return -EBUSY;
}
- /*
- * The curr_ret_stack is an index to ftrace return stack of
- * current task. Its value should be in [0, FTRACE_RETFUNC_
- * DEPTH) when the function graph tracer is used. To support
- * filtering out specific functions, it makes the index
- * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
- * so when it sees a negative index the ftrace will ignore
- * the record. And the index gets recovered when returning
- * from the filtered function by adding the FTRACE_NOTRACE_
- * DEPTH and then it'll continue to record functions normally.
- *
- * The curr_ret_stack is initialized to -1 and get increased
- * in this function. So it can be less than -1 only if it was
- * filtered out via ftrace_graph_notrace_addr() which can be
- * set from set_graph_notrace file in tracefs by user.
- */
- if (current->curr_ret_stack < -1)
- return -EBUSY;
-
calltime = trace_clock_local();
index = ++current->curr_ret_stack;
- if (ftrace_graph_notrace_addr(func))
- current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
barrier();
current->ret_stack[index].ret = ret;
current->ret_stack[index].func = func;
TRACE_GRAPH_DEPTH_START_BIT,
TRACE_GRAPH_DEPTH_END_BIT,
+
+ /*
+ * To implement set_graph_notrace, if this bit is set, we ignore
+ * function graph tracing of called functions, until the return
+ * function is called to clear it.
+ */
+ TRACE_GRAPH_NOTRACE_BIT,
};
#define trace_recursion_set(bit) do { (current)->trace_recursion |= (1<<(bit)); } while (0)
int cpu;
int pc;
+ if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
+ return 0;
+
+ if (ftrace_graph_notrace_addr(trace->func)) {
+ trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
+ /*
+ * Need to return 1 to have the return called
+ * that will clear the NOTRACE bit.
+ */
+ return 1;
+ }
+
if (!ftrace_trace_task(tr))
return 0;
ftrace_graph_addr_finish(trace);
+ if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+ trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+ return;
+ }
+
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
{
ftrace_graph_addr_finish(trace);
+ if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+ trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+ return;
+ }
+
if (tracing_thresh &&
(trace->rettime - trace->calltime < tracing_thresh))
return;