diff --git a/bitbake/lib/bb/data.py b/bitbake/lib/bb/data.py
index 198b628fad..50f2218a70 100644
--- a/bitbake/lib/bb/data.py
+++ b/bitbake/lib/bb/data.py
@@ -313,12 +313,10 @@ def generate_dependencies(d):
     shelldeps = set(key for key in keys if d.getVarFlag(key, "export") and not d.getVarFlag(key, "unexport"))
 
     deps = {}
-    taskdeps = {}
 
     tasklist = bb.data.getVar('__BBTASKS', d) or []
     for task in tasklist:
         deps[task] = build_dependencies(task, keys, shelldeps, d)
-
         newdeps = deps[task]
         seen = set()
         while newdeps:
@@ -330,9 +328,8 @@ def generate_dependencies(d):
                     deps[dep] = build_dependencies(dep, keys, shelldeps, d)
                 newdeps |=  deps[dep]
             newdeps -= seen
-        taskdeps[task] = seen | newdeps
         #print "For %s: %s" % (task, str(taskdeps[task]))
-    return taskdeps, deps
+    return tasklist, deps
 
 def inherits_class(klass, d):
     val = getVar('__inherit_cache', d) or []
diff --git a/bitbake/lib/bb/siggen.py b/bitbake/lib/bb/siggen.py
index 4dc09b3f9e..010c2cab26 100644
--- a/bitbake/lib/bb/siggen.py
+++ b/bitbake/lib/bb/siggen.py
@@ -57,7 +57,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
         self.runtaskdeps = {}
         self.gendeps = {}
         self.lookupcache = {}
-        self.basewhitelist = (data.getVar("BB_HASHBASE_WHITELIST", True) or "").split()
+        self.basewhitelist = set((data.getVar("BB_HASHBASE_WHITELIST", True) or "").split())
         self.taskwhitelist = data.getVar("BB_HASHTASK_WHITELIST", True) or None
 
         if self.taskwhitelist:
@@ -67,17 +67,31 @@ class SignatureGeneratorBasic(SignatureGenerator):
 
     def _build_data(self, fn, d):
 
-        taskdeps, gendeps = bb.data.generate_dependencies(d)
+        tasklist, gendeps = bb.data.generate_dependencies(d)
 
+        taskdeps = {}
         basehash = {}
         lookupcache = {}
 
-        for task in taskdeps:
+        for task in tasklist:
             data = d.getVar(task, False)
             lookupcache[task] = data
-            for dep in sorted(taskdeps[task]):
-                if dep in self.basewhitelist:
-                    continue
+
+            newdeps = gendeps[task]
+            seen = set()
+            while newdeps:
+                nextdeps = newdeps
+                seen |= nextdeps
+                newdeps = set()
+                for dep in nextdeps:
+                    if dep in self.basewhitelist:
+                        continue
+                    newdeps |= gendeps[dep]
+                newdeps -= seen
+
+            alldeps = seen - self.basewhitelist
+
+            for dep in sorted(alldeps):
                 if dep in lookupcache:
                     var = lookupcache[dep]
                 else:
@@ -88,6 +102,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
             if data is None:
                 bb.error("Task %s from %s seems to be empty?!" % (task, fn))
             self.basehash[fn + "." + task] = hashlib.md5(data).hexdigest()
+            taskdeps[task] = sorted(alldeps)
 
         self.taskdeps[fn] = taskdeps
         self.gendeps[fn] = gendeps