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Date: Mon, 27 Nov 2017 23:01:28 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Milind Chabbi <chabbi.milind@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>, Jiri Olsa <jolsa@kernel.org>,
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Subject: Re: [PATCH 4/6] hw_breakpoint: Factor out
 __modify_user_hw_breakpoint function
Message-ID: <20171127220128.kzgywcu5ucudaeyl@hirez.programming.kicks-ass.net>
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On Mon, Nov 27, 2017 at 01:50:30PM -0800, Milind Chabbi wrote:
> The possible checks is infinite

struct perf_event_attr is very much a finite data type.

Something as simple as:

	struct perf_event_attr tmp1 = new_attr, tmp2 = event->attr;

	tmp1.bp_type = tmp2.bp_type;
	tmp1.bp_addr = tmp2.bp_addr;
	tmp1.bp_len  = tmp2.bp_len;

	if (memcmp(&tmp1, &tmp2, sizeof(tmp1)))
		return -EINVAL;

would actually do the checks __modify_user_hw_breakpoint() needs to do.