1.0.24.26: fix release spinlock

[sbcl.git] / src / runtime / x86-arch.h

diff --git a/src/runtime/x86-arch.h b/src/runtime/x86-arch.h
index 1a51e6b..2dfac47 100644 (file)
--- a/src/runtime/x86-arch.h
+++ b/src/runtime/x86-arch.h
@@ -48,12 +48,6 @@ get_spinlock(volatile lispobj *word, unsigned long value)
 #endif
 }
 
-static inline void
-release_spinlock(volatile lispobj *word)
-{
-    *word=0;
-}
-
 #include <stdio.h>
 
 static inline lispobj
@@ -74,6 +68,14 @@ swap_lispobjs(volatile lispobj *dest, lispobj value)
     return old_value;
 }
 
+static inline void
+release_spinlock(volatile lispobj *word)
+{
+    /* A memory barrier is needed, use swap_lispobjs. See comment in
+     * RELEASE-SPINLOCK in target-thread.lisp. */
+    swap_lispobjs(word,0);
+}
+
 extern void fast_bzero_detect(void *, size_t);
 extern void (*fast_bzero_pointer)(void *, size_t);