From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02E56C282CA for ; Tue, 12 Feb 2019 13:08:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C79D7217D9 for ; Tue, 12 Feb 2019 13:08:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="h4GOQt/J" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729321AbfBLNIT (ORCPT ); Tue, 12 Feb 2019 08:08:19 -0500 Received: from merlin.infradead.org ([205.233.59.134]:57148 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728874AbfBLNIR (ORCPT ); Tue, 12 Feb 2019 08:08:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=1KBTgh75R8ZmoVHa3UQsb+FSiCPuk264Z8EPNlrraw8=; b=h4GOQt/J2rbw7FwyXz9wEmEuf A1BrnDMlBZCLKQUXI5R9tM8uZBwGQyUy7Q4G2rxE/gY356iji3mroEttZcgyP2h82fgmqhRwY7aKp nhD16d5RfNSvDWVVF8qK/B0Xe5BUaSQxj/G3uqYgZGaAgpiH3N2ZmHmO44EmJVmdyRHfl5Y1K4paQ Y6mnQ0NbNJyh3KkQjrxZQHcUlj761cREREKsTyPoUkkmM6JACZMbKSI0GnANdb7pINEGt+bNnR+2x TY1SOrcj3ye/1P6qbG6+gnmpsYo8LuHNvhcmf62OOwUO0qxyRAlvltEkWOM6y/6NucUh14DRu67bh xWWt12r/A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gtXn4-0004YH-5Q; Tue, 12 Feb 2019 13:08:00 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5F54220D0C1D8; Tue, 12 Feb 2019 14:07:56 +0100 (CET) Date: Tue, 12 Feb 2019 14:07:56 +0100 From: Peter Zijlstra To: "Jin, Yao" Cc: Mark Rutland , linux-kernel@vger.kernel.org, julien.thierry@arm.com, Alexander Shishkin , Ingo Molnar , Jiri Olsa , Namhyung Kim , "Jin, Yao" , Arnaldo Carvalho de Melo Subject: Re: [PATCH] perf/core: don't WARN for impossible rb sizes Message-ID: <20190212130756.GH32494@hirez.programming.kicks-ass.net> References: <20190110142745.25495-1-mark.rutland@arm.com> <1f71da66-4783-0108-668c-cdffca499719@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1f71da66-4783-0108-668c-cdffca499719@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 12, 2019 at 10:42:38AM +0800, Jin, Yao wrote: > > diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c > > index 4a9937076331..309ef5a64af5 100644 > > --- a/kernel/events/ring_buffer.c > > +++ b/kernel/events/ring_buffer.c > > @@ -734,6 +734,9 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) > > size = sizeof(struct ring_buffer); > > size += nr_pages * sizeof(void *); > > + if (order_base_2(size) >= MAX_ORDER) > > + goto fail; > > + > > rb = kzalloc(size, GFP_KERNEL); Yes, Boris also send the entire morning bisecting this. The problem is that @size is in bytes and MAX_ORDER is in pages. That should be: if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)