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([49.67.2.142]) by smtp.gmail.com with ESMTPSA id e23-20020aa78c57000000b005a75d85c0c7sm6699772pfd.51.2023.03.06.12.47.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Mar 2023 12:47:51 -0800 (PST) From: Vernon Yang To: torvalds@linux-foundation.org, tytso@mit.edu, Jason@zx2c4.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, jejb@linux.ibm.com, martin.petersen@oracle.com, yury.norov@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, james.smart@broadcom.com, dick.kennedy@broadcom.com Cc: linux-kernel@vger.kernel.org, wireguard@lists.zx2c4.com, netdev@vger.kernel.org, linux-scsi@vger.kernel.org, Vernon Yang Subject: [PATCH v2 1/4] random: fix try_to_generate_entropy() if no further cpus set Date: Tue, 7 Mar 2023 04:47:20 +0800 Message-Id: <20230306204723.2584724-2-vernon2gm@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230306204723.2584724-1-vernon2gm@gmail.com> References: <20230306204723.2584724-1-vernon2gm@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org 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 --- drivers/char/random.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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);