tracing: Add build bug if we have more trace_flags than bits
Add a enum that denotes the last bit of the trace_flags and have a
BUILD_BUG_ON(last_bit > 32).
If we add more bits than we have in trace_flags, the kernel wont build.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7446d42..991bab9 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7046,6 +7046,12 @@
int ring_buf_size;
int ret = -ENOMEM;
+ /*
+ * Make sure we don't accidently add more trace options
+ * than we have bits for.
+ */
+ BUILD_BUG_ON(TRACE_ITER_LAST_BIT > 32);
+
if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
goto out;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8ed9787..0715565 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -966,7 +966,11 @@
#undef C
#define C(a, b) TRACE_ITER_##a##_BIT
-enum trace_iterator_bits { TRACE_FLAGS };
+enum trace_iterator_bits {
+ TRACE_FLAGS
+ /* Make sure we don't go more than we have bits for */
+ TRACE_ITER_LAST_BIT
+};
/*
* By redefining C, we can make TRACE_FLAGS a list of masks that