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Date:   Tue, 3 Jul 2018 15:41:39 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     Mathieu Poirier <mathieu.poirier@linaro.org>
Cc:     peterz@infradead.org, acme@kernel.org, mingo@redhat.com,
        tglx@linutronix.de, alexander.shishkin@linux.intel.com,
        schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
        will.deacon@arm.com, mark.rutland@arm.com, namhyung@kernel.org,
        adrian.hunter@intel.com, ast@kernel.org,
        gregkh@linuxfoundation.org, hpa@zytor.com,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 5/6] perf/core: Use ioctl to communicate driver
 configuration to kernel
Message-ID: <20180703134139.GB3728@krava>
References: <1530570810-28929-1-git-send-email-mathieu.poirier@linaro.org>
 <1530570810-28929-6-git-send-email-mathieu.poirier@linaro.org>
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On Mon, Jul 02, 2018 at 04:33:29PM -0600, Mathieu Poirier wrote:

SNIP

> +	ret = 0;
> +out:
> +	return ret;
> +}
> +
> +static int perf_event_set_drv_config(struct perf_event *event, void __user *arg)
> +{
> +	int ret = -EINVAL;
> +	char *config_str;
> +
> +	config_str = strndup_user(arg, PAGE_SIZE);
> +	if (IS_ERR(config_str))
> +		return PTR_ERR(config_str);
> +
> +	if (has_drv_config(event))

would it be better to make this check before
the alloc/copy data from user takes place?

jirka