diff --git a/test/syscall_test/blocklists/epoll_test b/test/syscall_test/blocklists/epoll_test
index 658c924d8..0890177d6 100644
--- a/test/syscall_test/blocklists/epoll_test
+++ b/test/syscall_test/blocklists/epoll_test
@@ -6,4 +6,7 @@ EpollTest.EdgeTriggered_NoRandomSave
 EpollTest.OneshotAndEdgeTriggered
 EpollTest.CycleOfOneDisallowed
 EpollTest.CycleOfThreeDisallowed
-EpollTest.CloseFile
\ No newline at end of file
+EpollTest.CloseFile
+# `UnblockWithSignal` contains races. Better not to enable it.
+# See https://github.com/asterinas/asterinas/pull/1035 for details.
+EpollTest.UnblockWithSignal
diff --git a/test/syscall_test/run_syscall_test.sh b/test/syscall_test/run_syscall_test.sh
index 2a9f32dfc..7d711a64a 100755
--- a/test/syscall_test/run_syscall_test.sh
+++ b/test/syscall_test/run_syscall_test.sh
@@ -17,14 +17,14 @@ NC='\033[0m'
 
 get_blocklist_subtests(){
     if [ -f $BLOCKLIST_DIR/$1 ]; then
-        BLOCK=$(sed ':a;N;$!ba;s/\n/:/g' $BLOCKLIST_DIR/$1)
+        BLOCK=$(grep -v '^#' $BLOCKLIST_DIR/$1 | tr '\n' ':')
     else
         BLOCK=""
     fi
 
     for extra_dir in $EXTRA_BLOCKLISTS_DIRS ; do
         if [ -f $SCRIPT_DIR/$extra_dir/$1 ]; then
-            BLOCK="${BLOCK}:$(sed ':a;N;$!ba;s/\n/:/g' $SCRIPT_DIR/$extra_dir/$1)"
+            BLOCK="${BLOCK}:$(grep -v '^#' $SCRIPT_DIR/$extra_dir/$1 | tr '\n' ':')"
         fi
     done