Fix bug [57945b574a6df0332efc4ac96b066f7c347b28f7|57945b574a]: lock in forking process under heavy multithreading. Thanks to Joe Mistachkin for the implementation of the fix, and Gustaf Neumann for the original report and testing the fix.

2 files changed, 40 insertions, 0 deletions

diff --git a/generic/tclInt.h b/generic/tclInt.h
index 356d250..54ecc0b 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -3059,6 +3059,9 @@ MODULE_SCOPE void	TclpInitUnlock(void);
 MODULE_SCOPE Tcl_Obj *	TclpObjListVolumes(void);
 MODULE_SCOPE void	TclpMasterLock(void);
 MODULE_SCOPE void	TclpMasterUnlock(void);
+MODULE_SCOPE void	TclpMutexLock(void);
+MODULE_SCOPE void	TclpMutexUnlock(void);
+MODULE_SCOPE void	TclMutexUnlockAndFinalize(Tcl_Mutex *mutex);
 MODULE_SCOPE int	TclpMatchFiles(Tcl_Interp *interp, char *separators,
 			    Tcl_DString *dirPtr, char *pattern, char *tail);
 MODULE_SCOPE int	TclpObjNormalizePath(Tcl_Interp *interp,
diff --git a/generic/tclThread.c b/generic/tclThread.c
index 198fa6a..c2112b7 100644
--- a/generic/tclThread.c
+++ b/generic/tclThread.c
@@ -284,6 +284,43 @@ Tcl_MutexFinalize(
 /*
  *----------------------------------------------------------------------
  *
+ * TclMutexUnlockAndFinalize --
+ *
+ *	This procedure is invoked to unlock and then finalize a mutex.
+ *	The mutex must have been locked by Tcl_MutexLock.  It is also
+ *	removed from the list of remembered objects.  The mutex can no
+ *	longer be used after calling this procedure.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Remove the mutex from the list.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclMutexUnlockAndFinalize(
+    Tcl_Mutex *mutexPtr)
+{
+    Tcl_Mutex mutex;
+    TclpMasterLock();
+    TclpMutexLock();
+#ifdef TCL_THREADS
+    mutex = *mutexPtr;
+    *mutexPtr = NULL; /* Force it to be created again. */
+    Tcl_MutexUnlock(&mutex);
+    TclpFinalizeMutex(&mutex);
+#endif
+    ForgetSyncObject(mutexPtr, &mutexRecord);
+    TclpMutexUnlock();
+    TclpMasterUnlock();
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * TclRememberCondition
  *
  *	Keep a list of condition variables used during finalization.