4 files changed, 62 insertions, 3 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3b8c0e24ab30..447bd96ee658 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -512,12 +512,44 @@ enum {
  * can only be modified by current, we can reuse trace_recursion.
  */
 	TRACE_IRQ_BIT,
+
+	/* Set if the function is in the set_graph_function file */
+	TRACE_GRAPH_BIT,
+
+	/*
+	 * In the very unlikely case that an interrupt came in
+	 * at a start of graph tracing, and we want to trace
+	 * the function in that interrupt, the depth can be greater
+	 * than zero, because of the preempted start of a previous
+	 * trace. In an even more unlikely case, depth could be 2
+	 * if a softirq interrupted the start of graph tracing,
+	 * followed by an interrupt preempting a start of graph
+	 * tracing in the softirq, and depth can even be 3
+	 * if an NMI came in at the start of an interrupt function
+	 * that preempted a softirq start of a function that
+	 * preempted normal context!!!! Luckily, it can't be
+	 * greater than 3, so the next two bits are a mask
+	 * of what the depth is when we set TRACE_GRAPH_BIT
+	 */
+
+	TRACE_GRAPH_DEPTH_START_BIT,
+	TRACE_GRAPH_DEPTH_END_BIT,
 };
 
 #define trace_recursion_set(bit)	do { (current)->trace_recursion |= (1<<(bit)); } while (0)
 #define trace_recursion_clear(bit)	do { (current)->trace_recursion &= ~(1<<(bit)); } while (0)
 #define trace_recursion_test(bit)	((current)->trace_recursion & (1<<(bit)))
 
+#define trace_recursion_depth() \
+	(((current)->trace_recursion >> TRACE_GRAPH_DEPTH_START_BIT) & 3)
+#define trace_recursion_set_depth(depth) \
+	do {								\
+		current->trace_recursion &=				\
+			~(3 << TRACE_GRAPH_DEPTH_START_BIT);		\
+		current->trace_recursion |=				\
+			((depth) & 3) << TRACE_GRAPH_DEPTH_START_BIT;	\
+	} while (0)
+
 #define TRACE_CONTEXT_BITS	4
 
 #define TRACE_FTRACE_START	TRACE_FTRACE_BIT
@@ -843,8 +875,9 @@ extern void __trace_graph_return(struct trace_array *tr,
 extern struct ftrace_hash *ftrace_graph_hash;
 extern struct ftrace_hash *ftrace_graph_notrace_hash;
 
-static inline int ftrace_graph_addr(unsigned long addr)
+static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
 {
+	unsigned long addr = trace->func;
 	int ret = 0;
 
 	preempt_disable_notrace();
@@ -855,6 +888,14 @@ static inline int ftrace_graph_addr(unsigned long addr)
 	}
 
 	if (ftrace_lookup_ip(ftrace_graph_hash, addr)) {
+
+		/*
+		 * This needs to be cleared on the return functions
+		 * when the depth is zero.
+		 */
+		trace_recursion_set(TRACE_GRAPH_BIT);
+		trace_recursion_set_depth(trace->depth);
+
 		/*
 		 * If no irqs are to be traced, but a set_graph_function
 		 * is set, and called by an interrupt handler, we still
@@ -872,6 +913,13 @@ out:
 	return ret;
 }
 
+static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+{
+	if (trace_recursion_test(TRACE_GRAPH_BIT) &&
+	    trace->depth == trace_recursion_depth())
+		trace_recursion_clear(TRACE_GRAPH_BIT);
+}
+
 static inline int ftrace_graph_notrace_addr(unsigned long addr)
 {
 	int ret = 0;
@@ -885,7 +933,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
 	return ret;
 }
 #else
-static inline int ftrace_graph_addr(unsigned long addr)
+static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
 {
 	return 1;
 }
@@ -894,6 +942,8 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
 {
 	return 0;
 }
+static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+{ }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 extern unsigned int fgraph_max_depth;
@@ -901,7 +951,8 @@ extern unsigned int fgraph_max_depth;
 static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
 {
 	/* trace it when it is-nested-in or is a function enabled. */
-	return !(trace->depth || ftrace_graph_addr(trace->func)) ||
+	return !(trace_recursion_test(TRACE_GRAPH_BIT) ||
+		 ftrace_graph_addr(trace)) ||
 		(trace->depth < 0) ||
 		(fgraph_max_depth && trace->depth >= fgraph_max_depth);
 }
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 2561460d7baf..086af4f5c3e8 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -509,6 +509,8 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
 	int cpu;
 	int pc;
 
+	ftrace_graph_addr_finish(trace);
+
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = per_cpu_ptr(tr->trace_buffer.data, cpu);
@@ -532,6 +534,8 @@ void set_graph_array(struct trace_array *tr)
 
 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 {
+	ftrace_graph_addr_finish(trace);
+
 	if (tracing_thresh &&
 	    (trace->rettime - trace->calltime < tracing_thresh))
 		return;
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index b7357f9f82a3..98ea6d28df15 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -208,6 +208,8 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 	unsigned long flags;
 	int pc;
 
+	ftrace_graph_addr_finish(trace);
+
 	if (!func_prolog_dec(tr, &data, &flags))
 		return;
 
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index a86b303e6c67..7d04b9890755 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -270,6 +270,8 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace)
 	unsigned long flags;
 	int pc;
 
+	ftrace_graph_addr_finish(trace);
+
 	if (!func_prolog_preempt_disable(tr, &data, &pc))
 		return;