test: self: add basic testing for malloc()

Surprisingly, the TLSF allocator is prone to overflow. Add some tests
that trigger this behavior. These tests run to success with dlmalloc,
but some of them fail under tlsf when compiled for 32-bit:

  test_malloc:40: unexpectedly succeeded to malloc(SIZE_MAX)
  test_malloc:61: unexpectedly succeeded to (tmp = realloc(p, 0xf0000000))
  test_malloc:63: unexpectedly succeeded to tmp = realloc(p, SIZE_MAX)
  ERROR: malloc: failed 3 out of 12 tests

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20220523062756.774153-1-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 97 insertions, 0 deletions

diff --git a/test/self/Kconfig b/test/self/Kconfig
index 3340a9146e..cf11efe544 100644
--- a/test/self/Kconfig
+++ b/test/self/Kconfig
@@ -32,6 +32,11 @@ config SELFTEST_ENABLE_ALL
 	help
 	  Selects all self-tests compatible with current configuration
 
+config SELFTEST_MALLOC
+	bool "malloc() selftest"
+	help
+	  Tests barebox memory allocator
+
 config SELFTEST_PRINTF
 	bool "printf selftest"
 	help
diff --git a/test/self/Makefile b/test/self/Makefile
index 05a2a6a236..65d01596b8 100644
--- a/test/self/Makefile
+++ b/test/self/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_SELFTEST) += core.o
+obj-$(CONFIG_SELFTEST_MALLOC) += malloc.o
 obj-$(CONFIG_SELFTEST_PRINTF) += printf.o
 obj-$(CONFIG_SELFTEST_PROGRESS_NOTIFIER) += progress-notifier.o
 obj-$(CONFIG_SELFTEST_OF_MANIPULATION) += of_manipulation.o of_manipulation.dtb.o
diff --git a/test/self/malloc.c b/test/self/malloc.c
new file mode 100644
index 0000000000..c25b416b97
--- /dev/null
+++ b/test/self/malloc.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <common.h>
+#include <bselftest.h>
+#include <malloc.h>
+#include <memory.h>
+#include <linux/sizes.h>
+
+BSELFTEST_GLOBALS();
+
+static void __expect(bool cond, bool expect,
+		     const char *condstr, const char *func, int line)
+{
+	total_tests++;
+	if (cond != expect) {
+		failed_tests++;
+		printf("%s:%d: %s to %s\n", func, line,
+		       expect ? "failed" : "unexpectedly succeeded",
+		       condstr);
+	}
+}
+
+#define expect_alloc_ok(cond) \
+	__expect((cond), true, #cond, __func__, __LINE__)
+
+#define expect_alloc_fail(cond) \
+	__expect((cond), false, #cond, __func__, __LINE__)
+
+static void test_malloc(void)
+{
+	size_t mem_malloc_size = mem_malloc_end() - mem_malloc_start();
+	u8 *p, *tmp;
+
+	pr_debug("mem_malloc_size = %zu\n", mem_malloc_size);
+
+	/* System libc when built for sandbox may have overcommit, so
+	 * doing very big allocations without actual use may succeed
+	 * unlike in-barebox allocators, so skip these tests in that
+	 * case
+	 */
+	if (IS_ENABLED(CONFIG_MALLOC_LIBC)) {
+		pr_info("built with host libc allocator: Skipping tests that may trigger overcommit\n");
+		mem_malloc_size = 0;
+	}
+
+	expect_alloc_ok(p = malloc(1));
+	free(p);
+
+	if (mem_malloc_size) {
+		expect_alloc_fail(malloc(SIZE_MAX));
+
+		if (0xf0000000 > mem_malloc_size) {
+			expect_alloc_fail((tmp = malloc(0xf0000000)));
+			free(tmp);
+		}
+	} else {
+		skipped_tests += 2;
+	}
+
+	p = realloc(NULL, 1);
+	expect_alloc_ok(p = realloc(NULL, 1));
+
+	*p = 0x42;
+
+	expect_alloc_ok(tmp = realloc(p, 2));
+
+	p = tmp;
+	__expect(*p == 0x42, true, "reread after realloc", __func__, __LINE__);
+
+	if (mem_malloc_size) {
+		expect_alloc_fail(tmp = realloc(p, mem_malloc_size));
+
+		if (0xf0000000 > mem_malloc_size)
+			expect_alloc_fail((tmp = realloc(p, 0xf0000000)));
+
+		expect_alloc_fail(tmp = realloc(p, SIZE_MAX));
+
+	} else {
+		skipped_tests += 3;
+	}
+
+	free(p);
+
+	expect_alloc_ok(p = malloc(0));
+	expect_alloc_ok(tmp = malloc(0));
+
+	__expect(p != tmp, true, "allocate distinct 0-size buffers", __func__, __LINE__);
+}
+bselftest(core, test_malloc);