Commit 97b17efe authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
Browse files

ring-buffer: do not swap if recording is disabled 



If the ring buffer recording has been disabled. Do not let
swapping of ring buffers occur. Simply return -EAGAIN.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 5bc4564b

kernel/trace/ring_buffer.c

+15 −0
Original line number Diff line number Diff line
@@ -2266,9 +2266,24 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 
	if (buffer_a->pages != buffer_b->pages)

		return -EINVAL;



	if (ring_buffer_flags != RB_BUFFERS_ON)

		return -EAGAIN;



	if (atomic_read(&buffer_a->record_disabled))

		return -EAGAIN;



	if (atomic_read(&buffer_b->record_disabled))

		return -EAGAIN;



	cpu_buffer_a = buffer_a->buffers[cpu];

	cpu_buffer_b = buffer_b->buffers[cpu];



	if (atomic_read(&cpu_buffer_a->record_disabled))

		return -EAGAIN;



	if (atomic_read(&cpu_buffer_b->record_disabled))

		return -EAGAIN;



	/*

	 * We can't do a synchronize_sched here because this

	 * function can be called in atomic context.

kernel/trace/trace.c

+1 −1
Original line number Diff line number Diff line
@@ -415,7 +415,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) 


	ftrace_enable_cpu();



	WARN_ON_ONCE(ret);

	WARN_ON_ONCE(ret && ret != -EAGAIN);



	__update_max_tr(tr, tsk, cpu);

	__raw_spin_unlock(&ftrace_max_lock);