--- kernel/trace/ftrace.c

+++ kernel/trace/ftrace.c

@@ -3172,7 +3172,7 @@ static int start_graph_tracing(void)

/* The cpu_boot init_task->ret_stack will never be freed */

for_each_online_cpu(cpu) {

if (!idle_task(cpu)->ret_stack)

- ftrace_graph_init_idle_task(idle_task(cpu), cpu);

+ ftrace_graph_init_task(idle_task(cpu));

}

do {

@@ -3262,49 +3262,6 @@ void unregister_ftrace_graph(void)

mutex_unlock(&ftrace_lock);

}

-static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);

-

-static void

-graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)

-{

- atomic_set(&t->tracing_graph_pause, 0);

- atomic_set(&t->trace_overrun, 0);

- t->ftrace_timestamp = 0;

- /* make curr_ret_stack visable before we add the ret_stack */

- smp_wmb();

- t->ret_stack = ret_stack;

-}

-

-/*

- * Allocate a return stack for the idle task. May be the first

- * time through, or it may be done by CPU hotplug online.

- */

-void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)

-{

- t->curr_ret_stack = -1;

- /*

- * The idle task has no parent, it either has its own

- * stack or no stack at all.

- */

- if (t->ret_stack)

- WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));

-

- if (ftrace_graph_active) {

- struct ftrace_ret_stack *ret_stack;

-

- ret_stack = per_cpu(idle_ret_stack, cpu);

- if (!ret_stack) {

- ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH

- * sizeof(struct ftrace_ret_stack),

- GFP_KERNEL);

- if (!ret_stack)

- return;

- per_cpu(idle_ret_stack, cpu) = ret_stack;

- }

- graph_init_task(t, ret_stack);

- }

-}

-

/* Allocate a return stack for newly created task */

void ftrace_graph_init_task(struct task_struct *t)

{

@@ -3320,7 +3277,12 @@ void ftrace_graph_init_task(struct task_

GFP_KERNEL);

if (!ret_stack)

return;

- graph_init_task(t, ret_stack);

+ atomic_set(&t->tracing_graph_pause, 0);

+ atomic_set(&t->trace_overrun, 0);

+ t->ftrace_timestamp = 0;

+ /* make curr_ret_stack visable before we add the ret_stack */

+ smp_wmb();

+ t->ret_stack = ret_stack;

}

}