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

[Tom Rini]

On Thu, Sep 29, 2022 at 12:02:43AM -0400, Sean Anderson wrote:
> On 9/28/22 22:36, Simon Glass wrote:
> > Hi Sean,
> > 
> > On Wed, 28 Sept 2022 at 15:50, Sean Anderson <seanga2 at gmail.com> wrote:
> > > 
> > > On 9/28/22 17:06, Simon Glass wrote:
> > > > Hi Sean,
> > > > 
> > > > On Wed, 28 Sept 2022 at 11:18, Sean Anderson <seanga2 at gmail.com> wrote:
> > > > > 
> > > > > 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 at 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 at gmail.com>
> > > > > 
> > > > > but do we need to instrument rEALLOc too?
> > > > 
> > > > We could, but I'd prefer to have a test which needs it first. Actually
> > > > realloc() calls malloc() in some cases, so we are already messing with
> > > > things here.
> > > 
> > > Maybe it would be better to do this at the "top-level" instead. E.g.
> > > redefine the malloc() et al macro. That way we remove any double-counting.
> > 
> > Yes, that makes sense. But again, I'd rather do this when we have a
> > use case for making realloc() fail.
> 
> Fine by me.
> 
> > BTW has dlmalloc been updated in recent years?
> 
> Apparently there's a 2.8.6, last updated in 2012 [1].

And I _think_ when I looked a year or two back there wasn't anything
standing out as an important to try and update change in there. But I
could be wrong and have missed something.

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 659 bytes
Desc: not available
URL: <https://lists.denx.de/pipermail/u-boot/attachments/20220929/cc7395c8/attachment.sig>