lib/test_meminit: add checks for the allocation functions

alloc_pages(), kmalloc() and vmalloc() are all memory allocation functions
which can return NULL when some internal memory failures happen.  So it is
better to check the return of them to catch the failure in time for better
test them.

Link: https://lkml.kernel.org/r/tencent_D44A49FFB420EDCCBFB9221C8D14DFE12908@qq.com
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/test_meminit.c

@@ -67,17 +67,24 @@ static int __init do_alloc_pages_order(int order, int *total_failures)
 	size_t size = PAGE_SIZE << order;
 
 	page = alloc_pages(GFP_KERNEL, order);
+	if (!page)
+		goto err;
 	buf = page_address(page);
 	fill_with_garbage(buf, size);
 	__free_pages(page, order);
 
 	page = alloc_pages(GFP_KERNEL, order);
+	if (!page)
+		goto err;
 	buf = page_address(page);
 	if (count_nonzero_bytes(buf, size))
 		(*total_failures)++;
 	fill_with_garbage(buf, size);
 	__free_pages(page, order);
 	return 1;
+err:
+	(*total_failures)++;
+	return 1;
 }
 
 /* Test the page allocator by calling alloc_pages with different orders. */
@@ -100,15 +107,22 @@ static int __init do_kmalloc_size(size_t size, int *total_failures)
 	void *buf;
 
 	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		goto err;
 	fill_with_garbage(buf, size);
 	kfree(buf);
 
 	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		goto err;
 	if (count_nonzero_bytes(buf, size))
 		(*total_failures)++;
 	fill_with_garbage(buf, size);
 	kfree(buf);
 	return 1;
+err:
+	(*total_failures)++;
+	return 1;
 }
 
 /* Test vmalloc() with given parameters. */
@@ -117,15 +131,22 @@ static int __init do_vmalloc_size(size_t size, int *total_failures)
 	void *buf;
 
 	buf = vmalloc(size);
+	if (!buf)
+		goto err;
 	fill_with_garbage(buf, size);
 	vfree(buf);
 
 	buf = vmalloc(size);
+	if (!buf)
+		goto err;
 	if (count_nonzero_bytes(buf, size))
 		(*total_failures)++;
 	fill_with_garbage(buf, size);
 	vfree(buf);
 	return 1;
+err:
+	(*total_failures)++;
+	return 1;
 }
 
 /* Test kmalloc()/vmalloc() by allocating objects of different sizes. */