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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D82D6CA1015 for ; Thu, 4 Sep 2025 07:51:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2A7C48E0007; Thu, 4 Sep 2025 03:51:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 27FD38E0002; Thu, 4 Sep 2025 03:51:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1BC298E0007; Thu, 4 Sep 2025 03:51:58 -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 0BAA98E0002 for ; Thu, 4 Sep 2025 03:51:58 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id A57175C2D9 for ; Thu, 4 Sep 2025 07:51:57 +0000 (UTC) X-FDA: 83850799074.12.D4F4E7B Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf26.hostedemail.com (Postfix) with ESMTP id D6EAF140003 for ; Thu, 4 Sep 2025 07:51:55 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=dCfOKTW5; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf26.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1756972316; a=rsa-sha256; cv=none; b=as7nYulUH//aKgqUhUP25zJSi5UH9io7PaYUUskEQrytrML5wrZgvNG/G3KMzYu0H/vl+O Kq6eWKUP2cMi6wYEOd21DlVfpdwWTWcT0rIszlg9qt/yXan4z4oDAymERn0w2xA4bilrnp 10rx5JFdKqWhxiTEIs6EO/RxQx8gZZ0= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=dCfOKTW5; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf26.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756972316; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=LeIvzZVxBDGvPFwISXv5rpIJ8ywPIJ1UY9bkrlehq0k=; b=DG5ZY1WYI6wv2JINeRwaSN5ZYgTNwLst2gNcT9El8r5V9AKr7mgy8Di3j9EmoecnMGf6fw 4mmvtx42tAG9087COEbvolM75sUsn418BG0KPa7cVZN1XUPL8JZz02L2Ev20GSvUrjskji JOAmP24iZyxm+l4iMD8L4svgr1vaMso= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 6B02E43AA2; Thu, 4 Sep 2025 07:51:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3835BC4CEF0; Thu, 4 Sep 2025 07:51:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756972314; bh=rE0KWJrKeJt22T4AYZywb92G0O/oP+xSleFmSknemCA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dCfOKTW5QmsGiI7lfLidL4A7U/TqtlUK8B/Z+xXpeK+xOv/o1wrjKImlBIm7qoqyp vWrVbcvDgLaQtrmSWW9QnceFY+vaWOifv+eJybBINP9rST+hO74eb4Hh1G6Wt2hT2x oYH7Xt4OZmWo0rLzgu7qils5+FxRsbp4e+uUQ+8jKyYxWZeWCUnNCkDNyYWUdjqt7g bJ8p8EcEjqpIpV+HifHSHDE67CtJhrDcNFsZZRE5m7jVHfjhWAlsDpevdqJdKUJbMq 3I219i+m22wZU7OsFAA2EZ6VaPOVZSpZ+B3A1yVRyCh2uk7Et7rKEY6W+5qJAvvCe4 y76jW/0hht3XQ== Date: Thu, 4 Sep 2025 10:51:41 +0300 From: Mike Rapoport To: Jinchao Wang Cc: Andrew Morton , Masami Hiramatsu , "Naveen N . Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , linux-perf-users@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 03/18] mm/ksw: add /proc/kstackwatch interface Message-ID: References: <20250904002126.1514566-1-wangjinchao600@gmail.com> <20250904002126.1514566-4-wangjinchao600@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250904002126.1514566-4-wangjinchao600@gmail.com> X-Rspamd-Queue-Id: D6EAF140003 X-Stat-Signature: oqcf3g9c85d4msfrbccrdu64r1q84tnu X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1756972315-451177 X-HE-Meta: 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 hTBiNAbQ Er4HzlyqSXVYTLdldH+Bik3OevQBNZ2phk3DIJwwGKa9VgtBlWUyLYK2KELdtebBD+tSMBjW6ast/MPgtEJc+cIiuESLAs/EA8qWBwoPAvXopTNIfCJlpArteKPUYOzJR3EObp2125XC1WWoFM5U58QkdDxFy/qo75V6F5s3NlWwL54+Wmdgz0cY3dp5ATvMWq9Hsq9Ev96QOV9fc/8LobPqAQ6Dm3Qq/Zvmswl9zEFlua12N6wO3SdTZzodtntsUruJmZQ8fjoYiX/RJ9HRp9/j7E61dYRgxzkBFiyFZGGGyp4fYkM8o5N4bBguF50G1r9/+Rn1h3yGCAQiHhaUCRgv+TOZkcjHbDPt7 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: List-Subscribe: List-Unsubscribe: On Thu, Sep 04, 2025 at 08:21:00AM +0800, Jinchao Wang wrote: > Provide the /proc/kstackwatch file to read or update the KSW configuration. > Writing a valid config string starts watching; empty input stops watching. > Invalid input stops watching and reports an error. > > Allocate a ksw_config struct on module init and free it on exit. > Manage watching state with ksw_start_watching() and ksw_stop_watching(). > > Signed-off-by: Jinchao Wang > --- > mm/kstackwatch/kernel.c | 140 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 140 insertions(+) > > diff --git a/mm/kstackwatch/kernel.c b/mm/kstackwatch/kernel.c > index 4a6dc49449fe..95ade95abde1 100644 > --- a/mm/kstackwatch/kernel.c > +++ b/mm/kstackwatch/kernel.c > @@ -1,7 +1,10 @@ > // SPDX-License-Identifier: GPL-2.0 > #include > #include > +#include > +#include > #include > +#include > > #include "kstackwatch.h" > > @@ -9,6 +12,29 @@ MODULE_AUTHOR("Jinchao Wang"); > MODULE_DESCRIPTION("Kernel Stack Watch"); > MODULE_LICENSE("GPL"); > > +struct ksw_config *ksw_config; Does a global ksw_config imply that this is a singleton? What happens when there are several "echo .. > /proc/kstackwatch"? And even more interesting what happens if they are parallel? > +bool watching_active; > + > +bool panic_on_catch; > +module_param(panic_on_catch, bool, 0644); > +MODULE_PARM_DESC(panic_on_catch, > + "Trigger a kernel panic immediately on corruption catch"); > + > +static int ksw_start_watching(void) > +{ > + watching_active = true; > + > + pr_info("KSW: start watching %s\n", ksw_config->config_str); > + return 0; > +} > + > +static void ksw_stop_watching(void) > +{ > + watching_active = false; > + > + pr_info("KSW: stop watching %s\n", ksw_config->config_str); This module is overly verbose. Do you really need all the printks? > +} ... > static int __init kstackwatch_init(void) > { > + ksw_config = kmalloc(sizeof(*ksw_config), GFP_KERNEL); > + if (!ksw_config) > + return -ENOMEM; > + > + /* Create proc interface */ > + if (!proc_create("kstackwatch", 0644, NULL, &kstackwatch_proc_ops)) { ksw_config must be freed here > + pr_err("KSW: create proc kstackwatch fail"); > + return -ENOMEM; > + } > + > pr_info("KSW: module loaded\n"); > pr_info("KSW: usage:\n"); > pr_info("KSW: echo 'function+ip_offset[+depth] [local_var_offset:local_var_len]' > /proc/kstackwatch\n"); > @@ -85,6 +217,14 @@ static int __init kstackwatch_init(void) > > static void __exit kstackwatch_exit(void) > { > + /* Cleanup active watching */ > + if (watching_active) > + ksw_stop_watching(); > + > + /* Remove proc interface */ > + remove_proc_entry("kstackwatch", NULL); > + kfree(ksw_config); > + > pr_info("KSW: Module unloaded\n"); > } > > -- > 2.43.0 > -- Sincerely yours, Mike.