threading issue with identifying grayscale (ImageMagick/ImageMagick#7152

)

coders/jpeg.c

@@ -2326,9 +2326,7 @@ static MagickBooleanType WriteJPEGImage_(const ImageInfo *image_info,
     *q;
 
   ssize_t
-    i;
-
-  ssize_t
+    i,
     y;
 
   struct jpeg_error_mgr

magick/attribute.c

@@ -980,6 +980,9 @@ MagickExport ImageType IdentifyImageGray(const Image *image,
   ImageType
     type = BilevelType;
 
+  MagickBooleanType
+    status = MagickTrue;
+
   ssize_t
     y;
 
@@ -994,7 +997,7 @@ MagickExport ImageType IdentifyImageGray(const Image *image,
     return(UndefinedType);
   image_view=AcquireVirtualCacheView(image,exception);
 #if defined(MAGICKCORE_OPENMP_SUPPORT)
-  #pragma omp parallel for schedule(static) shared(type) \
+  #pragma omp parallel for schedule(static) shared(status,type) \
     magick_number_threads(image,image,image->rows,2)
 #endif
   for (y=0; y < (ssize_t) image->rows; y++)
@@ -1005,19 +1008,19 @@ MagickExport ImageType IdentifyImageGray(const Image *image,
     ssize_t
       x;
 
-    if (type == UndefinedType)
+    if (status == MagickFalse)
       continue;
     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
     if (p == (const PixelPacket *) NULL)
       {
-        type=UndefinedType;
+        status=MagickFalse;
         continue;
       }
     for (x=0; x < (ssize_t) image->columns; x++)
     {
       if (IsPixelGray(p) == MagickFalse)
         {
-          type=UndefinedType;
+          status=MagickFalse;
           break;
         }
       if ((type == BilevelType) && (IsPixelMonochrome(p) == MagickFalse))
@@ -1028,6 +1031,8 @@ MagickExport ImageType IdentifyImageGray(const Image *image,
   image_view=DestroyCacheView(image_view);
   if ((type == GrayscaleType) && (image->matte != MagickFalse))
     type=GrayscaleMatteType;
+  if (status == MagickFalse)
+    return(UndefinedType);
   return(type);
 }