In preparation to the hotplug support on tracers with workload, protect tr->tracing_cpumask with get/put_online_cpus() to avoid concurrency with hotplug operations. Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx> Cc: Clark Willaims <williams@xxxxxxxxxx> Cc: John Kacur <jkacur@xxxxxxxxxx> Cc: Juri Lelli <juri.lelli@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: x86@xxxxxxxxxx Cc: linux-doc@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> --- kernel/trace/trace.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 52fc9438b7b4..c14f33db147e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5053,7 +5053,13 @@ int tracing_set_cpumask(struct trace_array *tr, arch_spin_unlock(&tr->max_lock); local_irq_enable(); + /* + * tracing_cpumask is read by tracers that support CPU + * hotplug. + */ + get_online_cpus(); cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new); + put_online_cpus(); return 0; } -- 2.31.1
