[for-next][PATCH 2/7] function_graph: Handle TRACE_BPUTS in print_graph_comment

From: Steven Rostedt
Date: Tue Sep 06 2016 - 09:41:46 EST


From: Namhyung Kim <namhyung@xxxxxxxxxx>

It missed to handle TRACE_BPUTS so messages recorded by trace_bputs()
will be shown with symbol info unnecessarily.

You can see it with the trace_printk sample code:

# cd /sys/kernel/tracing/
# echo sys_sync > set_graph_function
# echo 1 > options/sym-offset
# echo function_graph > current_tracer

Note that the sys_sync filter was there to prevent recording other
functions and the sym-offset option was needed since the first message
was called from a module init function so kallsyms doesn't have the
symbol and omitted in the output.

# cd ~/build/kernel
# insmod samples/trace_printk/trace-printk.ko

# cd -
# head trace

Before:

# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
1) | /* 0xffffffffa0002000: This is a static string that will use trace_bputs */
1) | /* This is a dynamic string that will use trace_puts */
1) | /* trace_printk_irq_work+0x5/0x7b [trace_printk]: (irq) This is a static string that will use trace_bputs */
1) | /* (irq) This is a dynamic string that will use trace_puts */
1) | /* (irq) This is a static string that will use trace_bprintk() */
1) | /* (irq) This is a dynamic string that will use trace_printk */

After:

# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
1) | /* This is a static string that will use trace_bputs */
1) | /* This is a dynamic string that will use trace_puts */
1) | /* (irq) This is a static string that will use trace_bputs */
1) | /* (irq) This is a dynamic string that will use trace_puts */
1) | /* (irq) This is a static string that will use trace_bprintk() */
1) | /* (irq) This is a dynamic string that will use trace_printk */

Link: http://lkml.kernel.org/r/20160901024354.13720-1-namhyung@xxxxxxxxxx

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_functions_graph.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 7363ccf79512..e14017c36170 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1120,6 +1120,11 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
trace_seq_puts(s, "/* ");

switch (iter->ent->type) {
+ case TRACE_BPUTS:
+ ret = trace_print_bputs_msg_only(iter);
+ if (ret != TRACE_TYPE_HANDLED)
+ return ret;
+ break;
case TRACE_BPRINT:
ret = trace_print_bprintk_msg_only(iter);
if (ret != TRACE_TYPE_HANDLED)
--
2.8.1