| Message ID | 20230306204723.2584724-2-vernon2gm@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | fix call cpumask_next() if no further cpus set | expand |
diff --git a/drivers/char/random.c b/drivers/char/random.c index ce3ccd172cc8..253f2ddb8913 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1311,7 +1311,7 @@ static void __cold try_to_generate_entropy(void) /* Basic CPU round-robin, which avoids the current CPU. */ do { cpu = cpumask_next(cpu, &timer_cpus); - if (cpu == nr_cpumask_bits) + if (cpu >= nr_cpu_ids) cpu = cpumask_first(&timer_cpus); } while (cpu == smp_processor_id() && num_cpus > 1);
When cpumask_next() the return value is greater than or equal to nr_cpu_ids, it indicates invalid. Before commit 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask optimizations"), when cpumask_next() returned an invalid cpu, the driver used the judgment equal to nr_cpu_ids to indicate the invalid cpu, so it happened to work normally, but this is the wrong approach. After commit 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask optimizations"), these incorrect practices actively buggy, so fix it to correctly. Signed-off-by: Vernon Yang <vernon2gm@gmail.com> --- drivers/char/random.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)