[LibOS] Add testcase for reproducing checkpoint on sbrk issue

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

libos/test/regression/fork_and_sbrk.c

@@ -0,0 +1,57 @@
+/* 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>
+
+int proceed = 0;
+
+static void* thread_func(void* arg) {
+    while (__atomic_load_n(&proceed, __ATOMIC_ACQUIRE) == 0)
+        usleep(1);
+    proceed = 0;
+
+    usleep(10);
+    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) {
+    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 < 1024; i++) {
+        sbrk(0x10000);
+        sbrk(-0x10000);
+    }
+
+    proceed = 1;
+    sleep(1);
+
+    return 0;
+}

libos/test/regression/meson.build

@@ -41,6 +41,7 @@ tests = {
     'fork_and_mprotect': {},
     'fork_and_munmap': {},
     'fork_and_pthread_create': {},
+    'fork_and_sbrk': {},
     'fp_multithread': {
         'c_args': '-fno-builtin',  # see comment in the test's source
         'link_args': '-lm',

libos/test/regression/test_libos.py

@@ -1018,6 +1018,11 @@ def test_163_fork_and_pthread_create(self):
             stdout, _ = self.run_binary(['fork_and_pthread_create'])
             self.assertIn("TEST OK", stdout)
 
+    def test_164_fork_and_sbrk(self):
+        for _ in range(0, 10):
+            stdout, _ = self.run_binary(['fork_and_sbrk'])
+            self.assertIn("TEST OK", stdout)
+
 class TC_31_Syscall(RegressionTestCase):
     def test_000_syscall_redirect(self):
         stdout, _ = self.run_binary(['syscall'])

libos/test/regression/tests.toml

@@ -44,6 +44,7 @@ manifests = [
   "fork_and_mprotect",
   "fork_and_munmap",
   "fork_and_pthread_create",
+  "fork_and_sbrk",
   "fork_disallowed",
   "fp_multithread",
   "fstat_cwd",

libos/test/regression/tests_musl.toml

@@ -46,6 +46,7 @@ manifests = [
   "fork_and_mprotect",
   "fork_and_munmap",
   "fork_and_pthread_create",
+  "fork_and_sbrk",
   "fork_disallowed",
   "fp_multithread",
   "fstat_cwd",