[for-next][PATCH 01/18] tracing: Only allow trace_array_printk() to be used by instances

Steven Rostedt
2020-07-02T21:59:22Z

To prevent default "trace_printks()" from spamming the top level tracing
ring buffer, only allow trace instances to use trace_array_printk() (which
can be used without the trace_printk() start up warning).

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bb62269724d5..8241d1448d70 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3346,12 +3346,16 @@ int trace_array_printk(struct trace_array *tr,
int ret;
va_list ap;

- if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
- return 0;
-
if (!tr)
return -ENOENT;

+ /* This is only allowed for created instances */
+ if (tr == &global_trace)
+ return 0;
+
+ if (!(tr->trace_flags & TRACE_ITER_PRINTK))
+ return 0;
+
va_start(ap, fmt);
ret = trace_array_vprintk(tr, ip, fmt, ap);
va_end(ap);
--
2.26.2