Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751878Ab0ARN4P (ORCPT ); Mon, 18 Jan 2010 08:56:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751395Ab0ARN4O (ORCPT ); Mon, 18 Jan 2010 08:56:14 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:53055 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751336Ab0ARN4N (ORCPT ); Mon, 18 Jan 2010 08:56:13 -0500 Subject: Re: [PATCH 1/3] perf_event: fix race in perf_swevent_get_recursion_context() From: Peter Zijlstra To: Xiao Guangrong Cc: Ingo Molnar , Frederic Weisbecker , Paul Mackerras , LKML In-Reply-To: <4B54654A.4090601@cn.fujitsu.com> References: <4B54654A.4090601@cn.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 18 Jan 2010 14:55:58 +0100 Message-ID: <1263822958.4283.560.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 606 Lines: 17 On Mon, 2010-01-18 at 21:42 +0800, Xiao Guangrong wrote: > It only disable preemption in perf_swevent_get_recursion_context() > it can't avoid race of hard-irq and NMI > > In this patch, we use atomic operation to avoid it and reduce > cpu_ctx->recursion size, it also make this patch no need diable > preemption Uhm why? This patch looks terminally broken -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/