diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
index d57c183004..00a709ba44 100644
--- a/meta/classes/sstate.bbclass
+++ b/meta/classes/sstate.bbclass
@@ -40,7 +40,7 @@ python () {
         bb.data.setVar('SSTATE_SCAN_CMD', scan_cmd, d)
 
     namemap = []
-    for task in (bb.data.getVar('SSTATETASKS', d, True) or "").split():
+    for task in set((bb.data.getVar('SSTATETASKS', d, True) or "").split()):
         namemap.append(bb.data.getVarFlag(task, 'sstate-name', d))
         funcs = bb.data.getVarFlag(task, 'prefuncs', d) or ""
         funcs = "sstate_task_prefunc " + funcs
@@ -195,7 +195,7 @@ def sstate_clean_cachefile(ss, d):
     oe.path.remove(sstatepkgfile)
 
 def sstate_clean_cachefiles(d):
-    for task in (bb.data.getVar('SSTATETASKS', d, True) or "").split():
+    for task in set((bb.data.getVar('SSTATETASKS', d, True) or "").split()):
         ss = sstate_state_fromvars(d, task[3:])
         sstate_clean_cachefile(ss, d)