bpf: Forbid bpf_ktime_get_coarse_ns and bpf_timer_* in tracing progs

[linux-2.6-microblaze.git] / kernel / trace / ring_buffer.c

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f6520d0..2699e9e 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -5228,6 +5228,9 @@ void ring_buffer_reset(struct trace_buffer *buffer)
        struct ring_buffer_per_cpu *cpu_buffer;
        int cpu;
 
+       /* prevent another thread from changing buffer sizes */
+       mutex_lock(&buffer->mutex);
+
        for_each_buffer_cpu(buffer, cpu) {
                cpu_buffer = buffer->buffers[cpu];
 
@@ -5246,6 +5249,8 @@ void ring_buffer_reset(struct trace_buffer *buffer)
                atomic_dec(&cpu_buffer->record_disabled);
                atomic_dec(&cpu_buffer->resize_disabled);
        }
+
+       mutex_unlock(&buffer->mutex);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_reset);