diff --git a/layout/painting/nsDisplayList.cpp b/layout/painting/nsDisplayList.cpp
index 03d5eeea80a1..39076e262864 100644
--- a/layout/painting/nsDisplayList.cpp
+++ b/layout/painting/nsDisplayList.cpp
@@ -7351,9 +7351,11 @@ bool nsDisplayMask::ShouldPaintOnMaskLayer(LayerManager* aManager)
   nsSVGUtils::MaskUsage maskUsage;
   nsSVGUtils::DetermineMaskUsage(mFrame, mHandleOpacity, maskUsage);
 
+  // XXX Bug 1323912. nsSVGIntegrationUtils::PaintMask can not handle opacity
+  // correctly. Turn it off before bug fixed.
   // XXX Temporary disable paint clip-path onto mask before figure out
   // performance regression(bug 1325550).
-  if (maskUsage.shouldApplyClipPath) {
+  if (maskUsage.opacity != 1.0 || maskUsage.shouldApplyClipPath) {
     return false;
   }
 
diff --git a/layout/svg/nsSVGIntegrationUtils.cpp b/layout/svg/nsSVGIntegrationUtils.cpp
index 3e8309f2aa14..a19f72de70fe 100644
--- a/layout/svg/nsSVGIntegrationUtils.cpp
+++ b/layout/svg/nsSVGIntegrationUtils.cpp
@@ -725,25 +725,6 @@ nsSVGIntegrationUtils::IsMaskResourceReady(nsIFrame* aFrame)
   return true;
 }
 
-class AutoPopGroup
-{
-public:
-  AutoPopGroup() : mContext(nullptr) { }
-
-  ~AutoPopGroup() {
-    if (mContext) {
-      mContext->PopGroupAndBlend();
-    }
-  }
-
-  void SetContext(gfxContext* aContext) {
-    mContext = aContext;
-  }
-
-private:
-  gfxContext* mContext;
-};
-
 DrawResult
 nsSVGIntegrationUtils::PaintMask(const PaintFramesParams& aParams)
 {
@@ -756,6 +737,10 @@ nsSVGIntegrationUtils::PaintMask(const PaintFramesParams& aParams)
     return DrawResult::SUCCESS;
   }
 
+  // XXX Bug 1323912.
+  MOZ_ASSERT(maskUsage.opacity == 1.0,
+             "nsSVGIntegrationUtils::PaintMask can not handle opacity now.");
+
   gfxContext& ctx = aParams.ctx;
   nsIFrame* firstFrame =
     nsLayoutUtils::FirstContinuationOrIBSplitSibling(frame);
@@ -777,15 +762,6 @@ nsSVGIntegrationUtils::PaintMask(const PaintFramesParams& aParams)
                                                      SurfaceFormat::A8);
   }
 
-  nsTArray<nsSVGMaskFrame *> maskFrames = effectProperties.GetMaskFrames();
-  AutoPopGroup autoPop;
-  bool shouldPushOpacity = (maskUsage.opacity != 1.0) &&
-                           (maskFrames.Length() != 1);
-  if (shouldPushOpacity) {
-    ctx.PushGroupForBlendBack(gfxContentType::COLOR_ALPHA, maskUsage.opacity);
-    autoPop.SetContext(&ctx);
-  }
-
   gfxContextMatrixAutoSaveRestore matSR;
   nsPoint offsetToBoundingBox;
   nsPoint offsetToUserSpace;
@@ -817,8 +793,9 @@ nsSVGIntegrationUtils::PaintMask(const PaintFramesParams& aParams)
 
     SetupContextMatrix(frame, aParams, offsetToBoundingBox,
                        offsetToUserSpace);
-    result = PaintMaskSurface(aParams, maskTarget,
-                              shouldPushOpacity ?  1.0 : maskUsage.opacity,
+    nsTArray<nsSVGMaskFrame *> maskFrames = effectProperties.GetMaskFrames();
+
+    result = PaintMaskSurface(aParams, maskTarget, 1.0,
                               firstFrame->StyleContext(), maskFrames,
                               ctx.CurrentMatrix(), offsetToUserSpace);
     if (result != DrawResult::SUCCESS) {