cs & threads: another spurious-CAS-failure accomodation

2020-06-29 10:11:10 -06:00 · 2020-06-29 10:11:10 -06:00 · 1118705bef
commit 1118705bef
parent f38ffc53ed
1 changed files with 7 additions and 3 deletions
--- a/racket/src/thread/future-lock.rkt
+++ b/racket/src/thread/future-lock.rkt
@ -57,6 +57,10 @@
      (loop))))

 (define (lock-release lock)
-  (unless (box-cas! lock 1 0)
-    (internal-error "lock release failed!"))
-  (end-future-uninterrupted))
+  (cond
+    [(box-cas! lock 1 0)
+     (end-future-uninterrupted)]
+    [(eq? (unbox lock) 0)
+     ;; not just a spurious failure...
+     (internal-error "lock release failed!")]
+    [else (lock-release lock)]))