Re: [PATCH v2 12/45] test: Support testing malloc() failures

[Sean Anderson <seanga2@gmail.com>]

On 9/6/22 22:27, Simon Glass wrote:
> It is helpful to test that out-of-memory checks work correctly in code
> that calls malloc().
> 
> Add a simple way to force failure after a given number of malloc() calls.
> 
> Fix a header guard to avoid a build error on sandbox_vpl.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
> 
> (no changes since v1)
> 
>   arch/sandbox/include/asm/malloc.h |  1 +
>   common/dlmalloc.c                 | 19 +++++++++++++++++++
>   include/malloc.h                  | 12 ++++++++++++
>   test/test-main.c                  |  1 +
>   4 files changed, 33 insertions(+)
> 
> diff --git a/arch/sandbox/include/asm/malloc.h b/arch/sandbox/include/asm/malloc.h
> index a1467b5eadd..8aaaa9cb87b 100644
> --- a/arch/sandbox/include/asm/malloc.h
> +++ b/arch/sandbox/include/asm/malloc.h
> @@ -6,6 +6,7 @@
>    */
>   
>   #ifndef __ASM_MALLOC_H
> +#define __ASM_MALLOC_H
>   
>   void *malloc(size_t size);
>   void free(void *ptr);
> diff --git a/common/dlmalloc.c b/common/dlmalloc.c
> index f48cd2a333d..41c7230424c 100644
> --- a/common/dlmalloc.c
> +++ b/common/dlmalloc.c
> @@ -596,6 +596,9 @@ ulong mem_malloc_start = 0;
>   ulong mem_malloc_end = 0;
>   ulong mem_malloc_brk = 0;
>   
> +static bool malloc_testing;	/* enable test mode */
> +static int malloc_max_allocs;	/* return NULL after this many calls to malloc() */
> +
>   void *sbrk(ptrdiff_t increment)
>   {
>   	ulong old = mem_malloc_brk;
> @@ -1307,6 +1310,11 @@ Void_t* mALLOc(bytes) size_t bytes;
>   		return malloc_simple(bytes);
>   #endif
>   
> +  if (CONFIG_IS_ENABLED(UNIT_TEST) && malloc_testing) {
> +    if (--malloc_max_allocs < 0)
> +      return NULL;
> +  }
> +
>     /* check if mem_malloc_init() was run */
>     if ((mem_malloc_start == 0) && (mem_malloc_end == 0)) {
>       /* not initialized yet */
> @@ -2470,6 +2478,17 @@ int initf_malloc(void)
>   	return 0;
>   }
>   
> +void malloc_enable_testing(int max_allocs)
> +{
> +	malloc_testing = true;
> +	malloc_max_allocs = max_allocs;
> +}
> +
> +void malloc_disable_testing(void)
> +{
> +	malloc_testing = false;
> +}
> +
>   /*
>   
>   History:
> diff --git a/include/malloc.h b/include/malloc.h
> index e8c8b254c0d..161ccbd1298 100644
> --- a/include/malloc.h
> +++ b/include/malloc.h
> @@ -883,6 +883,18 @@ extern Void_t*     sbrk();
>   
>   void malloc_simple_info(void);
>   
> +/**
> + * malloc_enable_testing() - Put malloc() into test mode
> + *
> + * This only works if UNIT_TESTING is enabled
> + *
> + * @max_allocs: return -ENOMEM after max_allocs calls to malloc()
> + */
> +void malloc_enable_testing(int max_allocs);
> +
> +/** malloc_disable_testing() - Put malloc() into normal mode */
> +void malloc_disable_testing(void);
> +
>   #if CONFIG_IS_ENABLED(SYS_MALLOC_SIMPLE)
>   #define malloc malloc_simple
>   #define realloc realloc_simple
> diff --git a/test/test-main.c b/test/test-main.c
> index c65cbd7c351..5b6b5ba5bbe 100644
> --- a/test/test-main.c
> +++ b/test/test-main.c
> @@ -46,6 +46,7 @@ static int dm_test_pre_run(struct unit_test_state *uts)
>   	uts->force_fail_alloc = false;
>   	uts->skip_post_probe = false;
>   	gd->dm_root = NULL;
> +	malloc_disable_testing();
>   	if (CONFIG_IS_ENABLED(UT_DM) && !CONFIG_IS_ENABLED(OF_PLATDATA))
>   		memset(dm_testdrv_op_count, '\0', sizeof(dm_testdrv_op_count));
>   	arch_reset_for_test();

Reviewed-by: Sean Anderson <seanga2@gmail.com>

but do we need to instrument rEALLOc too?