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>

2 files changed, 1 insertions, 2 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index ef04d03b3286..e5ae36ebe8af 100644
--- 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 fbf4a4c0a628..d6e1a3205f62 100644
--- 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);