---

yaml
---
r: 121244
b: refs/heads/master
c: e49dc19
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7ee991fbc6f947e9b04f29c9c6c1d057d0671a16
+refs/heads/master: e49dc19c6a19ea112fcb94b7c62ec62cdd5c08aa

trunk/arch/x86/kernel/entry_32.S

@@ -1196,6 +1196,9 @@ ENTRY(mcount)
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	cmpl $ftrace_stub, ftrace_graph_return
 	jnz ftrace_graph_caller
+
+	cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
+	jnz ftrace_graph_caller
 #endif
 .globl ftrace_stub
 ftrace_stub:

trunk/arch/x86/kernel/entry_64.S

@@ -120,6 +120,9 @@ ENTRY(mcount)
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	cmpq $ftrace_stub, ftrace_graph_return
 	jnz ftrace_graph_caller
+
+	cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
+	jnz ftrace_graph_caller
 #endif
 
 .globl ftrace_stub

trunk/arch/x86/kernel/ftrace.c

@@ -425,6 +425,7 @@ static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
 	trace->calltime = current->ret_stack[index].calltime;
 	trace->overrun = atomic_read(&current->trace_overrun);
 	trace->depth = index;
+	barrier();
 	current->curr_ret_stack--;
 }
 
@@ -506,7 +507,11 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 	}
 
 	trace.func = self_addr;
-	ftrace_graph_entry(&trace);
 
+	/* Only trace if the calling function expects to */
+	if (!ftrace_graph_entry(&trace)) {
+		current->curr_ret_stack--;
+		*parent = old;
+	}
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */

trunk/include/linux/ftrace.h

@@ -371,7 +371,7 @@ struct ftrace_graph_ret {
 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 /* Type of the callback handlers for tracing function graph*/
 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
-typedef void (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
+typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 
 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 				trace_func_graph_ent_t entryfunc);

trunk/kernel/trace/ftrace.c

@@ -1636,11 +1636,15 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 
 static atomic_t ftrace_graph_active;
 
+int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
+{
+	return 0;
+}
+
 /* The callbacks that hook a function */
 trace_func_graph_ret_t ftrace_graph_return =
 			(trace_func_graph_ret_t)ftrace_stub;
-trace_func_graph_ent_t ftrace_graph_entry =
-			(trace_func_graph_ent_t)ftrace_stub;
+trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
 
 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
@@ -1738,7 +1742,7 @@ void unregister_ftrace_graph(void)
 
 	atomic_dec(&ftrace_graph_active);
 	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
-	ftrace_graph_entry = (trace_func_graph_ent_t)ftrace_stub;
+	ftrace_graph_entry = ftrace_graph_entry_stub;
 	ftrace_shutdown(FTRACE_STOP_FUNC_RET);
 
 	mutex_unlock(&ftrace_sysctl_lock);

trunk/kernel/trace/trace.c

@@ -1200,7 +1200,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip)
 }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-void trace_graph_entry(struct ftrace_graph_ent *trace)
+int trace_graph_entry(struct ftrace_graph_ent *trace)
 {
 	struct trace_array *tr = &global_trace;
 	struct trace_array_cpu *data;
@@ -1219,6 +1219,8 @@ void trace_graph_entry(struct ftrace_graph_ent *trace)
 	}
 	atomic_dec(&data->disabled);
 	local_irq_restore(flags);
+
+	return 1;
 }
 
 void trace_graph_return(struct ftrace_graph_ret *trace)

trunk/kernel/trace/trace.h

@@ -412,7 +412,7 @@ void trace_function(struct trace_array *tr,
 		    unsigned long flags, int pc);
 
 void trace_graph_return(struct ftrace_graph_ret *trace);
-void trace_graph_entry(struct ftrace_graph_ent *trace);
+int trace_graph_entry(struct ftrace_graph_ent *trace);
 void trace_bts(struct trace_array *tr,
 	       unsigned long from,
 	       unsigned long to);