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Date: Thu, 16 Mar 2017 14:57:35 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>, Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        syzkaller <syzkaller@googlegroups.com>
Subject: Re: perf: use-after-free in perf_release
Message-ID: <20170316135735.5psknfxe7e73gnag@hirez.programming.kicks-ass.net>
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On Wed, Mar 15, 2017 at 05:43:02PM +0100, Oleg Nesterov wrote:
> 	static inline int list_is_first(const struct list_head *list,
> 					const struct list_head *head)
> 	{
> 		return head->next == list;
> 	}
> 
> won't be symmetrical with list_is_last() we already have.

This is the one that makes sense to me though; that is, the current
list_is_last() doesn't make sense to me.

I would expect:

static inline int list_is_last(const struct list_head *list,
				const struct list_head *head)
{
	return head->prev == list
}

because @head is the list argument (yes, I know, horrible naming!).