osnoise_hotplug_workfn() is the asynchronous online callback for
"trace/osnoise:online". It may be congested when a CPU goes online and
offline repeatedly and is invoked for multiple times after a certain
online.
This will lead to kthread leak and timer corruption. Add a check
in start_kthread() to prevent this situation.
Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations")
Signed-off-by: Wei Li <liwei...@huawei.com>
---
kernel/trace/trace_osnoise.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 7e75c1214b36..934a14bc72e6 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -2007,6 +2007,10 @@ static int start_kthread(unsigned int cpu)
void *main = osnoise_main;
char comm[24];
+ /* Do not start a new thread if it is already running */
+ if (per_cpu(per_cpu_osnoise_var, cpu).kthread)
+ return 0;
+
if (timerlat_enabled()) {
snprintf(comm, 24, "timerlat/%d", cpu);
main = timerlat_main;
@@ -2061,11 +2065,10 @@ static int start_per_cpu_kthreads(void)
if (cpumask_test_and_clear_cpu(cpu, &kthread_cpumask)) {
struct task_struct *kthread;
- kthread = per_cpu(per_cpu_osnoise_var, cpu).kthread;
+ kthread = xchg_relaxed(&(per_cpu(per_cpu_osnoise_var,
cpu).kthread), NULL);
if (!WARN_ON(!kthread))
kthread_stop(kthread);
}
- per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL;
}
for_each_cpu(cpu, current_mask) {
--
2.25.1
