--- a/layout/svg/nsSVGImageFrame.cpp
+++ b/layout/svg/nsSVGImageFrame.cpp
@@ -464,20 +464,38 @@ nsSVGImageFrame::ReflowSVG()
                     "ReflowSVG mechanism not designed for this");
 
   if (!nsSVGUtils::NeedsReflowSVG(this)) {
     return;
   }
 
   gfxContext tmpCtx(gfxPlatform::GetPlatform()->ScreenReferenceSurface());
 
-  gfxMatrix identity;
-  GeneratePath(&tmpCtx, identity);
-
+  // We'd like to just pass the identity matrix to GeneratePath, but if
+  // this frame's user space size is _very_ large/small then the extents we
+  // obtain below might have overflowed or otherwise be broken. This would
+  // cause us to end up with a broken mRect and visual overflow rect and break
+  // painting of this frame. This is particularly noticeable if the transforms
+  // between us and our nsSVGOuterSVGFrame scale this frame to a reasonable
+  // size. To avoid this we sadly have to do extra work to account for the
+  // transforms between us and our nsSVGOuterSVGFrame, even though the
+  // overwhelming number of SVGs will never have this problem.
+  // XXX Will Azure eventually save us from having to do this?
+  gfxSize scaleFactors = GetCanvasTM(FOR_OUTERSVG_TM).ScaleFactors(true);
+  bool applyScaling = fabs(scaleFactors.width) >= 1e-6 &&
+                      fabs(scaleFactors.height) >= 1e-6;
+  gfxMatrix scaling;
+  if (applyScaling) {
+    scaling.Scale(scaleFactors.width, scaleFactors.height);
+  } 
+  GeneratePath(&tmpCtx, scaling);
   gfxRect extent = tmpCtx.GetUserPathExtent();
+  if (applyScaling) {
+    extent.Scale(1 / scaleFactors.width, 1 / scaleFactors.height);
+  }
 
   if (!extent.IsEmpty()) {
     mRect = nsLayoutUtils::RoundGfxRectToAppRect(extent, 
               PresContext()->AppUnitsPerCSSPixel());
   } else {
     mRect.SetEmpty();
   }
 

--- a/layout/svg/nsSVGPathGeometryFrame.cpp
+++ b/layout/svg/nsSVGPathGeometryFrame.cpp
@@ -304,17 +304,38 @@ nsSVGPathGeometryFrame::ReflowSVG()
   // stroke-opacity="0"). GetHitTestFlags() accounts for 'pointer-events'.
   uint16_t hitTestFlags = GetHitTestFlags();
   if ((hitTestFlags & SVG_HIT_TEST_FILL)) {
    flags |= nsSVGUtils::eBBoxIncludeFillGeometry;
   }
   if ((hitTestFlags & SVG_HIT_TEST_STROKE)) {
    flags |= nsSVGUtils::eBBoxIncludeStrokeGeometry;
   }
-  gfxRect extent = GetBBoxContribution(gfxMatrix(), flags);
+ 
+  // We'd like to just pass the identity matrix to GetBBoxContribution, but if
+  // this frame's user space size is _very_ large/small then the extents we
+  // obtain below might have overflowed or otherwise be broken. This would
+  // cause us to end up with a broken mRect and visual overflow rect and break
+  // painting of this frame. This is particularly noticeable if the transforms
+  // between us and our nsSVGOuterSVGFrame scale this frame to a reasonable
+  // size. To avoid this we sadly have to do extra work to account for the
+  // transforms between us and our nsSVGOuterSVGFrame, even though the
+  // overwhelming number of SVGs will never have this problem.
+  // XXX Will Azure eventually save us from having to do this?
+  gfxSize scaleFactors = GetCanvasTM(FOR_OUTERSVG_TM).ScaleFactors(true);
+  bool applyScaling = fabs(scaleFactors.width) >= 1e-6 &&
+                      fabs(scaleFactors.height) >= 1e-6;
+  gfxMatrix scaling;
+  if (applyScaling) {
+    scaling.Scale(scaleFactors.width, scaleFactors.height);
+  }
+  gfxRect extent = GetBBoxContribution(scaling, flags);
+  if (applyScaling) {
+    extent.Scale(1 / scaleFactors.width, 1 / scaleFactors.height);
+  }
   mRect = nsLayoutUtils::RoundGfxRectToAppRect(extent,
             PresContext()->AppUnitsPerCSSPixel());
 
   if (mState & NS_FRAME_FIRST_REFLOW) {
     // Make sure we have our filter property (if any) before calling
     // FinishAndStoreOverflow (subsequent filter changes are handled off
     // nsChangeHint_UpdateEffects):
     nsSVGEffects::UpdateEffects(this);