diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index ea2ea947b50..e0e9a00a02e 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -569,6 +569,10 @@ patchPhase() {
 
     for i in $patches; do
         header "applying patch $i" 3
+        if [ ! -r $i ]; then
+            echo "file $i does not exist or not readable"
+            exit 1
+        fi
         local uncompress=cat
         case $i in
             *.gz)