From: Tero Kristo <tero.kristo@xxxxxxxxxxxxxxx> commit 4c42f5f0d1dd20bddd9f940beb1e6ccad60c4498 upstream. Do not wipe the contents of the per-cpu kthread data when starting the tracer, as this will completely forget about already running instances and can later start new additional per-cpu threads. Link: https://lore.kernel.org/all/20230302113654.2984709-1-tero.kristo@xxxxxxxxxxxxxxx/ Link: https://lkml.kernel.org/r/20230310100451.3948583-2-tero.kristo@xxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Fixes: f46b16520a087 ("trace/hwlat: Implement the per-cpu mode") Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxxxxxxxx> Acked-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/trace_hwlat.c | 3 --- 1 file changed, 3 deletions(-) --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -588,9 +588,6 @@ static int start_per_cpu_kthreads(struct */ cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask); - for_each_online_cpu(cpu) - per_cpu(hwlat_per_cpu_data, cpu).kthread = NULL; - for_each_cpu(cpu, current_mask) { retval = start_cpu_kthread(cpu); if (retval)
