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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 CBA8AC4332D for ; Wed, 23 Dec 2020 15:36:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BBCF2333E for ; Wed, 23 Dec 2020 15:36:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728412AbgLWPeI (ORCPT ); Wed, 23 Dec 2020 10:34:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:44872 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728349AbgLWPeE (ORCPT ); Wed, 23 Dec 2020 10:34:04 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 05ACB23371; Wed, 23 Dec 2020 15:33:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1608737584; bh=xU/1gEQBhMmzFwy+0MDHIawUXv4l2c99tIP6CZHlV/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ki3QfHMXs+8ea1QYFKFdF34JQ6if7hnJUSico0Jvbwx+gjfi6pgiwU128P0PXTyPc j65nQbD1yBUv7im4fq1NoFbLTo+RgPIgj4Z7lQQHlx9lx63s2UDJdni8J1Sf9R+jq7 F1pL36sBxmZ4ocK4neEVotMgBDphDcYRlcTUY74Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sai Prakash Ranjan , Mathieu Poirier Subject: [PATCH 5.10 18/40] coresight: etb10: Fix possible NULL ptr dereference in etb_enable_perf() Date: Wed, 23 Dec 2020 16:33:19 +0100 Message-Id: <20201223150516.429637132@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201223150515.553836647@linuxfoundation.org> References: <20201223150515.553836647@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sai Prakash Ranjan commit 22b2beaa7f166f550424cbb3b988aeaa7ef0425a upstream. 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, not ETR. 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 fix as ETF where we cache PID in alloc_buffer() callback which is called as the part of etm_setup_aux(). Fixes: 75d7dbd38824 ("coresight: etb10: Add support for CPU-wide trace scenarios") Cc: stable@vger.kernel.org Signed-off-by: Sai Prakash Ranjan Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20201127175256.1092685-11-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-etb10.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -176,6 +176,7 @@ static int etb_enable_perf(struct coresi 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 coresi } /* 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; @@ -383,6 +384,7 @@ static void *etb_alloc_buffer(struct cor if (!buf) return NULL; + buf->pid = task_pid_nr(event->owner); buf->snapshot = overwrite; buf->nr_pages = nr_pages; buf->data_pages = pages;