From: Catalin Marinas <catalin.marinas@arm.com>
To: Chen Jun <chenjun102@huawei.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, rui.xiang@huawei.com,
weiyongjun1@huawei.com
Subject: Re: [PATCH -next 2/5] mm/kmemleak: skip update_checksum for OBJECT_NO_SCAN objects
Date: Tue, 22 Sep 2020 10:03:48 +0100 [thread overview]
Message-ID: <20200922090346.GA15643@gaia> (raw)
In-Reply-To: <20200921020007.35803-3-chenjun102@huawei.com>
On Mon, Sep 21, 2020 at 02:00:04AM +0000, Chen Jun wrote:
> From: Wei Yongjun <weiyongjun1@huawei.com>
>
> Objects marked with OBJECT_NO_SCAN are never scanned.
> So there is no need to update checksum for them.
>
> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
> Signed-off-by: Chen Jun <chenjun102@huawei.com>
> ---
> mm/kmemleak.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/mm/kmemleak.c b/mm/kmemleak.c
> index b3f603fd9fc3..c09c6b59eda6 100644
> --- a/mm/kmemleak.c
> +++ b/mm/kmemleak.c
> @@ -1166,6 +1166,10 @@ static bool update_checksum(struct kmemleak_object *object)
> {
> u32 old_csum = object->checksum;
>
> + /* always return false for not scan object */
> + if (object->flags & OBJECT_NO_SCAN)
> + return false;
The reason for OBJECT_NO_SCAN is to avoid introducing more false
negatives. The point of the checksum is to reduce the false positives -
i.e. an object that is being modified between scans won't be considered
a (transient) leak even if kmemleak couldn't find a reference pointer to
it.
So please drop this patch.
--
Catalin
next prev parent reply other threads:[~2020-09-22 9:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 2:00 [PATCH -next 0/5] mm/kmemleak：support for percpu memory leak detect Chen Jun
2020-09-21 2:00 ` [PATCH -next 1/5] mm/kmemleak: make create_object return void Chen Jun
2020-09-22 9:57 ` Catalin Marinas
2020-09-21 2:00 ` [PATCH -next 2/5] mm/kmemleak: skip update_checksum for OBJECT_NO_SCAN objects Chen Jun
2020-09-22 9:03 ` Catalin Marinas [this message]
2020-09-21 2:00 ` [PATCH -next 3/5] mm/kmemleak: Add support for percpu memory leak detect Chen Jun
2020-09-22 9:57 ` Catalin Marinas
2020-09-28 14:08 ` chenjun (AM)
2020-09-28 14:16 ` Catalin Marinas
2020-09-21 2:00 ` [PATCH -next 4/5] mm/kmemleak-test: use %px instead of %p in print Chen Jun
2020-09-22 9:58 ` Catalin Marinas
2020-09-21 2:00 ` [PATCH -next 5/5] mm/kmemleak-test: Add a test case for alloc_percpu Chen Jun
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