Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754948Ab3CSNCg (ORCPT ); Tue, 19 Mar 2013 09:02:36 -0400 Received: from mail-qe0-f50.google.com ([209.85.128.50]:55676 "EHLO mail-qe0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753526Ab3CSNCe (ORCPT ); Tue, 19 Mar 2013 09:02:34 -0400 MIME-Version: 1.0 In-Reply-To: <1363697902.22553.43.camel@laptop> References: <20130318134645.GA3278@quad> <1363696984.22553.41.camel@laptop> <1363697902.22553.43.camel@laptop> Date: Tue, 19 Mar 2013 14:02:34 +0100 Message-ID: Subject: Re: [PATCH] perf,x86: fix uninitialized pt_regs in intel_pmu_drain_bts_buffer() From: Stephane Eranian To: Peter Zijlstra Cc: LKML , "mingo@elte.hu" , Jiri Olsa , Salman Qazi , "ak@linux.intel.com" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1027 Lines: 28 On Tue, Mar 19, 2013 at 1:58 PM, Peter Zijlstra wrote: > On Tue, 2013-03-19 at 13:50 +0100, Stephane Eranian wrote: >> > Should we not replace: >> > >> > regs.ip = 0; >> > >> > with that memset? It avoids the memset work in a few cases and >> removes >> > the then superfluous clearing of the IP field. >> > >> We could drop it because it's covered by the memset(). > > Yeah, but also place the memset a little lower than you did, avoids the > stack writes when not needed. > Ok, I get it now. Yes, we can move it after the test and drop reg.val = 0. >> The issue here was that you eventually end up in code_segment_base() >> which >> looks at other uninitialized fields in pt_regs and may cause breakage. > > Right, your changelog said so ;-) > -- 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/