Re: [PATCH master 1/2] test: self: add basic testing for malloc()

[Sascha Hauer <sha@pengutronix.de>]

On Mon, May 23, 2022 at 08:27:55AM +0200, Ahmad Fatoum wrote:
> 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>
> ---
>  test/self/Kconfig  |  5 +++
>  test/self/Makefile |  1 +
>  test/self/malloc.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 97 insertions(+)
>  create mode 100644 test/self/malloc.c

Applied, thanks

Sascha

> 
> diff --git a/test/self/Kconfig b/test/self/Kconfig
> index 3340a9146ee2..cf11efe54486 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 05a2a6a236ec..65d01596b806 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 000000000000..c25b416b9751
> --- /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);
> -- 
> 2.30.2
> 
> 
> 

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