On Mon, May 2, 2016 at 7:36 AM, <chengang@xxxxxxxxxxxxxxxx> wrote:
> From: Chen Gang <chengang@xxxxxxxxxxxxxxxx>
>
> According to kasan_[dis|en]able_current() comments and the kasan_depth'
> s initialization, if kasan_depth is zero, it means disable.
The comments for those functions are really poor, but there's nothing
there that says kasan_depth==0 disables KASAN.
Actually, kasan_report_enabled() is currently the only place that
denotes the semantics of kasan_depth, so it couldn't be wrong.
init_task.kasan_depth is 1 during bootstrap and is then set to zero by
kasan_init()
For every other thread, current->kasan_depth is zero-initialized.
> So need use "!!kasan_depth" instead of "!kasan_depth" for checking
> enable.
>
> Signed-off-by: Chen Gang <gang.chen.5i5j@xxxxxxxxx>
> ---
> mm/kasan/kasan.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 7da78a6..6464b8f 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -102,7 +102,7 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
>
> static inline bool kasan_report_enabled(void)
> {
> - return !current->kasan_depth;
> + return !!current->kasan_depth;
> }
>
> void kasan_report(unsigned long addr, size_t size,
> --
> 1.9.3
>
--
Alexander Potapenko
Software Engineer
Google Germany GmbH
Erika-Mann-Straße, 33
80636 München
Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg
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