teach IR1-TRANSFORM-TYPE-PREDICATE about alien types

[sbcl.git] / src / code / target-thread.lisp

diff --git a/src/code/target-thread.lisp b/src/code/target-thread.lisp
index 7ec3309..080c173 100644 (file)
--- a/src/code/target-thread.lisp
+++ b/src/code/target-thread.lisp
@@ -78,10 +78,16 @@ read by the function THREAD-ERROR-THREAD."))
   ((cycle :initarg :cycle :reader thread-deadlock-cycle))
   (:report
    (lambda (condition stream)
-     (let ((*print-circle* t))
-       (format stream "Deadlock cycle detected:~%~@<   ~@;~
-                     ~{~:@_~S~:@_~}~:@>"
-               (mapcar #'car (thread-deadlock-cycle condition)))))))
+     (let* ((*print-circle* t)
+            (cycle (thread-deadlock-cycle condition))
+            (start (caar cycle)))
+       (format stream "Deadlock cycle detected:~%")
+       (loop for part = (pop cycle)
+             while part
+             do (format stream "    ~S~%  waited for:~%    ~S~%  owned by:~%"
+                        (car part)
+                        (cdr part)))
+       (format stream "    ~S~%" start)))))
 
 #!+sb-doc
 (setf
@@ -362,6 +368,8 @@ HOLDING-MUTEX-P."
   ;; 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 ()
@@ -373,18 +381,21 @@ HOLDING-MUTEX-P."
                (let ((other-thread (mutex-%owner lock)))
                  (cond ((not other-thread))
                        ((eq self other-thread)
-                        (let* ((chain (deadlock-chain self origin))
-                               (barf
-                                (format nil
-                                        "~%WARNING: DEADLOCK CYCLE DETECTED:~%~@<   ~@;~
-                                         ~{~:@_~S~:@_~}~:@>~
-                                         ~%END OF CYCLE~%"
-                                        (mapcar #'car chain))))
-                          ;; Barf to stderr in case the system is too tied up
-                          ;; to report the error properly -- to avoid cross-talk
-                          ;; build the whole string up first.
-                          (write-string barf sb!sys:*stderr*)
-                          (finish-output sb!sys:*stderr*)
+                        (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)))))
                           (error 'thread-deadlock
                                  :thread *current-thread*
                                  :cycle chain)))
@@ -417,7 +428,7 @@ HOLDING-MUTEX-P."
                         (list (list thread lock)))
                        (t
                         (if other-lock
-                            (cons (list thread lock)
+                            (cons (cons thread lock)
                                   (deadlock-chain other-thread other-lock))
                             ;; Again, the deadlock is gone?
                             (return-from check-deadlock nil)))))))