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=-14.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 C98A5C433E1 for ; Tue, 18 Aug 2020 21:19:45 +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 919152067C for ; Tue, 18 Aug 2020 21:19:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="w2ZScG3a" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 919152067C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Lj37VyyLXgwo4Ur5vZ58PIpnIj7rWxg6JfNJmmBi4/Y=; b=w2ZScG3aDd6DsyzSH/Hp72ltn U5p+F6VhXfiySFON36d2up3w3mJxrB2durqsJWiiLufE31f7//KoDoH73PtlXmM5uHrKLFhRXsGNo DSEIfjPpbgWEB4tbMkGgSh81yUeohTr6xxlBa3yiCeLA6plGl+AfQTDNtCkWK/N+fzdUknYO2EM6z zRBibP89gL/GNtCrwW0gcnVdmO+/yHCY4vTbiC0tVHiu2FpTR5J8DtFeJxk2dVnGSZ5cK9SOrGoO3 gdZmDmKzjnzLs9fN1khg9Or4eX3WOQOkIRUVjreCca9tZMKfaKYAdy+JdwcU0s7SbxwAxZjN44exp ep1bN2xmA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k88zY-0008Iu-Ab; Tue, 18 Aug 2020 21:18:00 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k88zV-0008I4-8s for linux-arm-kernel@lists.infradead.org; Tue, 18 Aug 2020 21:17:58 +0000 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 1446631B; Tue, 18 Aug 2020 14:17:53 -0700 (PDT) Received: from [192.168.122.166] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D07A33F71F; Tue, 18 Aug 2020 14:17:52 -0700 (PDT) Subject: Re: [PATCH] coresight: etm4x: Handle unreachable sink in perf mode To: Suzuki K Poulose , linux-arm-kernel@lists.infradead.org References: <20200818192931.168584-1-suzuki.poulose@arm.com> From: Jeremy Linton Message-ID: <14ff4a0b-8733-5ae4-d65a-b916e5c4a61c@arm.com> Date: Tue, 18 Aug 2020 16:17:41 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200818192931.168584-1-suzuki.poulose@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200818_171757_431807_41B9A0C0 X-CRM114-Status: GOOD ( 25.64 ) 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: coresight@lists.linaro.org, linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org, Mike Leach Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 8/18/20 2:29 PM, Suzuki K Poulose wrote: > If the specified/hinted sink is not reachable from a subset of the CPUs, > we could end up unable to trace the event on those CPUs. This > is the best effort we could do until we support 1:1 configurations. > Fail gracefully in such cases avoiding a WARN_ON, which can be easily > triggered by the user on certain platforms, like : I've tested it on 5.8 with "coresight: fix offset by one error in counting ports" on the N1SDP and i'm getting traces, and not seeing any further WARN's. Thanks for looking into this! Tested-by: Jeremy Linton > > [10919.513250] ------------[ cut here ]------------ > [10919.517861] WARNING: CPU: 2 PID: 24021 at > drivers/hwtracing/coresight/coresight-etm-perf.c:316 etm_event_start+0xf8/0x100 > ... > > [10919.564403] CPU: 2 PID: 24021 Comm: perf Not tainted 5.8.0+ #24 > [10919.570308] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--) > [10919.575865] pc : etm_event_start+0xf8/0x100 > [10919.580034] lr : etm_event_start+0x80/0x100 > [10919.584202] sp : fffffe001932f940 > [10919.587502] x29: fffffe001932f940 x28: fffffc834995f800 > [10919.592799] x27: 0000000000000000 x26: fffffe0011f3ced0 > [10919.598095] x25: fffffc837fce244c x24: fffffc837fce2448 > [10919.603391] x23: 0000000000000002 x22: fffffc8353529c00 > [10919.608688] x21: fffffc835bb31000 x20: 0000000000000000 > [10919.613984] x19: fffffc837fcdcc70 x18: 0000000000000000 > [10919.619281] x17: 0000000000000000 x16: 0000000000000000 > [10919.624577] x15: 0000000000000000 x14: 00000000000009f8 > [10919.629874] x13: 00000000000009f8 x12: 0000000000000018 > [10919.635170] x11: 0000000000000000 x10: 0000000000000000 > [10919.640467] x9 : fffffe00108cd168 x8 : 0000000000000000 > [10919.645763] x7 : 0000000000000020 x6 : 0000000000000001 > [10919.651059] x5 : 0000000000000002 x4 : 0000000000000001 > [10919.656356] x3 : 0000000000000000 x2 : 0000000000000000 > [10919.661652] x1 : fffffe836eb40000 x0 : 0000000000000000 > [10919.666949] Call trace: > [10919.669382] etm_event_start+0xf8/0x100 > [10919.673203] etm_event_add+0x40/0x60 > [10919.676765] event_sched_in.isra.134+0xcc/0x210 > [10919.681281] merge_sched_in+0xb0/0x2a8 > [10919.685017] visit_groups_merge.constprop.140+0x15c/0x4b8 > [10919.690400] ctx_sched_in+0x15c/0x170 > [10919.694048] perf_event_sched_in+0x6c/0xa0 > [10919.698130] ctx_resched+0x60/0xa0 > [10919.701517] perf_event_exec+0x288/0x2f0 > [10919.705425] begin_new_exec+0x4c8/0xf58 > [10919.709247] load_elf_binary+0x66c/0xf30 > [10919.713155] exec_binprm+0x15c/0x450 > [10919.716716] __do_execve_file+0x508/0x748 > [10919.720711] __arm64_sys_execve+0x40/0x50 > [10919.724707] do_el0_svc+0xf4/0x1b8 > [10919.728095] el0_sync_handler+0xf8/0x124 > [10919.732003] el0_sync+0x140/0x180 > > Fixes: f9d81a657bb8 ("coresight: perf: Allow tracing on hotplugged CPUs") > Reported-by: Jeremy Linton > Cc: Mathieu Poirier > Cc: Mike Leach > Signed-off-by: Suzuki K Poulose > --- > drivers/hwtracing/coresight/coresight-etm-perf.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c > index 1a3169e69bb1..9d61a71da96f 100644 > --- a/drivers/hwtracing/coresight/coresight-etm-perf.c > +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c > @@ -321,6 +321,16 @@ static void etm_event_start(struct perf_event *event, int flags) > if (!event_data) > goto fail; > > + /* > + * Check if this ETM is allowed to trace, as decided > + * at etm_setup_aux(). This could be due to an unreachable > + * sink from this ETM. We can't do much in this case if > + * the sink was specified or hinted to the driver. For > + * now, simply don't record anything on this ETM. > + */ > + if (!cpumask_test_cpu(cpu, &event_data->mask)) > + goto fail_end_stop; > + > path = etm_event_cpu_path(event_data, cpu); > /* We need a sink, no need to continue without one */ > sink = coresight_get_sink(path); > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel