X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fdebug-int.lisp;h=d5dd4c7ede485f2fac6ebb80c51681dae10bad64;hb=6ddc6bb305b4f218780d4b2c9a2ac3584a85f94a;hp=7411bc59a10f25a2997d59c9e1a2bde051de75f5;hpb=cdd026dddac3eaddbaa0221503e49e2673d54545;p=sbcl.git

diff --git a/src/code/debug-int.lisp b/src/code/debug-int.lisp
index 7411bc5..d5dd4c7 100644
--- a/src/code/debug-int.lisp
+++ b/src/code/debug-int.lisp
@@ -539,8 +539,7 @@
 (sb!alien:define-alien-routine component-ptr-from-pc (system-area-pointer)
   (pc system-area-pointer))
 
-#!+gencgc (declaim (inline valid-lisp-pointer-p))
-#!+gencgc
+(declaim (inline valid-lisp-pointer-p))
 (sb!alien:define-alien-routine valid-lisp-pointer-p sb!alien:int
   (pointer system-area-pointer))
 
@@ -1974,6 +1973,18 @@ register."
 ;;; (Such values can arise in registers on machines with conservative
 ;;; GC, and might also arise in debug variable locations when
 ;;; those variables are invalid.)
+;;;
+;;; NOTE: this function is not GC-safe in the slightest when creating
+;;; a pointer to an object in dynamic space.  If a GC occurs between
+;;; the start of the call to VALID-LISP-POINTER-P and the end of
+;;; %MAKE-LISP-OBJ then the object could move before the boxed pointer
+;;; is constructed.  This can happen on CHENEYGC if an asynchronous
+;;; interrupt occurs within the window.  This can happen on GENCGC
+;;; under the same circumstances, but is more likely due to all GENCGC
+;;; platforms supporting threaded operation.  This is somewhat
+;;; mitigated on x86oids due to the conservative stack and interrupt
+;;; context "scavenging" on such platforms, but there still may be a
+;;; vulnerable window.
 (defun make-lisp-obj (val &optional (errorp t))
   (if (or
        ;; fixnum
@@ -1987,21 +1998,7 @@ register."
        ;; unbound marker
        (= val sb!vm:unbound-marker-widetag)
        ;; pointer
-       #!+gencgc
-       (not (zerop (valid-lisp-pointer-p (int-sap val))))
-       ;; FIXME: There is no fundamental reason not to use the above
-       ;; function on other platforms as well, but I didn't have
-       ;; others available while doing this. --NS 2007-06-21
-       #!-gencgc
-       (and (logbitp 0 val)
-            (or (< sb!vm:read-only-space-start val
-                   (ash sb!vm:*read-only-space-free-pointer*
-                        sb!vm:n-fixnum-tag-bits))
-                (< sb!vm:static-space-start val
-                   (ash sb!vm:*static-space-free-pointer*
-                        sb!vm:n-fixnum-tag-bits))
-                (< (current-dynamic-space-start) val
-                   (sap-int (dynamic-space-free-pointer))))))
+       (not (zerop (valid-lisp-pointer-p (int-sap val)))))
       (values (%make-lisp-obj val) t)
       (if errorp
           (error "~S is not a valid argument to ~S"