[LibOS] Add testcase for reproducing checkpoint on mmap() issue

This test case will occasionally show the following error:

> while :; do gramine-direct fork_and_mmap; done
...
[P2:T3:fork_and_mmap] error: Sending IPC process-exit notification \
   failed: Connection reset by peer (ECONNRESET)

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

libos/test/regression/fork_and_mmap.c

@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/* Copyright (C) 2023 IBM Corporation
+ *                    Stefan Berger <stefanb@linux.ibm.com>
+ */
+
+#define _GNU_SOURCE
+#include <pthread.h>
+#include <err.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#define NUM_PAGES 1024
+
+int proceed = 0;
+
+static void* thread_func(void* arg) {
+    while (__atomic_load_n(&proceed, __ATOMIC_ACQUIRE) == 0)
+        usleep(1);
+    proceed = 0;
+
+    usleep(1);
+    pid_t pid = fork();
+    if (pid < 0) {
+        perror("fork failed\n");
+        exit(1);
+    }
+    if (pid > 0) {
+        while (__atomic_load_n(&proceed, __ATOMIC_ACQUIRE) == 0)
+            usleep(1);
+        printf("TEST OK\n");
+    } else {
+        printf("Child started\n");
+    }
+    exit(0);
+}
+
+int main(int argc, char** argv) {
+    long page_size = sysconf(_SC_PAGESIZE);
+    if (page_size == -1 && errno) {
+        err(1, "sysconf");
+    }
+
+
+    pthread_t forker;
+    if (pthread_create(&forker, NULL, thread_func, NULL) != 0) {
+        perror("pthread_create failed");
+        return 1;
+    }
+
+    proceed = 1;
+    while (__atomic_load_n(&proceed, __ATOMIC_ACQUIRE) == 1);
+
+    size_t i;
+    for (i = 0; i < NUM_PAGES; i++)
+        mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+
+    proceed = 1;
+    sleep(1);
+
+    return 0;
+}

libos/test/regression/meson.build

@@ -39,6 +39,7 @@ tests = {
     'fork_and_close': {},
     'fork_and_exec': {},
     'fork_and_mprotect': {},
+    'fork_and_mmap': {},
     'fork_and_munmap': {},
     'fork_and_pthread_create': {},
     'fork_and_sbrk': {},

libos/test/regression/test_libos.py

@@ -1023,6 +1023,13 @@ def test_164_fork_and_sbrk(self):
             stdout, _ = self.run_binary(['fork_and_sbrk'])
             self.assertIn("TEST OK", stdout)
 
+    def test_165_fork_and_mmap(self):
+        for _ in range(0, 10):
+            stdout, _ = self.run_binary(['fork_and_mmap'])
+            self.assertIn("TEST OK", stdout)
+            # error: Sending IPC process-exit notification failed: Connection reset by peer (ECONNRESET)
+            self.assertNotIn("ECONNRESET", stdout)
+
 class TC_31_Syscall(RegressionTestCase):
     def test_000_syscall_redirect(self):
         stdout, _ = self.run_binary(['syscall'])

libos/test/regression/tests.toml

@@ -42,6 +42,7 @@ manifests = [
   "fork_and_close",
   "fork_and_exec",
   "fork_and_mprotect",
+  "fork_and_mmap",
   "fork_and_munmap",
   "fork_and_pthread_create",
   "fork_and_sbrk",

libos/test/regression/tests_musl.toml

@@ -44,6 +44,7 @@ manifests = [
   "fork_and_close",
   "fork_and_exec",
   "fork_and_mprotect",
+  "fork_and_mmap",
   "fork_and_munmap",
   "fork_and_pthread_create",
   "fork_and_sbrk",