Re: [PATCH v2 1/2] mm, kasan: don't call kasan_krealloc() from ksize().

[Alexander Potapenko]

On Fri, Apr 22, 2016 at 11:32 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 13 Apr 2016 13:20:09 +0200 Alexander Potapenko <glider@xxxxxxxxxx> wrote:
>
>> Instead of calling kasan_krealloc(), which replaces the memory allocation
>> stack ID (if stack depot is used), just unpoison the whole memory chunk.
>
> I don't understand why these two patches exist.  Bugfix?  Cleanup?
> Optimization?
It's incorrect to call kasan_krealloc() from ksize(), because the
former may touch the allocation metadata (it does so for the SLAB
allocator).
Yes, this is a bugfix.
>
> I had to change kmalloc_tests_init() a bit due to
> mm-kasan-initial-memory-quarantine-implementation.patch:
>
>         kasan_stack_oob();
>         kasan_global_oob();
>  #ifdef CONFIG_SLAB
>         kasan_quarantine_cache();
>  #endif
> +       ksize_unpoisons_memory();
>         return -EAGAIN;
>  }
>
> Please check.
Ack.



-- 
Alexander Potapenko
Software Engineer

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