tracing: Have trace buffer point back to trace_array

The trace buffer has a descriptor pointer that goes back to the trace
array. But it was never assigned. Luckily, nothing uses it (yet), but
it will in the future.

Although nothing currently uses this, if any of the new features get
backported to older kernels, and because this is such a simple change,
I'm marking it for stable too.

Cc: stable@vger.kernel.org # v3.10+
Fixes: 12883efb670c "tracing: Consolidate max_tr into main trace_array structure"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e32a2f48dde123ad9036f3998c63835140f3d5e9..cee9c1a552ab5ed2f62d725eff46251dd28ea72e 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5914,6 +5914,8 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
 
        rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
 
+       buf->tr = tr;
+
        buf->buffer = ring_buffer_alloc(size, rb_flags);
        if (!buf->buffer)
                return -ENOMEM;