rethook: Fix to use WRITE_ONCE() for rethook:: Handler

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@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164868907688.21983.1606862921419988152.stgit@devnote2

diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
index ab463a4d2b2359660c8d725287e642e8f8ec1943..b56833700d23fb515a1b0e7a1f9a53e2e66d82c9 100644 (file)
--- 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);
 }