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: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0b9de5a..890020e 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2266,9 +2266,24 @@
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.
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 220c264..757ae6f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -415,7 +415,7 @@
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);