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sched/topology: Handle NUMA_NO_NODE in sched_numa_find_nth_cpu() 

sched_numa_find_nth_cpu() doesn't handle NUMA_NO_NODE properly, and
may crash kernel if passed with it. On the other hand, the only user
of sched_numa_find_nth_cpu() has to check NUMA_NO_NODE case explicitly.

It would be easier for users if this logic will get moved into
sched_numa_find_nth_cpu().

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Link: https://lore.kernel.org/r/20230819141239.287290-6-yury.norov@gmail.com
This commit is contained in:
Yury Norov 2023-08-19 07:12:37 -07:00 committed by Ingo Molnar
parent 8ab63d418d
commit 9ecea9ae4d
2 changed files with 4 additions and 3 deletions
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3
kernel/sched/topology.c
View File

@ -2126,6 +2126,9 @@ int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node)
struct cpumask ***hop_masks;
int hop, ret = nr_cpu_ids;
if (node == NUMA_NO_NODE)
return cpumask_nth_and(cpu, cpus, cpu_online_mask);
rcu_read_lock();
/* CPU-less node entries are uninitialized in sched_domains_numa_masks */

4
lib/cpumask.c
View File

@ -146,9 +146,7 @@ unsigned int cpumask_local_spread(unsigned int i, int node)
/* Wrap: we always want a cpu. */
i %= num_online_cpus();
cpu = (node == NUMA_NO_NODE) ?
cpumask_nth(i, cpu_online_mask) :
sched_numa_find_nth_cpu(cpu_online_mask, i, node);
cpu = sched_numa_find_nth_cpu(cpu_online_mask, i, node);
WARN_ON(cpu >= nr_cpu_ids);
return cpu;