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 0053CC6FA8B for ; Wed, 21 Sep 2022 07:46:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230055AbiIUHqu (ORCPT ); Wed, 21 Sep 2022 03:46:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230368AbiIUHqr (ORCPT ); Wed, 21 Sep 2022 03:46:47 -0400 Received: from mail-ej1-x632.google.com (mail-ej1-x632.google.com [IPv6:2a00:1450:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D1AF75CE0; Wed, 21 Sep 2022 00:46:45 -0700 (PDT) Received: by mail-ej1-x632.google.com with SMTP id bj12so11587104ejb.13; Wed, 21 Sep 2022 00:46:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date; bh=Jvswl6qPZOcAXOYK+YaACZfbIZSk41zN4O+biBvkXG0=; b=YaRXBHJPol1fGJedZAViFdap5ub5A1LUkNMA7njQyXZrRZjoHQt2NhuGJNAwLA3/N6 eMX8JQjcigJ+P+X0ZNVkZv3IMd2OeoJzZv5kZ0TSe6A9IuEm5WSNwPTPVZCdHgnpu2BA ZEQLJsbH9GptoGHCKH65NQyaqavJHZKYNNnIdMDUsOhMDCaAl3hKybZlme+f61t55MWR MZl7AjazZAdbHkD0NimC/TxK+g2kW0WNEBpzDs3jXf4akHF048JoJlWm+DithTsi16XB IZs8I0wYBzRZTBKK3hERcY/SZ6ST9irLlcGGVSuy/4mYm07ryjg2PT3uXChek+QG4JBe vIkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date; bh=Jvswl6qPZOcAXOYK+YaACZfbIZSk41zN4O+biBvkXG0=; b=UrtsuI6kFHAUs0wQBVtJbrbR1gbDuGTCwwqLVeYcYxEZ/KAmxa5p3/PJWFLkWPI1IC nZIOw/mbw+P2q6lYnWCZCCMhCdJu/M6nLDJtS+7YXYT7hJ9Qf2aHLMQOZtOw1QcjuWpZ LBD1Z2jXnr9BmCcJb48+HzW8/utGsM7ofuUr0Hj5O1D+Fi1IG98PQ4dul0uIhJVSuPyQ 9Q2xWLWlD0jGf3Aa286EBjTmFqLUqtOv98fGNRM0wb/AUe898OBB94SEjd5SS9CuO1jN dSi19xb3zzR53YZdSo6A3tuYcOpnOx1Md4eh5Rb+EwVQvI4VaXpLz+vxOQF6pcqyl21G m6UQ== X-Gm-Message-State: ACrzQf3SLLkqMxpKFkw9GPbKvR6xxT7kp70x4VkVcGb88Y0O8BOZWkqa yKNhASeUGF7sYLtzSMwJwLW/RczptHs= X-Google-Smtp-Source: AMsMyM6i4J03MIvteEA1fiiRTP1mwoK51vO3ZiRjvim80xL0CQ2Wl+8A3wdnT2O/PqGP9v1ZjUZCrw== X-Received: by 2002:a17:906:9b92:b0:780:1f91:30fc with SMTP id dd18-20020a1709069b9200b007801f9130fcmr20501508ejc.142.1663746403733; Wed, 21 Sep 2022 00:46:43 -0700 (PDT) Received: from gmail.com (1F2EF035.nat.pool.telekom.hu. [31.46.240.53]) by smtp.gmail.com with ESMTPSA id r2-20020a170906a20200b0078020ae040csm869564ejy.219.2022.09.21.00.46.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Sep 2022 00:46:43 -0700 (PDT) Sender: Ingo Molnar Date: Wed, 21 Sep 2022 09:46:40 +0200 From: Ingo Molnar To: Li Zhong Cc: linux-perf-users@vger.kernel.org, bpf@vger.kernel.org, namhyung@kernel.org, jolsa@kernel.org, alexander.shishkin@linux.intel.com, mark.rutland@arm.com, acme@kernel.org, mingo@redhat.com, peterz@infradead.org Subject: Re: [PATCH v2] kernel/events/core: check return value of task_function_call() Message-ID: References: <20220919191611.1589661-1-floridsleeves@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220919191611.1589661-1-floridsleeves@gmail.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org * Li Zhong wrote: > From: lily > > Check the return value of task_function_call(), which could be error > code when the execution fails. We log this on info level. > > Signed-off-by: Li Zhong > --- > kernel/events/core.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 2621fd24ad26..3848631b009c 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -13520,7 +13520,10 @@ static void perf_cgroup_attach(struct cgroup_taskset *tset) > struct cgroup_subsys_state *css; > > cgroup_taskset_for_each(task, css, tset) > - task_function_call(task, __perf_cgroup_move, task); > + if (!task_function_call(task, __perf_cgroup_move, task)) { > + printk(KERN_INFO "perf: this process isn't running!\n"); > + continue; If this is a 'should never happen' condition, then this should really be WARN_ON_ONCE(). (If it can happen, then polluting the syslog is wrong.) Thanks, Ingo