X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fsysmacs.lisp;h=b953cbcccfc3c678093f44e4f0774180c9d30b22;hb=8643c93d4db277f6e1cb880a42407ff29e19f618;hp=3556bc1c782440eeda9cf6da1af97b9da854a724;hpb=dcf8b8ccc1e15a5c1c6aba00204b7d3a81827acc;p=sbcl.git

diff --git a/src/code/sysmacs.lisp b/src/code/sysmacs.lisp
index 3556bc1..b953cbc 100644
--- a/src/code/sysmacs.lisp
+++ b/src/code/sysmacs.lisp
@@ -48,13 +48,30 @@ stopped for GC while T2 is waiting for the lock inside WITHOUT-GCING the
 system will be deadlocked. Since SBCL does not currently document its internal
 locks, application code can never be certain that this invariant is
 maintained."
-  `(unwind-protect
-        (without-interrupts
-          (let ((*gc-inhibit* t))
-            ,@body))
-     ;; the test is racy, but it can err only on the overeager side
-     (sb!kernel::maybe-handle-pending-gc)))
-
+  (with-unique-names (without-gcing-body)
+    `(flet ((,without-gcing-body ()
+              ,@body))
+       (if *gc-inhibit*
+           (,without-gcing-body)
+           (without-interrupts
+             ;; We need to disable interrupts before disabling GC, so that
+             ;; signal handlers using locks don't accidentally try to grab
+             ;; them with GC inhibited.
+             ;;
+             ;; It would be nice to implement this with just a single UWP, but
+             ;; unfortunately it seems that it cannot be done: the naive
+             ;; solution of binding both *INTERRUPTS-ENABLED* and
+             ;; *GC-INHIBIT*, and checking for both pending GC and interrupts
+             ;; in the cleanup breaks if we have a GC pending, but no
+             ;; interrupts, and we receive an asynch unwind while checking for
+             ;; the pending GC: we unwind before handling the pending GC, and
+             ;; will be left running with further GCs blocked due to the GC
+             ;; pending flag.
+             (unwind-protect
+                  (let ((*gc-inhibit* t))
+                    (,without-gcing-body))
+               (when (or *gc-pending* #!+sb-thread *stop-for-gc-pending*)
+                 (sb!unix::receive-pending-interrupt))))))))
 
 ;;; EOF-OR-LOSE is a useful macro that handles EOF.
 (defmacro eof-or-lose (stream eof-error-p eof-value)