On Fri, 5 Jun 2026 00:40:06 +0000 Samuel Moelius <[email protected]> wrote:
> preemptirq_delay_test accepts cpu_affinity as a module parameter and, > when it is non-negative, writes that CPU directly into a temporary > cpumask from the worker thread. Values outside nr_cpu_ids can set a > bit outside the allocated cpumask before the test reports a normal > affinity error. > > Validate the requested CPU before starting the worker thread, and > return -EINVAL for invalid affinity requests. > > Assisted-by: Codex:gpt-5.5-cyber-preview > Signed-off-by: Samuel Moelius <[email protected]> > --- > kernel/trace/preemptirq_delay_test.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/kernel/trace/preemptirq_delay_test.c > b/kernel/trace/preemptirq_delay_test.c > index acb0c971a408..0f017799754a 100644 > --- a/kernel/trace/preemptirq_delay_test.c > +++ b/kernel/trace/preemptirq_delay_test.c > @@ -14,6 +14,7 @@ > #include <linux/kthread.h> > #include <linux/module.h> > #include <linux/printk.h> > +#include <linux/cpumask.h> > #include <linux/string.h> > #include <linux/sysfs.h> > #include <linux/completion.h> > @@ -152,6 +153,15 @@ static int preemptirq_run_test(void) > struct task_struct *task; > char task_name[50]; > > + if (cpu_affinity > -1) { > + unsigned int cpu = cpu_affinity; > + > + if (cpu >= nr_cpu_ids || !cpu_possible(cpu)) { > + pr_err("cpu_affinity:%d, invalid CPU\n", cpu_affinity); > + return -EINVAL; Just add the check to the preemptirq_delay_run() function where it tests affinity. Who cares if it created the thread or not. It's just a test. -- Steve > + } > + } > + > init_completion(&done); > > snprintf(task_name, sizeof(task_name), "%s_test", test_mode);
