diff --git a/composite/compalloc.c b/composite/compalloc.c
index a3eb592bd..4a6107c0c 100644
--- a/composite/compalloc.c
+++ b/composite/compalloc.c
@@ -138,7 +138,6 @@ compRedirectWindow(ClientPtr pClient, WindowPtr pWin, int update)
     BUG_RETURN_VAL(!pClient, BadMatch);
 
     CompWindowPtr cw = GetCompWindow(pWin);
-    CompClientWindowPtr ccw;
     CompScreenPtr cs = GetCompScreen(pWin->drawable.pScreen);
     WindowPtr pLayerWin;
     Bool anyMarked = FALSE;
@@ -155,7 +154,7 @@ compRedirectWindow(ClientPtr pClient, WindowPtr pWin, int update)
      * Only one Manual update is allowed
      */
     if (cw && update == CompositeRedirectManual)
-        for (ccw = cw->clients; ccw; ccw = ccw->next)
+        for (CompClientWindowPtr ccw = cw->clients; ccw; ccw = ccw->next)
             if (ccw->update == CompositeRedirectManual)
                 return BadAccess;
 
@@ -164,7 +163,7 @@ compRedirectWindow(ClientPtr pClient, WindowPtr pWin, int update)
      * The client *could* allocate multiple, but while supported,
      * it is not expected to be common
      */
-    ccw = malloc(sizeof(CompClientWindowRec));
+    CompClientWindowPtr ccw = calloc(1, sizeof(CompClientWindowRec));
     if (!ccw)
         return BadAlloc;
     ccw->id = FakeClientID(pClient->index);
@@ -173,7 +172,7 @@ compRedirectWindow(ClientPtr pClient, WindowPtr pWin, int update)
      * Now make sure there's a per-window structure to hang this from
      */
     if (!cw) {
-        cw = malloc(sizeof(CompWindowRec));
+        cw = calloc(1, sizeof(CompWindowRec));
         if (!cw) {
             free(ccw);
             return BadAlloc;
@@ -348,14 +347,13 @@ int
 compRedirectSubwindows(ClientPtr pClient, WindowPtr pWin, int update)
 {
     CompSubwindowsPtr csw = GetCompSubwindows(pWin);
-    CompClientWindowPtr ccw;
     WindowPtr pChild;
 
     /*
      * Only one Manual update is allowed
      */
     if (csw && update == CompositeRedirectManual)
-        for (ccw = csw->clients; ccw; ccw = ccw->next)
+        for (CompClientWindowPtr ccw = csw->clients; ccw; ccw = ccw->next)
             if (ccw->update == CompositeRedirectManual)
                 return BadAccess;
     /*
@@ -363,7 +361,7 @@ compRedirectSubwindows(ClientPtr pClient, WindowPtr pWin, int update)
      * The client *could* allocate multiple, but while supported,
      * it is not expected to be common
      */
-    ccw = malloc(sizeof(CompClientWindowRec));
+    CompClientWindowPtr ccw = calloc(1, sizeof(CompClientWindowRec));
     if (!ccw)
         return BadAlloc;
     ccw->id = FakeClientID(pClient->index);
@@ -372,7 +370,7 @@ compRedirectSubwindows(ClientPtr pClient, WindowPtr pWin, int update)
      * Now make sure there's a per-window structure to hang this from
      */
     if (!csw) {
-        csw = malloc(sizeof(CompSubwindowsRec));
+        csw = calloc(1, sizeof(CompSubwindowsRec));
         if (!csw) {
             free(ccw);
             return BadAlloc;
diff --git a/composite/compext.c b/composite/compext.c
index 51ff41abb..fa4719ca7 100644
--- a/composite/compext.c
+++ b/composite/compext.c
@@ -700,7 +700,7 @@ PanoramiXCompositeNameWindowPixmap(ClientPtr client)
 
     LEGAL_NEW_RESOURCE(stuff->pixmap, client);
 
-    if (!(newPix = malloc(sizeof(PanoramiXRes))))
+    if (!(newPix = calloc(1, sizeof(PanoramiXRes))))
         return BadAlloc;
 
     newPix->type = XRT_PIXMAP;
@@ -769,7 +769,7 @@ PanoramiXCompositeGetOverlayWindow(ClientPtr client)
 
     cs = GetCompScreen(screenInfo.screens[0]);
     if (!cs->pOverlayWin) {
-        if (!(overlayWin = malloc(sizeof(PanoramiXRes))))
+        if (!(overlayWin = calloc(1, sizeof(PanoramiXRes))))
             return BadAlloc;
 
         overlayWin->type = XRT_WINDOW;
diff --git a/composite/compinit.c b/composite/compinit.c
index f75a0a514..c1d57e220 100644
--- a/composite/compinit.c
+++ b/composite/compinit.c
@@ -331,8 +331,6 @@ compAddAlternateVisuals(ScreenPtr pScreen, CompScreenPtr cs)
 Bool
 compScreenInit(ScreenPtr pScreen)
 {
-    CompScreenPtr cs;
-
     if (!dixRegisterPrivateKey(&CompScreenPrivateKeyRec, PRIVATE_SCREEN, 0))
         return FALSE;
     if (!dixRegisterPrivateKey(&CompWindowPrivateKeyRec, PRIVATE_WINDOW, 0))
@@ -342,7 +340,7 @@ compScreenInit(ScreenPtr pScreen)
 
     if (GetCompScreen(pScreen))
         return TRUE;
-    cs = (CompScreenPtr) malloc(sizeof(CompScreenRec));
+    CompScreenPtr cs = calloc(1, sizeof(CompScreenRec));
     if (!cs)
         return FALSE;
 
diff --git a/composite/compoverlay.c b/composite/compoverlay.c
index ffff34b7b..e2c4c58bf 100644
--- a/composite/compoverlay.c
+++ b/composite/compoverlay.c
@@ -96,9 +96,7 @@ CompOverlayClientPtr
 compCreateOverlayClient(ScreenPtr pScreen, ClientPtr pClient)
 {
     CompScreenPtr cs = GetCompScreen(pScreen);
-    CompOverlayClientPtr pOc;
-
-    pOc = (CompOverlayClientPtr) malloc(sizeof(CompOverlayClientRec));
+    CompOverlayClientPtr pOc = calloc(1, sizeof(CompOverlayClientRec));
     if (pOc == NULL)
         return NULL;