diff --git a/raster/r.cost/flag.c b/raster/r.cost/flag.c
index b638ec9b68e..3cfed9ec2ff 100644
--- a/raster/r.cost/flag.c
+++ b/raster/r.cost/flag.c
@@ -20,7 +20,7 @@ FLAG *flag_create(int nrows, int ncols)
     if (!new_flag->array)
         G_fatal_error(_("Out of memory!"));
 
-    temp = (unsigned char *)G_malloc(nrows * new_flag->leng *
+    temp = (unsigned char *)G_malloc((size_t)nrows * new_flag->leng *
                                      sizeof(unsigned char));
 
     if (!temp)
diff --git a/raster/r.cost/main.c b/raster/r.cost/main.c
index 47ee40e2a9f..f2548b9d44f 100644
--- a/raster/r.cost/main.c
+++ b/raster/r.cost/main.c
@@ -513,7 +513,7 @@ int main(int argc, char *argv[])
         costs.cost_out = dnullval;
         costs.nearest = 0;
 
-        total_cells = nrows * ncols;
+        total_cells = (long)nrows * ncols;
 
         skip_nulls = Rast_is_d_null_value(&null_cost);
 
@@ -815,7 +815,7 @@ int main(int argc, char *argv[])
      */
 
     G_debug(1, "total cells: %ld", total_cells);
-    G_debug(1, "nrows x ncols: %d", nrows * ncols);
+    G_debug(1, "nrows x ncols: %ld", (long)nrows * ncols);
     G_message(_("Finding cost path..."));
     n_processed = 0;
     visited = flag_create(nrows, ncols);
diff --git a/raster/r.walk/flag.c b/raster/r.walk/flag.c
index b638ec9b68e..3cfed9ec2ff 100644
--- a/raster/r.walk/flag.c
+++ b/raster/r.walk/flag.c
@@ -20,7 +20,7 @@ FLAG *flag_create(int nrows, int ncols)
     if (!new_flag->array)
         G_fatal_error(_("Out of memory!"));
 
-    temp = (unsigned char *)G_malloc(nrows * new_flag->leng *
+    temp = (unsigned char *)G_malloc((size_t)nrows * new_flag->leng *
                                      sizeof(unsigned char));
 
     if (!temp)
diff --git a/raster/r.walk/main.c b/raster/r.walk/main.c
index a2e837deda1..ad1f9ee12ae 100644
--- a/raster/r.walk/main.c
+++ b/raster/r.walk/main.c
@@ -650,7 +650,7 @@ int main(int argc, char *argv[])
         costs.cost_out = dnullval;
         costs.nearest = 0;
 
-        total_cells = nrows * ncols;
+        total_cells = (long)nrows * ncols;
 
         skip_nulls = Rast_is_d_null_value(&null_cost);
 
@@ -976,7 +976,7 @@ int main(int argc, char *argv[])
      */
 
     G_debug(1, "total cells: %ld", total_cells);
-    G_debug(1, "nrows x ncols: %d", nrows * ncols);
+    G_debug(1, "nrows x ncols: %ld", (long)nrows * ncols);
     G_message(_("Finding cost path..."));
     n_processed = 0;
     visited = flag_create(nrows, ncols);