From: Alexander Potapenko <glider@google.com>
To: Chen Gang <chengang@emindsoft.com.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Dmitriy Vyukov <dvyukov@google.com>,
kasan-dev <kasan-dev@googlegroups.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Chen Gang <gang.chen.5i5j@gmail.com>
Subject: Re: [PATCH] mm/kasan/kasan.h: Fix boolean checking issue for kasan_report_enabled()
Date: Mon, 2 May 2016 13:34:52 +0200 [thread overview]
Message-ID: <CAG_fn=UdYpYQCyQ0JGD6VxNvNmZBChX-cTdaR5xm1S6BgP-Gnw@mail.gmail.com> (raw)
In-Reply-To: <1462167374-6321-1-git-send-email-chengang@emindsoft.com.cn>
On Mon, May 2, 2016 at 7:36 AM, <chengang@emindsoft.com.cn> wrote:
> From: Chen Gang <chengang@emindsoft.com.cn>
>
> 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@gmail.com>
> ---
> 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
next prev parent reply other threads:[~2016-05-02 11:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-02 5:36 [PATCH] mm/kasan/kasan.h: Fix boolean checking issue for kasan_report_enabled() chengang
2016-05-02 8:26 ` Dmitry Vyukov
2016-05-02 11:11 ` Chen Gang
2016-05-02 11:21 ` Dmitry Vyukov
2016-05-02 12:27 ` Chen Gang
2016-05-02 12:42 ` Alexander Potapenko
2016-05-02 13:51 ` Chen Gang
2016-05-02 14:23 ` Alexander Potapenko
2016-05-02 15:13 ` Chen Gang
2016-05-02 15:35 ` Alexander Potapenko
2016-05-02 16:23 ` Chen Gang
2016-05-02 16:38 ` Chen Gang
2016-05-14 3:30 ` Chen Gang
2016-05-02 11:34 ` Alexander Potapenko [this message]
2016-05-02 12:09 ` Chen Gang
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