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From: Andi Kleen <ak@linux.intel.com>
To: js1304@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
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        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Namhyung Kim <namhyung@kernel.org>,
        Wengang Wang <wen.gang.wang@oracle.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH 02/18] vchecker: introduce the valid access checker
References: <1511855333-3570-1-git-send-email-iamjoonsoo.kim@lge.com>
        <1511855333-3570-3-git-send-email-iamjoonsoo.kim@lge.com>
Date: Tue, 28 Nov 2017 11:41:08 -0800
In-Reply-To: <1511855333-3570-3-git-send-email-iamjoonsoo.kim@lge.com> (js's
        message of "Tue, 28 Nov 2017 16:48:37 +0900")
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js1304@gmail.com writes:

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Looks useful. Essentially unlimited hardware break points, combined
with slab.

Didn't do a full review, but noticed some things below.
> +
> +	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +
> +	if (copy_from_user(buf, ubuf, cnt)) {
> +		kfree(buf);
> +		return -EFAULT;
> +	}
> +
> +	if (isspace(buf[0]))
> +		remove = true;

and that may be uninitialized.

and the space changes the operation? That's a strange syntax.


> +	buf[cnt - 1] = '\0';

That's an underflow of one byte if cnt is 0.


-Andi