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 <[email protected]>
---
 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


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