loudly if that constant size then
doesn't match nr_cpu_ids, so ..).

                   Linus