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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 8A0A2C388F9 for ; Thu, 22 Oct 2020 15:07:50 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E763F208B6 for ; Thu, 22 Oct 2020 15:07:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OvnLDfUq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E763F208B6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=bO6K6C4cmQviScz0Vk/EQVqxB5JKy6scQAy9Ep1Jpr0=; b=OvnLDfUq4mp+jQ4x9gwYS9oG7 JtDN0S2XaCb3bYF1qJrsUgLjDN67TUgDmILEnkQgg1oyIEzLUkFbhfwSWTBtrCyhdqfkTYtm4XQ73 rQimYga1Q4fYufnUp5UHs37ciH6Ls2QREyHTViaP5UqtpwkIh9Ktq2nxM5hP7YkWi/QNNGjF8rXrX ZHjnaX4yoKZhv5JFOjauaGURDcT2qY1P1PpVqIdJa1fQivlQPkQHmVwI5sxNi7JTndWyV7pIknDKL FBHcEWEXNofEuN0ZxCdgOB+3gPgZM5BYC6XVFuVrr5962OvblFinjAjJuvWZrO62JrfVQkRMxIUwE IqEztKk1w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kVcAR-0004L7-CX; Thu, 22 Oct 2020 15:06:15 +0000 Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kVcAP-0004Kr-Bo; Thu, 22 Oct 2020 15:06:13 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A4C0D3011C6; Thu, 22 Oct 2020 17:06:09 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 725A9203D0827; Thu, 22 Oct 2020 17:06:09 +0200 (CEST) Date: Thu, 22 Oct 2020 17:06:09 +0200 From: Peter Zijlstra To: Suzuki Poulose Subject: Re: [PATCHv2 2/4] coresight: tmc-etf: Fix NULL ptr dereference in tmc_enable_etf_sink_perf() Message-ID: <20201022150609.GI2611@hirez.programming.kicks-ass.net> References: <20201022113214.GD2611@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Sai Prakash Ranjan , Mathieu Poirier , Alexander Shishkin , linux-arm-msm@vger.kernel.org, coresight@lists.linaro.org, linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Stephen Boyd , Ingo Molnar , Namhyung Kim , Jiri Olsa , linux-arm-kernel@lists.infradead.org, Mike Leach Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Oct 22, 2020 at 02:30:21PM +0100, Suzuki Poulose wrote: > On 10/22/20 12:32 PM, Peter Zijlstra wrote: > > On Thu, Oct 22, 2020 at 04:27:52PM +0530, Sai Prakash Ranjan wrote: > > > > > Looking at the ETR and other places in the kernel, ETF and the > > > ETB are the only places trying to dereference the task(owner) > > > in tmc_enable_etf_sink_perf() which is also called from the > > > sched_in path as in the call trace. > > > > > @@ -391,6 +392,10 @@ static void *tmc_alloc_etf_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; > > > > > > This is *wrong*... why do you care about who owns the events? > > > > This is due to the special case of the CoreSight configuration, where > a "sink" (where the trace data is captured) is shared by multiple Trace > units. So, we could share the "sink" for multiple trace units if they > are tracing the events that belong to the same "perf" session. (The > userspace tool could decode the trace data based on the TraceID > in the trace packets). Is there a better way to do this ? I thought we added sink identification through perf_event_attr::config2 ? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel