Fix deadlocks in GC on Windows.

[sbcl.git] / src / assembly / x86-64 / alloc.lisp

diff --git a/src/assembly/x86-64/alloc.lisp b/src/assembly/x86-64/alloc.lisp
index 68a8ce3..e40d380 100644 (file)
--- a/src/assembly/x86-64/alloc.lisp
+++ b/src/assembly/x86-64/alloc.lisp
@@ -92,27 +92,33 @@
                (inst push other)
                (inst push target)
                (emit-label get-tls-index-lock)
-               (inst mov target 1)
-               (zeroize rax-tn)
-               (inst lock)
-               (inst cmpxchg (make-ea-for-symbol-value *tls-index-lock*) target)
-               (inst jmp :ne get-tls-index-lock)
+               (let ((not-rax ,(if (eql 'rax reg) 'other 'target)))
+                 (inst mov not-rax 1)
+                 (zeroize rax-tn)
+                 (inst cmpxchg (make-ea-for-symbol-value *tls-index-lock*)
+                       not-rax :lock)
+                 (inst jmp :ne get-tls-index-lock))
                ;; The symbol is now in OTHER.
                (inst pop other)
                ;; Now with the lock held, see if the symbol's tls index has been
                ;; set in the meantime.
                (loadw target other symbol-tls-index-slot other-pointer-lowtag)
-               (inst or target target)
+               (inst test target target)
                (inst jmp :ne release-tls-index-lock)
                ;; Allocate a new tls-index.
                (load-symbol-value target *free-tls-index*)
-               (let ((error (generate-error-code nil 'tls-exhausted-error)))
-                 (inst cmp target (fixnumize tls-size))
-                 (inst jmp :ge error))
+               (let ((not-error (gen-label))
+                     (error (generate-error-code nil 'tls-exhausted-error)))
+                 (inst cmp target (ash tls-size word-shift))
+                 (inst jmp :l not-error)
+                 (%clear-pseudo-atomic)
+                 (inst jmp error)
+                 (emit-label not-error))
                (inst add (make-ea-for-symbol-value *free-tls-index*)
-                     (fixnumize 1))
+                     n-word-bytes)
                (storew target other symbol-tls-index-slot other-pointer-lowtag)
                (emit-label release-tls-index-lock)
+               ;; No need for barriers on x86/x86-64 on unlock.
                (store-symbol-value 0 *tls-index-lock*)
                ;; Restore OTHER.
                (inst pop other))