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From: Marco Elver <elver@google.com>
To: Manjeet Pawar <manjeet.p@samsung.com>
Cc: glider@google.com, dvyukov@google.com, akpm@linux-foundation.org,
	kasan-dev@googlegroups.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, r.thapliyal@samsung.com,
	a.sahrawat@samsung.com, v.narang@samsung.com
Subject: Re: [PATCH] mm/kfence: Null check is added for return value of addr_to_metadata
Date: Fri, 24 Sep 2021 16:13:55 +0200	[thread overview]
Message-ID: <CANpmjNMcgUsdvXrvQHn+-y1w-z-6QAS+WJ27RB2DCnVxORRcuw@mail.gmail.com> (raw)
In-Reply-To: <1632485642-20625-1-git-send-email-manjeet.p@samsung.com>

On Fri, 24 Sept 2021 at 15:55, Manjeet Pawar <manjeet.p@samsung.com> wrote:
> This patch add null check for return value of addr_to_metadata().
> currently 'meta' is geting accessed without any NULL check but it is
> usually checked for this function.
>
> Signed-off-by: Manjeet Pawar <manjeet.p@samsung.com>

Your commit message does not make sense -- what bug did you encounter?

"usually checked for this function" is not a reason to add the check.
Adding a check like this could also hide genuine bugs, as meta should
never be NULL in __kfence_free(). If it is, we'd like to see a crash.

Did you read kfence_free() in include/linux/kfence.h? It already
prevents __kfence_free() being called with a non-KFENCE address.

Without a more thorough explanation, Nack.

Thanks,
-- Marco

      reply	other threads:[~2021-09-24 14:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20210924121457epcas5p39266266f9cef79177f2301a6a4f7d79a@epcas5p3.samsung.com>
2021-09-24 12:14 ` [PATCH] mm/kfence: Null check is added for return value of addr_to_metadata Manjeet Pawar
2021-09-24 14:13   ` Marco Elver [this message]

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