Update for nightly-2018-08-18

1 files changed, 3 insertions, 2 deletions

diff --git a/ctr-std/src/sys_common/thread_local.rs b/ctr-std/src/sys_common/thread_local.rs
index d0d6224..bb72cb0 100644
--- a/ctr-std/src/sys_common/thread_local.rs
+++ b/ctr-std/src/sys_common/thread_local.rs
@@ -161,14 +161,15 @@ impl StaticKey {
         // Additionally a 0-index of a tls key hasn't been seen on windows, so
         // we just simplify the whole branch.
         if imp::requires_synchronized_create() {
+            // We never call `INIT_LOCK.init()`, so it is UB to attempt to
+            // acquire this mutex reentrantly!
             static INIT_LOCK: Mutex = Mutex::new();
-            INIT_LOCK.lock();
+            let _guard = INIT_LOCK.lock();
             let mut key = self.key.load(Ordering::SeqCst);
             if key == 0 {
                 key = imp::create(self.dtor) as usize;
                 self.key.store(key, Ordering::SeqCst);
             }
-            INIT_LOCK.unlock();
             rtassert!(key != 0);
             return key
         }