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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52BCEC433F5 for ; Tue, 17 May 2022 11:42:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D701C6B0073; Tue, 17 May 2022 07:42:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D203A6B0074; Tue, 17 May 2022 07:42:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BE6F66B0075; Tue, 17 May 2022 07:42:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id AF3286B0073 for ; Tue, 17 May 2022 07:42:11 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 8CD8120AB1 for ; Tue, 17 May 2022 11:42:11 +0000 (UTC) X-FDA: 79475046462.23.5B123CF Received: from mail-wr1-f42.google.com (mail-wr1-f42.google.com [209.85.221.42]) by imf08.hostedemail.com (Postfix) with ESMTP id F02891600B6 for ; Tue, 17 May 2022 11:41:53 +0000 (UTC) Received: by mail-wr1-f42.google.com with SMTP id r23so8352328wrr.2 for ; Tue, 17 May 2022 04:42:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=cHqZzZFU2KlkZ0e38q0rPqPRXApRGQ0ABOWC87CWLJw=; b=IYeMCvycGgP5xP2mtMf4VadsRe/pBe1PJYBeIc5RgEqwRO9GF9HmZgnnF7ILbMRaqY 5lTymMJHrfPUZUUJlKwTC6oOJ4piiSdK5QEHcEnhdjYhbXRVMtaIPYiXH5MC+r3PBWSI IHpF8yBU2oqBiCMsPzknAqEiZIbi6Q8wxHsqpcOlz6u7RjCgkiT0TMMZnnxm9fJWYCBj uO0VtaZgGfJKSETsCnrbaLOXaBOC6HxkydIUaBQQVJbUNXRQpPOrTW7r6VJ4C92NZQRy nThrIJWJBYnPgevp1R06hOtJ2HW3kawsxzkIVo4Qd6G6Qn2/9E5giFUg7U8kDd5kbmlY m6ZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=cHqZzZFU2KlkZ0e38q0rPqPRXApRGQ0ABOWC87CWLJw=; b=Hj0ixMIWePLbGX4lGZjpXq0eoEKKl2wVKzf3BNy9hMWADZhObsjTD4lvo6UDiVStWm QSv5hUidD/j5s8eTdFkWQcAbEPZaVudlGmgfeOY2QAdO2ugNd6Unkdn2fJXhpnyGZSw0 a+KOrVCLulOmogJWz5urhdulxzcem8up9lguMvYdwQpbRGLpKCtgMR1Oi050vGtbeGpz UqIflGn8hyF2AzJE7D1J/T1EK84EDk2XntzntU+orwVIpeeBO1ycUS7Xum1Hhr0SXfpT lg4Hlm0YyNFlnG+jghrDLSwbJg5OcS5iL87dMQb0M0lFbBr4QUWLdsC0ds6RfboA2wxH A6iQ== X-Gm-Message-State: AOAM530bp+DAFDqleOh31f9DwJC7shG/t5r9Qd+gxJexsE5Fi+ju6kLh a8NMI0Lan0zg4j6gFdjo15hzRA== X-Google-Smtp-Source: ABdhPJy6NuhjosgqGpgVS7j8cAupMepDQ2wOa/t7uAyk0w/niLm9K8+1FOJazNlVIK7TgzTsD/OTAQ== X-Received: by 2002:a5d:5541:0:b0:20d:a89:ae21 with SMTP id g1-20020a5d5541000000b0020d0a89ae21mr7386448wrw.176.1652787729545; Tue, 17 May 2022 04:42:09 -0700 (PDT) Received: from elver.google.com ([2a00:79e0:15:13:c38a:158c:29c:8a84]) by smtp.gmail.com with ESMTPSA id 22-20020a05600c021600b003942a244ed1sm1633888wmi.22.2022.05.17.04.42.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 May 2022 04:42:08 -0700 (PDT) Date: Tue, 17 May 2022 13:42:03 +0200 From: Marco Elver To: Jackie Liu Cc: glider@google.com, dvyukov@google.com, kasan-dev@googlegroups.com, linux-mm@kvack.org Subject: Re: [PATCH] mm/kfence: print disabling or re-enabling message Message-ID: References: <20220517111551.4077061-1-liu.yun@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220517111551.4077061-1-liu.yun@linux.dev> User-Agent: Mutt/2.1.4 (2021-12-11) X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: F02891600B6 Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=IYeMCvyc; spf=pass (imf08.hostedemail.com: domain of elver@google.com designates 209.85.221.42 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspam-User: X-Stat-Signature: f98bzxk38kdg8idcaax6nrbjurje1xxj X-HE-Tag: 1652787713-714680 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, May 17, 2022 at 07:15PM +0800, Jackie Liu wrote: > From: Jackie Liu > > By printing information, we can friendly prompt the status change > information of kfence by dmesg. > > Signed-off-by: Jackie Liu Personally, I've never found this useful. If I want to get the current accurate state of KFENCE enablement, I just look at /sys/kernel/debug/kfence/stats. Nevertheless, some comments below. > --- > mm/kfence/core.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index 11a954763be9..beb552089b67 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -67,8 +67,11 @@ static int param_set_sample_interval(const char *val, const struct kernel_param > if (ret < 0) > return ret; > > - if (!num) /* Using 0 to indicate KFENCE is disabled. */ > + if (!num) { > + /* Using 0 to indicate KFENCE is disabled. */ > WRITE_ONCE(kfence_enabled, false); > + pr_info("KFENCE is disabled.\n"); This will also print on boot if kfence.sample_interval=0 is passed. This is ugly. We also have a pr_fmt, and writing "KFENCE" again is ugly, too. And adding '.' at the end of these short log lines is not something done much in the kernel, and also ugly. So what you want is this fixup: diff --git a/mm/kfence/core.c b/mm/kfence/core.c index beb552089b67..de5bcf2609fe 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -67,10 +67,11 @@ static int param_set_sample_interval(const char *val, const struct kernel_param if (ret < 0) return ret; + /* Using 0 to indicate KFENCE is disabled. */ if (!num) { - /* Using 0 to indicate KFENCE is disabled. */ + if (READ_ONCE(kfence_enabled)) + pr_info("disabled\n"); WRITE_ONCE(kfence_enabled, false); - pr_info("KFENCE is disabled.\n"); } *((unsigned long *)kp->arg) = num; @@ -877,7 +878,7 @@ static int kfence_enable_late(void) WRITE_ONCE(kfence_enabled, true); queue_delayed_work(system_unbound_wq, &kfence_timer, 0); - pr_info("KFENCE is re-enabled.\n"); + pr_info("re-enabled\n"); return 0; }