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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A4A7C0015E for ; Mon, 24 Jul 2023 15:38:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229905AbjGXPiQ (ORCPT ); Mon, 24 Jul 2023 11:38:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230026AbjGXPiO (ORCPT ); Mon, 24 Jul 2023 11:38:14 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 8CABB121 for ; Mon, 24 Jul 2023 08:38:13 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 71E0B11FB; Mon, 24 Jul 2023 08:38:56 -0700 (PDT) Received: from [10.57.1.47] (unknown [10.57.1.47]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4CC6F3F67D; Mon, 24 Jul 2023 08:38:12 -0700 (PDT) Message-ID: <61f11ffe-473c-a36e-c51d-9e526a6fd375@arm.com> Date: Mon, 24 Jul 2023 16:38:10 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [RESEND PATCH] coresight: tmc: Explicit type conversions to prevent integer overflow Content-Language: en-US To: Ruidong Tian , coresight@lists.linaro.org Cc: mike.leach@linaro.org, alexander.shishkin@linux.intel.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20230714084349.31567-1-tianruidong@linux.alibaba.com> From: James Clark In-Reply-To: <20230714084349.31567-1-tianruidong@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/07/2023 09:43, Ruidong Tian wrote: > Perf cs_etm session will failed when AUX buffer > 1G. > > perf record -C 0 -m ,2G -e cs_etm// -- taskset -c 0 ls > failed to mmap with 12 (Cannot allocate memory) > > In coresight tmc driver, "nr_pages << PAGE_SHIFT" will overflow when > nr_pages >= 0x80000(correspond to 1G AUX buffer). Explicit convert nr_pages > to 64 bit to avoid overflow. > Hi Ruidong, I couldn't reproduce this exact issue with the error message in the commit message. Is it not another manifestation related to this change [1]? I don't actually get any error message, but I was able to get a warning in dmesg even with [1] applied. Does the overflow not result in a successful session but with the wrong buffer size? I think the change makes sense, but maybe we also need a check for MAX_ORDER because I can trigger the same WARN_ON from [1]. Or maybe I'm a bit confused because of the other change and not being able to reproduce this exactly coming at the same time. [1]: https://lore.kernel.org/bpf/20230711014120.53461-1-xueshuai@linux.alibaba.com/ Thanks James > Signed-off-by: Ruidong Tian > --- > drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +- > drivers/hwtracing/coresight/coresight-tmc.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c > index 766325de0e29..1425ecd1cf78 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c > +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c > @@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event, > * than the size requested via sysfs. > */ > if ((nr_pages << PAGE_SHIFT) > drvdata->size) { > - etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT), > + etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT), > 0, node, NULL); > if (!IS_ERR(etr_buf)) > goto done; > diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h > index b97da39652d2..0ee48c5ba764 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc.h > +++ b/drivers/hwtracing/coresight/coresight-tmc.h > @@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table, > static inline unsigned long > tmc_sg_table_buf_size(struct tmc_sg_table *sg_table) > { > - return sg_table->data_pages.nr_pages << PAGE_SHIFT; > + return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT; > } > > struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);