Add a regression test

test/apps/mmap/mmap_beyond_the_file.c

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MPL-2.0
+
+#include <sys/mman.h>
+#include <sys/fcntl.h>
+#include <unistd.h>
+
+#include "../test.h"
+
+#define PAGE_SIZE 4096
+
+FN_TEST(mmap_beyond_the_file)
+{
+	const char *filename = "mmap_test_file";
+	int fd = TEST_SUCC(open(filename, O_CREAT | O_RDWR, 0600));
+	TEST_SUCC(ftruncate(fd, 2 * PAGE_SIZE));
+
+	char *addr = CHECK_WITH(mmap(NULL, 4 * PAGE_SIZE,
+				     PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0),
+				_ret != MAP_FAILED);
+	TEST_RES(addr[1 * PAGE_SIZE], _ret == 0);
+	// The following operation (if uncommented) would cause a segmentation fault.
+	// TEST_RES(addr[3 * PAGE_SIZE], _ret == 0);
+
+	TEST_SUCC(munmap(addr, 4 * PAGE_SIZE));
+
+	TEST_SUCC(close(fd));
+	TEST_SUCC(unlink(filename));
+}
+END_TEST()

test/apps/scripts/process.sh

@@ -29,6 +29,7 @@ itimer/setitimer
 itimer/timer_create
 mmap/mmap_and_fork
 mmap/mmap_and_mremap
+mmap/mmap_beyond_the_file
 mmap/mmap_shared_filebacked
 mmap/mmap_readahead
 mmap/mmap_vmrss