[PATCH 6/7] module: add two missing synchronize_sched()

[Cong Wang <xiyou.wangcong@gmail.com>]

In RCU doc, it said synchronize_sched() is used to mark the end
of update, so two synchronize_sched() are missing after
module list add/del.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 kernel/module.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 06e7dc5..2e7a5c5 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1775,6 +1775,7 @@ static void free_module(struct module *mod)
 	mutex_lock(&module_mutex);
 	stop_machine(__unlink_module, mod, NULL);
 	mutex_unlock(&module_mutex);
+	synchronize_sched();
 	mod_sysfs_teardown(mod);
 
 	/* Remove dynamic debug info */
@@ -2928,6 +2929,7 @@ static struct module *load_module(void __user *umod,
 	module_bug_finalize(info.hdr, info.sechdrs, mod);
 	list_add_rcu(&mod->list, &modules);
 	mutex_unlock(&module_mutex);
+	synchronize_sched();
 
 	/* Module is ready to execute: parsing args may do that. */
 	err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp, NULL);
-- 
1.7.7.6