Index: generic/tkEntry.c
==================================================================
--- generic/tkEntry.c
+++ generic/tkEntry.c
@@ -3291,21 +3291,25 @@
     char *p;
     Tcl_DString script;
 
     if (entryPtr->validateCmd == NULL ||
 	entryPtr->validate == VALIDATE_NONE) {
+        if (entryPtr->flags & VALIDATING) {
+            entryPtr->flags |= VALIDATE_ABORT;
+        }
 	return (varValidate ? TCL_ERROR : TCL_OK);
     }
 
     /*
-     * If we're already validating, then we're hitting a loop condition Return
-     * and set validate to 0 to disallow further validations and prevent
-     * current validation from finishing
+     * If we're already validating, then we're hitting a loop condition. Set
+     * validate to none to disallow further validations, arrange for flags
+     * to prevent current validation from finishing, and return.
      */
 
     if (entryPtr->flags & VALIDATING) {
 	entryPtr->validate = VALIDATE_NONE;
+        entryPtr->flags |= VALIDATE_ABORT;
 	return (varValidate ? TCL_ERROR : TCL_OK);
     }
 
     entryPtr->flags |= VALIDATING;
 

Index: tests/entry.test
==================================================================
--- tests/entry.test
+++ tests/entry.test
@@ -3356,11 +3356,11 @@
     .e configure -validatecommand [list doval2 %W %d %i %P %s %S %v %V]
     .e validate
     list [.e cget -validate] [.e get] $::vVals
 } -cleanup {
     destroy .e
-} -result {none mydata {.e -1 -1 nextdata nextdata {} all forced}}
+} -result {none nextdata {.e -1 -1 nextdata nextdata {} all forced}}
 
 ## This leaves validate alone because we trigger validation through the
 ## textvar (a write trace), and the write during validation triggers
 ## nothing (by definition of avoiding loops on var traces).  This is
 ## one of those "dangerous" conditions where the user will have a
@@ -3382,10 +3382,30 @@
     set ::e testdata
     list [.e cget -validate] [.e get] $::e $::vVals
 } -cleanup {
     destroy .e
 } -result {all testdata mydata {.e -1 -1 testdata mydata {} all forced}}
+
+## This leaves validate alone because we trigger validation through the
+## textvar (a write trace), and the write during validation triggers
+## nothing (by definition of avoiding loops on var traces).  This is
+## one of those "dangerous" conditions where the user will have a
+## different value in the entry widget shown as is in the textvar.
+test entry-19.21 {entry widget validation - bug 40e4bf6198} -setup {
+    unset -nocomplain ::e ::vVals
+} -body {
+    entry .e -validate key \
+        -validatecommand [list doval2 %W %d %i %P %s %S %v %V] \
+        -textvariable ::e
+    pack .e
+    set ::e origdata
+    .e insert 0 A
+    list [.e cget -validate] [.e get] $::e $::vVals
+} -cleanup {
+    destroy .e
+} -result {none origdata mydata {.e 1 0 Aorigdata origdata A key key}}
+
 ##
 ## End validation tests
 ##
 
 test entry-20.1 {widget deletion while active} -body {

Index: tests/spinbox.test
==================================================================
--- tests/spinbox.test
+++ tests/spinbox.test
@@ -3592,11 +3592,11 @@
     .e configure -validatecommand [list doval2 %W %d %i %P %s %S %v %V]
     .e validate
     list [.e cget -validate] [.e get] $::vVals
 } -cleanup {
     destroy .e
-} -result {none mydata {.e -1 -1 nextdata nextdata {} all forced}}
+} -result {none nextdata {.e -1 -1 nextdata nextdata {} all forced}}
 
 ## This leaves validate alone because we trigger validation through the
 ## textvar (a write trace), and the write during validation triggers
 ## nothing (by definition of avoiding loops on var traces).  This is
 ## one of those "dangerous" conditions where the user will have a
@@ -3618,10 +3618,30 @@
     set ::e testdata
     list [.e cget -validate] [.e get] $::e $::vVals
 } -cleanup {
     destroy .e
 } -result {all testdata mydata {.e -1 -1 testdata mydata {} all forced}}
+
+## This leaves validate alone because we trigger validation through the
+## textvar (a write trace), and the write during validation triggers
+## nothing (by definition of avoiding loops on var traces).  This is
+## one of those "dangerous" conditions where the user will have a
+## different value in the entry widget shown as is in the textvar.
+test spinbox-19.21 {spinbox widget validation - bug 40e4bf6198} -setup {
+    unset -nocomplain ::e ::vVals
+} -body {
+    spinbox .e -validate key \
+        -validatecommand [list doval2 %W %d %i %P %s %S %v %V] \
+        -textvariable ::e
+    pack .e
+    set ::e origdata
+    .e insert 0 A
+    list [.e cget -validate] [.e get] $::e $::vVals
+} -cleanup {
+    destroy .e
+} -result {none origdata mydata {.e 1 0 Aorigdata origdata A key key}}
+
 ##
 ## End validation tests
 ##
 
 test spinbox-20.1 {spinbox config, -format specifier} -body {