do (sb!ext:spin-loop-hint))
do (thread-yield)))
,@body)
- ;; FIXME: SETF + write barrier should to be enough here.
- ;; ...but GET-CAS-EXPANSION doesn't return a WRITE-FORM.
- ;; ...maybe it should?
(unless (eq ,owner ,self)
(let ((,old ,self)
(,new nil))
;; Make sure to get the current value.
(sb!ext:compare-and-swap (mutex-%owner mutex) nil nil))
+(sb!ext:defglobal **deadlock-lock** nil)
+
;;; Signals an error if owner of LOCK is waiting on a lock whose release
;;; depends on the current thread. Does not detect deadlocks from sempahores.
(defun check-deadlock ()
(let ((other-thread (mutex-%owner lock)))
(cond ((not other-thread))
((eq self other-thread)
- (let* ((chain (deadlock-chain self origin))
+ (let* ((chain
+ (with-cas-lock ((symbol-value '**deadlock-lock**))
+ (prog1 (deadlock-chain self origin)
+ ;; We're now committed to signaling the
+ ;; error and breaking the deadlock, so
+ ;; mark us as no longer waiting on the
+ ;; lock. This ensures that a single
+ ;; deadlock is reported in only one
+ ;; thread, and that we don't look like
+ ;; we're waiting on the lock when print
+ ;; stuff -- because that may lead to
+ ;; further deadlock checking, in turn
+ ;; possibly leading to a bogus vicious
+ ;; metacycle on PRINT-OBJECT.
+ (setf (thread-waiting-for self) nil))))
(barf
- (format nil
- "~%WARNING: DEADLOCK CYCLE DETECTED:~%~@< ~@;~
- ~{~:@_~S~:@_~}~:@>~
- ~%END OF CYCLE~%"
- (mapcar #'car chain))))
+ (with-output-to-string (s)
+ (funcall (formatter
+ "~%WARNING: DEADLOCK CYCLE DETECTED:~%~@< ~@;~
+ ~{~:@_~S~:@_~}~:@>~
+ ~%END OF CYCLE~%")
+ s
+ (mapcar #'car chain)))))
;; Barf to stderr in case the system is too tied up
- ;; to report the error properly -- to avoid cross-talk
+ ;; to report the error properly -- and to avoid cross-talk
;; build the whole string up first.
+ ;;
+ ;; ...would be even better if we had
+ ;; sensible locks on streams, but what can
+ ;; you do...
(write-string barf sb!sys:*stderr*)
(finish-output sb!sys:*stderr*)
(error 'thread-deadlock
#!-sb-thread
(when old
(error "Strange deadlock on ~S in an unithreaded build?" mutex))
- #!-sb-futex
+ #!-(and sb-thread sb-futex)
(and (not old)
;; Don't even bother to try to CAS if it looks bad.
(not (sb!ext:compare-and-swap (mutex-%owner mutex) nil new-owner)))
- #!+sb-futex
+ #!+(and sb-thread sb-futex)
;; From the Mutex 2 algorithm from "Futexes are Tricky" by Ulrich Drepper.
(when (eql +lock-free+ (sb!ext:compare-and-swap (mutex-state mutex)
+lock-free+
;; FIXME: Is a :memory barrier too strong here? Can we use a :write
;; barrier instead?
(barrier (:memory)))
- #!+sb-futex
+ #!+(and sb-thread sb-futex)
(when old-owner
;; FIXME: once ATOMIC-INCF supports struct slots with word sized
;; unsigned-byte type this can be used:
#!+sb-doc
"Waitqueue type."
(name nil :type (or null thread-name))
- #!+sb-futex
+ #!+(and sb-thread sb-futex)
(token nil))
#!+(and sb-thread (not sb-futex))
(when (not (minusp new-count))
(setf (semaphore-%count semaphore) new-count)
(when notification
- (setf (semaphore-notifiction-%status notification) t))
+ (setf (semaphore-notification-%status notification) t))
;; FIXME: We don't actually document this -- should we just
;; return T, or document new count as the return?
new-count))))
(with-all-threads-lock
(loop
(if (thread-alive-p thread)
- (let* ((epoch sb!kernel::*gc-epoch*)
- (offset (sb!kernel:get-lisp-obj-address
+ (let* ((offset (sb!kernel:get-lisp-obj-address
(sb!vm::symbol-tls-index symbol)))
- (tl-val (sap-ref-word (%thread-sap thread) offset)))
+ (obj (sap-ref-lispobj (%thread-sap thread) offset))
+ (tl-val (sb!kernel:get-lisp-obj-address obj)))
(cond ((zerop offset)
(return (values nil :no-tls-value)))
((or (eql tl-val sb!vm:no-tls-value-marker-widetag)
(eql tl-val sb!vm:unbound-marker-widetag))
(return (values nil :unbound-in-thread)))
(t
- (multiple-value-bind (obj ok) (make-lisp-obj tl-val nil)
- ;; The value we constructed may be invalid if a GC has
- ;; occurred. That is harmless, though, since OBJ is
- ;; either in a register or on stack, and we are
- ;; conservative on both on GENCGC -- so a bogus object
- ;; is safe here as long as we don't return it. If we
- ;; ever port threads to a non-conservative GC we must
- ;; pin the TL-VAL address before constructing OBJ, or
- ;; make WITH-ALL-THREADS-LOCK imply WITHOUT-GCING.
- ;;
- ;; The reason we don't just rely on TL-VAL pinning the
- ;; object is that the call to MAKE-LISP-OBJ may cause
- ;; bignum allocation, at which point TL-VAL might not
- ;; be alive anymore -- hence the epoch check.
- (when (eq epoch sb!kernel::*gc-epoch*)
- (if ok
- (return (values obj :ok))
- (return (values obj :invalid-tls-value))))))))
+ (return (values obj :ok)))))
(return (values nil :thread-dead))))))
(defun %set-symbol-value-in-thread (symbol thread value)
(cond ((zerop offset)
(values nil :no-tls-value))
(t
- (setf (sap-ref-word (%thread-sap thread) offset)
- (get-lisp-obj-address value))
+ (setf (sap-ref-lispobj (%thread-sap thread) offset)
+ value)
(values value :ok))))
(values nil :thread-dead)))))
projects / sbcl.git / blobdiff