[PATCH bpf] rethook: Fix to use WRITE_ONCE() for rethook::handler

[Masami Hiramatsu <mhiramat@xxxxxxxxxx>]

Since the function pointered by rethook::handler never be removed when
the rethook is alive, it doesn't need to use rcu_assign_pointer() to
update it. Just use WRITE_ONCE().

Reported-by: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 kernel/trace/rethook.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
index ab463a4d2b23..b56833700d23 100644
--- a/kernel/trace/rethook.c
+++ b/kernel/trace/rethook.c
@@ -65,7 +65,7 @@ static void rethook_free_rcu(struct rcu_head *head)
  */
 void rethook_free(struct rethook *rh)
 {
-	rcu_assign_pointer(rh->handler, NULL);
+	WRITE_ONCE(rh->handler, NULL);
 
 	call_rcu(&rh->rcu, rethook_free_rcu);
 }