[PATCH 5/5] test: self: add cleanup selftest

[Ahmad Fatoum]

The new __free() handlers have no user in the tree yet, so add a
selftest that exercises them: it checks that leaving the scope really
runs the cleanup, that NULL and error pointers are never passed to free(),
and that no_free_ptr() inhibits the cleanup.

Assisted-by: Claude:opus-5-1m
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 test/self/Kconfig   | 10 +++++
 test/self/Makefile  |  1 +
 test/self/cleanup.c | 89 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 100 insertions(+)
 create mode 100644 test/self/cleanup.c

diff --git a/test/self/Kconfig b/test/self/Kconfig
index 85a3ef790116..804fe6ac8d31 100644
--- a/test/self/Kconfig
+++ b/test/self/Kconfig
@@ -32,6 +32,7 @@ config SELFTEST_ENABLE_ALL
 	select SELFTEST_RANGE
 	select SELFTEST_PRINTF
 	select SELFTEST_MALLOC
+	select SELFTEST_CLEANUP
 	select SELFTEST_PROGRESS_NOTIFIER
 	select SELFTEST_OF_MANIPULATION
 	select SELFTEST_ENVIRONMENT_VARIABLES if ENVIRONMENT_VARIABLES
@@ -71,6 +72,15 @@ config SELFTEST_MALLOC
 	help
 	  Tests barebox memory allocator
 
+config SELFTEST_CLEANUP
+	bool "scope-based cleanup selftest"
+	help
+	  Tests the __free() cleanup handlers the barebox allocators define,
+	  i.e. that leaving a scope frees the buffer, that NULL and error
+	  pointers are never freed and that no_free_ptr() inhibits cleanup.
+
+	  If unsure, say n.
+
 config SELFTEST_TALLOC
 	bool "talloc() selftest"
 	help
diff --git a/test/self/Makefile b/test/self/Makefile
index 2bfdbb9949df..2fecab1f8ee3 100644
--- a/test/self/Makefile
+++ b/test/self/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_SELFTEST) += core.o
 obj-$(CONFIG_SELFTEST_BASE64) += base64.o
 obj-$(CONFIG_SELFTEST_RANGE) += range.o
 obj-$(CONFIG_SELFTEST_MALLOC) += malloc.o
+obj-$(CONFIG_SELFTEST_CLEANUP) += cleanup.o
 obj-$(CONFIG_SELFTEST_TALLOC) += talloc.o
 obj-$(CONFIG_SELFTEST_PRINTF) += printf.o
 CFLAGS_printf.o += -Wno-format-security -Wno-format
diff --git a/test/self/cleanup.c b/test/self/cleanup.c
new file mode 100644
index 000000000000..7a3b63cc897f
--- /dev/null
+++ b/test/self/cleanup.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <common.h>
+#include <bselftest.h>
+#include <malloc.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+BSELFTEST_GLOBALS();
+
+static void *freed[2];
+static int frees;
+static void count_free(void *mem)
+{
+	if (frees < ARRAY_SIZE(freed))
+		freed[frees] = mem;
+	frees++;
+	free(mem);
+}
+DEFINE_FREE(count_free, void *, if (!IS_ERR_OR_NULL(_T)) count_free(_T))
+
+static void test_cleanup(void)
+{
+	void *first, *second;
+
+	/* leaving the scope must free the buffer, and only then */
+	frees = 0;
+	{
+		void *p __free(count_free) = malloc(64);
+
+		assert_cond(p != NULL);
+		assert_cond(frees == 0);
+		first = p;
+	}
+	assert_cond(frees == 1);
+	assert_cond(freed[0] == first);
+	/* the variable defined last is freed first */
+	frees = 0;
+	{
+		void *p __free(count_free) = malloc(64);
+		void *q __free(count_free) = malloc(64);
+
+		first = p;
+		second = q;
+	}
+	assert_cond(frees == 2);
+	assert_cond(freed[0] == second);
+	assert_cond(freed[1] == first);
+
+	/* NULL must not reach the allocator */
+	{
+		void *p __free(free) = NULL;
+		void *q __free(free_sensitive) = NULL;
+		void *r __free(kfree) = NULL;
+		void *s __free(kfree_sensitive) = NULL;
+
+		assert_cond(p == NULL);
+		assert_cond(q == NULL);
+		assert_cond(r == NULL);
+		assert_cond(s == NULL);
+	}
+
+	/* and neither may error pointers */
+	{
+		void *p __free(free) = ERR_PTR(-EINVAL);
+		void *q __free(free_sensitive) = ERR_PTR(-EINVAL);
+		void *r __free(kfree) = ERR_PTR(-ENOMEM);
+		void *s __free(kfree_sensitive) = ERR_PTR(-ENOMEM);
+
+		assert_cond(IS_ERR(p));
+		assert_cond(IS_ERR(q));
+		assert_cond(IS_ERR(r));
+		assert_cond(IS_ERR(s));
+	}
+
+	/* no_free_ptr() inhibits the cleanup, so the buffer stays taken */
+	{
+		void *p __free(kfree) = kmalloc(64, GFP_KERNEL);
+		assert_cond(p != NULL);
+		first = no_free_ptr(p);
+	}
+	second = kmalloc(64, GFP_KERNEL);
+	assert_cond(second != first);
+	kfree(first);
+	kfree(second);
+}
+bselftest(core, test_cleanup);
-- 
2.47.3