From: Tero Kristo tero.kristo@linux.intel.com

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@linux.intel... Link: https://lkml.kernel.org/r/20230310100451.3948583-2-tero.kristo@linux.intel.c...

Cc: stable@vger.kernel.org Fixes: f46b16520a087 ("trace/hwlat: Implement the per-cpu mode") Signed-off-by: Tero Kristo tero.kristo@linux.intel.com Acked-by: Daniel Bristot de Oliveira bristot@kernel.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- kernel/trace/trace_hwlat.c | 3 --- 1 file changed, 3 deletions(-)

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index d440ddd5fd8b..edc26dc22c3f 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -584,9 +584,6 @@ static int start_per_cpu_kthreads(struct trace_array *tr) */ 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)