sched/topology: Fix sched_numa_find_nth_cpu() in CPU-less case

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When the node provided by user is CPU-less, corresponding record in
sched_domains_numa_masks is not set. Trying to dereference it in the
following code leads to kernel crash.

To avoid it, start searching from the nearest node with CPUs.

Fixes: cd7f55359c ("sched: add sched_numa_find_nth_cpu()")
Reported-by: Yicong Yang <yangyicong@hisilicon.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Cc: Mel Gorman <mgorman@suse.de>
Link: https://lore.kernel.org/r/20230819141239.287290-4-yury.norov@gmail.com

Closes: https://lore.kernel.org/lkml/CAAH8bW8C5humYnfpW3y5ypwx0E-09A3QxFE1JFzR66v+mO4XfA@mail.gmail.com/T/
Closes: https://lore.kernel.org/lkml/ZMHSNQfv39HN068m@yury-ThinkPad/T/#mf6431cb0b7f6f05193c41adeee444bc95bf2b1c4

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Yury Norov 2023-08-19 07:12:35 -07:00 • committed by Ingo Molnar

parent d1db9fb432

commit 617f2c38cb

1 changed files with 5 additions and 1 deletions

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kernel/sched/topology.c

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