From patchwork Thu Oct 22 10:57:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sai Prakash Ranjan X-Patchwork-Id: 11850825 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9CB0D14B7 for ; Thu, 22 Oct 2020 10:58:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F9E6223FB for ; Thu, 22 Oct 2020 10:58:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="budEWbUv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2896847AbgJVK6g (ORCPT ); Thu, 22 Oct 2020 06:58:36 -0400 Received: from z5.mailgun.us ([104.130.96.5]:41941 "EHLO z5.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2896826AbgJVK6d (ORCPT ); Thu, 22 Oct 2020 06:58:33 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1603364312; h=Content-Transfer-Encoding: MIME-Version: References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=PokbucJp42uifsTw4R9V/FJUxMajlU8DaNmXfSbY0sk=; b=budEWbUvObnpuJSbMlWXj4UmIEL6HNZIexXoheRaR6rkNYwpmbbsMwU+ijftVx3zljghODO1 UvDYNBBZepjYAmWBMSWiamxf84aX2agJ6B+i4m0P0xmSiuJuEa6geOV74S0vfpp3ZeyK6URI apFSNa417uLJorZvuKY2s7Bdke0= X-Mailgun-Sending-Ip: 104.130.96.5 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-west-2.postgun.com with SMTP id 5f9165d883370fa1c1007f30 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 22 Oct 2020 10:58:32 GMT Sender: saiprakash.ranjan=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 56E86C43391; Thu, 22 Oct 2020 10:58:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=ALL_TRUSTED,BAYES_00,SPF_FAIL, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from blr-ubuntu-253.qualcomm.com (blr-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.18.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan) by smtp.codeaurora.org (Postfix) with ESMTPSA id 9EC6FC43387; Thu, 22 Oct 2020 10:58:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 9EC6FC43387 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=saiprakash.ranjan@codeaurora.org From: Sai Prakash Ranjan To: Mathieu Poirier , Suzuki K Poulose , Mike Leach , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim Cc: coresight@lists.linaro.org, Stephen Boyd , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sai Prakash Ranjan Subject: [PATCHv2 3/4] coresight: etb10: Fix possible NULL ptr dereference in etb_enable_perf() Date: Thu, 22 Oct 2020 16:27:53 +0530 Message-Id: <8c649ac9c3119edb1fff218c972909a48cdda122.1603363729.git.saiprakash.ranjan@codeaurora.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org There was a report of NULL pointer dereference in ETF enable path for perf CS mode with PID monitoring. It is almost 100% reproducible when the process to monitor is something very active such as chrome and with ETF as the sink. But code path shows that ETB has a similar path as ETF, so there could be possible NULL pointer dereference crash in ETB as well. Currently in a bid to find the pid, the owner is dereferenced via task_pid_nr() call in etb_enable_perf() and with owner being NULL, we can get a NULL pointer dereference, so have a similar change as ETF where we cache PID in alloc_buffer() callback which is called as the part of etm_setup_aux(). This will reduce the task_pid_nr() function call overheads as well. In addition to this, add a check to validate event->owner before dereferencing it to fix any possible NULL pointer dereference crashes and check for kernel events. Fixes: 75d7dbd38824 ("coresight: etb10: Add support for CPU-wide trace scenarios") Suggested-by: Suzuki K Poulose Signed-off-by: Sai Prakash Ranjan --- drivers/hwtracing/coresight/coresight-etb10.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index 248cc82c838e..9d2f1ab0e29e 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -176,6 +176,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data) unsigned long flags; struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); struct perf_output_handle *handle = data; + struct cs_buffers *buf = etm_perf_sink_config(handle); spin_lock_irqsave(&drvdata->spinlock, flags); @@ -186,7 +187,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data) } /* Get a handle on the pid of the process to monitor */ - pid = task_pid_nr(handle->event->owner); + pid = buf->pid; if (drvdata->pid != -1 && drvdata->pid != pid) { ret = -EBUSY; @@ -376,6 +377,10 @@ static void *etb_alloc_buffer(struct coresight_device *csdev, { int node; struct cs_buffers *buf; + struct task_struct *task = READ_ONCE(event->owner); + + if (!task || is_kernel_event(event)) + return NULL; node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); @@ -383,6 +388,7 @@ static void *etb_alloc_buffer(struct coresight_device *csdev, if (!buf) return NULL; + buf->pid = task_pid_nr(task); buf->snapshot = overwrite; buf->nr_pages = nr_pages; buf->data_pages = pages;