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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 B9427C169C4 for ; Mon, 11 Feb 2019 16:10:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8EBE520700 for ; Mon, 11 Feb 2019 16:10:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729180AbfBKOYZ (ORCPT ); Mon, 11 Feb 2019 09:24:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:57540 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728097AbfBKOYU (ORCPT ); Mon, 11 Feb 2019 09:24:20 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4737120844; Mon, 11 Feb 2019 14:24:19 +0000 (UTC) Date: Mon, 11 Feb 2019 09:24:17 -0500 From: Steven Rostedt To: John Sperbeck Cc: wsa@the-dreams.de, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com Subject: Re: [PATCH v2] i2c: core-smbus: don't trace smbus_reply data on errors Message-ID: <20190211092417.7f211ee0@gandalf.local.home> In-Reply-To: <20190211034021.242932-1-jsperbeck@google.com> References: <20190205190849.GA2686@kunai> <20190211034021.242932-1-jsperbeck@google.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 10 Feb 2019 19:40:21 -0800 John Sperbeck wrote: > If an smbus transfer fails, there's no guarantee that the output > buffer was written. So, avoid trying to show the output buffer when > tracing after an error. This was 'mostly harmless', but would trip > up kasan checking if left-over cruft in byte 0 is a large length, > causing us to read from unwritten memory. This looks fine to me, but I'm not sure how the i2c maintainers feel, but I always require that a new patch version starts a new thread, and not be part of a older thread release (causes these patches to be hidden from those that read patches in threading mode). -- Steve > > Signed-off-by: John Sperbeck > --- > drivers/i2c/i2c-core-smbus.c | 2 +- > include/trace/events/smbus.h | 6 +++--- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c > index 9cd66cabb84f..132119112596 100644 > --- a/drivers/i2c/i2c-core-smbus.c > +++ b/drivers/i2c/i2c-core-smbus.c > @@ -585,7 +585,7 @@ s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, > trace: > /* If enabled, the reply tracepoint is conditional on read_write. */ > trace_smbus_reply(adapter, addr, flags, read_write, > - command, protocol, data); > + command, protocol, data, res); > trace_smbus_result(adapter, addr, flags, read_write, > command, protocol, res); > > diff --git a/include/trace/events/smbus.h b/include/trace/events/smbus.h > index d2fb6e1d3e10..a4892a187842 100644 > --- a/include/trace/events/smbus.h > +++ b/include/trace/events/smbus.h > @@ -138,9 +138,9 @@ TRACE_EVENT_CONDITION(smbus_reply, > TP_PROTO(const struct i2c_adapter *adap, > u16 addr, unsigned short flags, > char read_write, u8 command, int protocol, > - const union i2c_smbus_data *data), > - TP_ARGS(adap, addr, flags, read_write, command, protocol, data), > - TP_CONDITION(read_write == I2C_SMBUS_READ), > + const union i2c_smbus_data *data, int res), > + TP_ARGS(adap, addr, flags, read_write, command, protocol, data, res), > + TP_CONDITION(res >= 0 && read_write == I2C_SMBUS_READ), > TP_STRUCT__entry( > __field(int, adapter_nr ) > __field(__u16, addr )