[PATCH 1/3] tracing: add ftrace_trace_stack into __trace_puts/__trace_bputs

["zhangwei(Jovi)" <jovi.zhangwei@huawei.com>]

Currently trace option stacktrace is not applicable for
trace_printk with constant string argument, the reason is
there missed ftrace_trace_stack in __trace_puts/__trace_bputs.

In contrast, when using trace_printk with not constant string
argument(will call into __trace_printk/__trace_bprintk), then
trace option stacktrace is workable, this inconstant result
will confusing user a lot.

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
---
 kernel/trace/trace.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3d5a931..4d70cc5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -363,13 +363,16 @@ int __trace_puts(unsigned long ip, const char *str, int size)
 	struct print_entry *entry;
 	unsigned long irq_flags;
 	int alloc;
+	int pc;
+
+	pc = preempt_count();

 	alloc = sizeof(*entry) + size + 2; /* possible \n added */

 	local_save_flags(irq_flags);
 	buffer = global_trace.trace_buffer.buffer;
 	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
-					  irq_flags, preempt_count());
+					  irq_flags, pc);
 	if (!event)
 		return 0;

@@ -386,6 +389,7 @@ int __trace_puts(unsigned long ip, const char *str, int size)
 		entry->buf[size] = '\0';

 	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(buffer, irq_flags, 4, pc);

 	return size;
 }
@@ -403,11 +407,14 @@ int __trace_bputs(unsigned long ip, const char *str)
 	struct bputs_entry *entry;
 	unsigned long irq_flags;
 	int size = sizeof(struct bputs_entry);
+	int pc;
+
+	pc = preempt_count();

 	local_save_flags(irq_flags);
 	buffer = global_trace.trace_buffer.buffer;
 	event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
-					  irq_flags, preempt_count());
+					  irq_flags, pc);
 	if (!event)
 		return 0;

@@ -416,6 +423,7 @@ int __trace_bputs(unsigned long ip, const char *str)
 	entry->str			= str;

 	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(buffer, irq_flags, 4, pc);

 	return 1;
 }
-- 
1.7.9.7