Fix broken link
Change-Id: I9808ad0cdc2c17519563ea97b09b23d8211ed7d2
diff --git a/aos/linux_code/ipc_lib/aos_sync.cc b/aos/linux_code/ipc_lib/aos_sync.cc
index b4b32ad..92eb1a1 100644
--- a/aos/linux_code/ipc_lib/aos_sync.cc
+++ b/aos/linux_code/ipc_lib/aos_sync.cc
@@ -33,7 +33,7 @@
using ::aos::linux_code::ipc_lib::FutexAccessorObserver;
-// This code was originally based on <http://www.akkadia.org/drepper/futex.pdf>,
+// This code was originally based on <https://www.akkadia.org/drepper/futex.pdf>,
// but is has since evolved a lot. However, that still has useful information.
//
// Finding information about actually using futexes is really REALLY hard, so