tracing/function-return-tracer: free the return stack on free_task()

Impact: avoid losing some traces when a task is freed

do_exit() is not the last function called when a task finishes.
There are still some functions which are to be called such as
ree_task().  So we delay the freeing of the return stack to the
last moment.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/exit.c b/kernel/exit.c
index ef04d03..e5ae36e 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -47,7 +47,6 @@
 #include <linux/task_io_accounting_ops.h>
 #include <linux/tracehook.h>
 #include <trace/sched.h>
-#include <linux/ftrace.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -1128,7 +1127,6 @@ NORET_TYPE void do_exit(long code)
        preempt_disable();
        /* causes final put_task_struct in finish_task_switch(). */
        tsk->state = TASK_DEAD;
-       ftrace_retfunc_exit_task(tsk);
        schedule();
        BUG();
        /* Avoid "noreturn function does return".  */

diff --git a/kernel/fork.c b/kernel/fork.c
index fbf4a4c..d6e1a32 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -140,6 +140,7 @@ void free_task(struct task_struct *tsk)
        prop_local_destroy_single(&tsk->dirties);
        free_thread_info(tsk->stack);
        rt_mutex_debug_task_free(tsk);
+       ftrace_retfunc_exit_task(tsk);
        free_task_struct(tsk);
 }
 EXPORT_SYMBOL(free_task);