tracing: kprobes: Output kprobe event to printk buffer

Since kprobe-events use event_trigger_unlock_commit_regs() directly,
that events doesn't show up in printk buffer if "tp_printk" is set.

Use trace_event_buffer_commit() in kprobe events so that it can
invoke output_printk() as same as other trace events.

Link: http://lkml.kernel.org/r/157867233085.17873.5210928676787339604.stgit@devnote2Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
[ Adjusted data var declaration placement in __kretprobe_trace_func() ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

include/linux/trace_events.h

@@ -216,6 +216,7 @@ struct trace_event_buffer {
 	void				*entry;
 	unsigned long			flags;
 	int				pc;
+	struct pt_regs			*regs;
 };
 
 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,

kernel/trace/trace.c

@@ -2680,9 +2680,9 @@ void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
 	if (static_key_false(&tracepoint_printk_key.key))
 		output_printk(fbuffer);
 
-	event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
+	event_trigger_unlock_commit_regs(fbuffer->trace_file, fbuffer->buffer,
 				    fbuffer->event, fbuffer->entry,
-				    fbuffer->flags, fbuffer->pc);
+				    fbuffer->flags, fbuffer->pc, fbuffer->regs);
 }
 EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
 

kernel/trace/trace_events.c

@@ -272,6 +272,7 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 	if (!fbuffer->event)
 		return NULL;
 
+	fbuffer->regs = NULL;
 	fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 	return fbuffer->entry;
 }

kernel/trace/trace_kprobe.c

@@ -1175,35 +1175,35 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 		    struct trace_event_file *trace_file)
 {
 	struct kprobe_trace_entry_head *entry;
-	struct trace_buffer *buffer;
-	struct ring_buffer_event *event;
-	int size, dsize, pc;
-	unsigned long irq_flags;
 	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	struct trace_event_buffer fbuffer;
+	int dsize;
 
 	WARN_ON(call != trace_file->event_call);
 
 	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
-	local_save_flags(irq_flags);
-	pc = preempt_count();
+	local_save_flags(fbuffer.flags);
+	fbuffer.pc = preempt_count();
+	fbuffer.trace_file = trace_file;
 
 	dsize = __get_data_size(&tk->tp, regs);
-	size = sizeof(*entry) + tk->tp.size + dsize;
 
-	event = trace_event_buffer_lock_reserve(&buffer, trace_file,
-						call->event.type,
-						size, irq_flags, pc);
-	if (!event)
+	fbuffer.event =
+		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+					call->event.type,
+					sizeof(*entry) + tk->tp.size + dsize,
+					fbuffer.flags, fbuffer.pc);
+	if (!fbuffer.event)
 		return;
 
-	entry = ring_buffer_event_data(event);
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
 	entry->ip = (unsigned long)tk->rp.kp.addr;
 	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
 
-	event_trigger_unlock_commit_regs(trace_file, buffer, event,
-					 entry, irq_flags, pc, regs);
+	trace_event_buffer_commit(&fbuffer);
 }
 
 static void
@@ -1223,36 +1223,35 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 		       struct trace_event_file *trace_file)
 {
 	struct kretprobe_trace_entry_head *entry;
-	struct trace_buffer *buffer;
-	struct ring_buffer_event *event;
-	int size, pc, dsize;
-	unsigned long irq_flags;
+	struct trace_event_buffer fbuffer;
 	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	int dsize;
 
 	WARN_ON(call != trace_file->event_call);
 
 	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
-	local_save_flags(irq_flags);
-	pc = preempt_count();
+	local_save_flags(fbuffer.flags);
+	fbuffer.pc = preempt_count();
+	fbuffer.trace_file = trace_file;
 
 	dsize = __get_data_size(&tk->tp, regs);
-	size = sizeof(*entry) + tk->tp.size + dsize;
-
-	event = trace_event_buffer_lock_reserve(&buffer, trace_file,
-						call->event.type,
-						size, irq_flags, pc);
-	if (!event)
+	fbuffer.event =
+		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+					call->event.type,
+					sizeof(*entry) + tk->tp.size + dsize,
+					fbuffer.flags, fbuffer.pc);
+	if (!fbuffer.event)
 		return;
 
-	entry = ring_buffer_event_data(event);
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
 	entry->func = (unsigned long)tk->rp.kp.addr;
 	entry->ret_ip = (unsigned long)ri->ret_addr;
 	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
 
-	event_trigger_unlock_commit_regs(trace_file, buffer, event,
-					 entry, irq_flags, pc, regs);
+	trace_event_buffer_commit(&fbuffer);
 }
 
 static void