From nobody Thu Oct 2 20:27:33 2025 Received: from mail-pg1-f174.google.com (mail-pg1-f174.google.com [209.85.215.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC88F2EC553 for ; Fri, 12 Sep 2025 10:13:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.174 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757671995; cv=none; b=gTth2c3p9tTYYeS8H9FJoCd+ZSzlZjQIVllbu1OGCxG4aNlpNYFEHoBYIjAW6QqzK3c8xrKUV7yeUVxHHEdC8WzleSrPc5NBtfLHZqb97nPmgiPjPVLu3+JoBGYArYRtX6FlnClmRT+gN5mwdpqL2quocoSa0dOfGls4xEGLBcU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757671995; c=relaxed/simple; bh=EgCZjLTIkqtRjqUx6K0w0F3NJZwiUfm4DLne+JUEvxw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UKBvpbYXS9XZWVY5AG9LuqFTq3q2K6T5Yxd9pyd0PuJYzPdH+WPtlC6vs/I174e4o7iLqF/PwsIPMeQTNJfw9nh7RpT36miW8sszp0FYjqJZG5AaslMcRplyPhMW8n/vSbxTsAqD0RJ8Xq4Uc77LXkhvvyNlbtlpqieRL0sid94= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=lnx3N7Q0; arc=none smtp.client-ip=209.85.215.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lnx3N7Q0" Received: by mail-pg1-f174.google.com with SMTP id 41be03b00d2f7-b49b56a3f27so1046232a12.1 for ; Fri, 12 Sep 2025 03:13:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1757671993; x=1758276793; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Hza3KqRNKGSLYWfBSKXFsxDeH0DXXBXA3429C+Yqz2A=; b=lnx3N7Q0UCWOROsQKLiSqOofasuN5O1eJ4c42khTCR4SEMDK2067Qp/33iXYQx6hI3 YPicD5Fl1RMw8sMdO+I5KMPG9sc70SRlTYhEGOtoYeE98QWBBgCAe9YqnhAH/krec7zT TOfBgS1VaAmH+Q6qSrXNhRxnx2ueTuLupH3V+jeJwr4KxVc2sEW0XQP6HUgIMk+48yON 3d+EYV6YFCxNn0liAtsoXz5Ukr9z9E+izbPH62lZn0vKsXk6FMU8iyeujm3mbygQdVfy GzI01wxXBiir9AuSZMeC7AvRtv+TKFMvvy6ChfuZNcseus/t1vmSTaasF7YcKfQZ4Iql rSeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757671993; x=1758276793; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Hza3KqRNKGSLYWfBSKXFsxDeH0DXXBXA3429C+Yqz2A=; b=f9uzypQ3Twmz9OjL+/AoQzYZ9y7Yqum6gA2tiwueb9IFOF5p0hwmSVMRDtZGXAJaQJ +EsGfZXm4kDU6jOm2U1XrMydKQ8vn8ogaZ7fVzn5DW/2987vA8T/z+1YThQ5AhSRwb/o al2vo03gnW0VtMbX1sj3mCTcYlgJ5GgzRnr1bOBirnyQBTCsFyAugrCHyHAsa6t3meK0 QuKyVSILaqHtQGSFmAMwc6xFUyZmNA3DOWVcZwXklwbUyZSB065WiPtEtG23dk0x2tUx meqtUl+PKhJr/gwKL+zBpCimdUJdmXmaXcs7aj/CmPDUSTPkYj3QEumGxa2nwX7w0q4A ecsQ== X-Forwarded-Encrypted: i=1; AJvYcCVMdIcgn3Yk61h0yP6ZJmVbmU/9TZmNGpA79w2hKaZO2aAs4Bi0taShvmJ2T+cq1hadq+LRLlyvLYmCRJ8=@vger.kernel.org X-Gm-Message-State: AOJu0YyKUtvTjJ4OVVBVJcLK1D9G7eoj6ah2CBg0iPgqTxOq4r4NpQ/H 42He0EMgOhpO935TmIBUd3R7HUqwyByW0zAhIH+eWbcqRI/zIDeUdin6 X-Gm-Gg: ASbGncsY+hTZqfkH1oi7qoP4/NXm8hW3hUE2OgeFnvuZOMVM/WgC0lIKQIzJN9J2fGd j2lkdbJD8eOwMS8j0kdaV+WyaRapPEGxehjInmV79GRycqb4Z5IXtjSZfXsymV715n4PqyWyzt6 Rx7IyApzihIwDyY0Ku2Wwq1xX4hSeJm7Q92K3eWiaQwdpNOpUKU6tPDCg4V6wdf7kNqpuyBcsdG ow6ViobtHu5zOuZPoWeiklsJ1wdwDEgyG8AsQhzgISXrDc+vdmvInav8wv/NXqNM0+SypTlROM5 VxS7+w3a/5xY27iJe9MmoDdrvBa6NlJ2SymMX/NjvlD2EeXdvTY2lgY2woFG/Dr+FIW17XoWXoN hjZToGp4VTt4IwLtUQwPDfz/bh1VbP2hp7AA= X-Google-Smtp-Source: AGHT+IG7f8OaGED6NtpM7NPcRiOM1jQkAe90+ggoUOI4OH0YlfR6qug9mcoSa6nxv/Hl/BMuWG/tLg== X-Received: by 2002:a17:902:c407:b0:24c:784c:4a90 with SMTP id d9443c01a7336-25d24cac4e3mr30450705ad.1.1757671992780; Fri, 12 Sep 2025 03:13:12 -0700 (PDT) Received: from localhost ([185.49.34.62]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-25c3ad33ed7sm45397685ad.102.2025.09.12.03.13.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Sep 2025 03:13:12 -0700 (PDT) From: Jinchao Wang To: Andrew Morton , Masami Hiramatsu , Peter Zijlstra , Mike Rapoport , Alexander Potapenko , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , 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 , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Kees Cook , Alice Ryhl , Sami Tolvanen , Miguel Ojeda , Masahiro Yamada , Rong Xu , Naveen N Rao , David Kaplan , Andrii Nakryiko , Jinjie Ruan , Nam Cao , workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-mm@kvack.org, llvm@lists.linux.dev, Andrey Ryabinin , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , kasan-dev@googlegroups.com, "David S. Miller" , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org Cc: Jinchao Wang Subject: [PATCH v4 15/21] mm/ksw: add test module Date: Fri, 12 Sep 2025 18:11:25 +0800 Message-ID: <20250912101145.465708-16-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250912101145.465708-1-wangjinchao600@gmail.com> References: <20250912101145.465708-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Introduce a separate test module to validate functionality in controlled scenarios, such as stack canary writes and simulated corruption. The module provides a proc interface (/proc/kstackwatch_test) that allows triggering specific test cases via simple commands: - test0: directly corrupt the canary to verify watch/fire behavior Test module is built with optimizations disabled to ensure predictable behavior. Signed-off-by: Jinchao Wang --- mm/Kconfig.debug | 10 ++++ mm/kstackwatch/Makefile | 6 +++ mm/kstackwatch/test.c | 115 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 131 insertions(+) create mode 100644 mm/kstackwatch/test.c diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index fdfc6e6d0dec..46c280280980 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -320,3 +320,13 @@ config KSTACK_WATCH the recursive depth of the monitored function. =20 If unsure, say N. + +config KSTACK_WATCH_TEST + tristate "KStackWatch Test Module" + depends on KSTACK_WATCH + help + This module provides controlled stack exhaustion and overflow scenarios + to verify the functionality of KStackWatch. It is particularly useful + for development and validation of the KStachWatch mechanism. + + If unsure, say N. diff --git a/mm/kstackwatch/Makefile b/mm/kstackwatch/Makefile index 84a46cb9a766..d007b8dcd1c6 100644 --- a/mm/kstackwatch/Makefile +++ b/mm/kstackwatch/Makefile @@ -1,2 +1,8 @@ obj-$(CONFIG_KSTACK_WATCH) +=3D kstackwatch.o kstackwatch-y :=3D kernel.o stack.o watch.o + +obj-$(CONFIG_KSTACK_WATCH_TEST) +=3D kstackwatch_test.o +kstackwatch_test-y :=3D test.o +CFLAGS_test.o :=3D -fno-inline \ + -fno-optimize-sibling-calls \ + -fno-pic -fno-pie -O0 -Og diff --git a/mm/kstackwatch/test.c b/mm/kstackwatch/test.c new file mode 100644 index 000000000000..76dbfb042067 --- /dev/null +++ b/mm/kstackwatch/test.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0 +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kstackwatch.h" + +MODULE_AUTHOR("Jinchao Wang"); +MODULE_DESCRIPTION("Simple KStackWatch Test Module"); +MODULE_LICENSE("GPL"); + +static struct proc_dir_entry *test_proc; +#define BUFFER_SIZE 4 +#define MAX_DEPTH 6 + +/* + * Test Case 0: Write to the canary position directly (Canary Test) + * use a u64 buffer array to ensure the canary will be placed + * corrupt the stack canary using the debug function + */ +static void canary_test_write(void) +{ + u64 buffer[BUFFER_SIZE]; + + pr_info("starting %s\n", __func__); + ksw_watch_show(); + ksw_watch_fire(); + + buffer[0] =3D 0; + + /* make sure the compiler do not drop assign action */ + barrier_data(buffer); + pr_info("canary write test completed\n"); +} + +static ssize_t test_proc_write(struct file *file, const char __user *buffe= r, + size_t count, loff_t *pos) +{ + char cmd[256]; + int test_num; + + if (count >=3D sizeof(cmd)) + return -EINVAL; + + if (copy_from_user(cmd, buffer, count)) + return -EFAULT; + + cmd[count] =3D '\0'; + strim(cmd); + + pr_info("received command: %s\n", cmd); + + if (sscanf(cmd, "test%d", &test_num) =3D=3D 1) { + switch (test_num) { + case 0: + pr_info("triggering canary write test\n"); + canary_test_write(); + break; + default: + pr_err("Unknown test number %d\n", test_num); + return -EINVAL; + } + } else { + pr_err("invalid command format. Use 'test1', 'test2', or 'test3'.\n"); + return -EINVAL; + } + + return count; +} + +static ssize_t test_proc_read(struct file *file, char __user *buffer, + size_t count, loff_t *pos) +{ + static const char usage[] =3D + "KStackWatch Simplified Test Module\n" + "=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n" + "Usage:\n" + " echo 'test0' > /proc/kstackwatch_test - Canary write test\n"; + + return simple_read_from_buffer(buffer, count, pos, usage, + strlen(usage)); +} + +static const struct proc_ops test_proc_ops =3D { + .proc_read =3D test_proc_read, + .proc_write =3D test_proc_write, +}; + +static int __init kstackwatch_test_init(void) +{ + test_proc =3D proc_create("kstackwatch_test", 0600, NULL, &test_proc_ops); + if (!test_proc) { + pr_err("Failed to create proc entry\n"); + return -ENOMEM; + } + pr_info("module loaded\n"); + return 0; +} + +static void __exit kstackwatch_test_exit(void) +{ + if (test_proc) + remove_proc_entry("kstackwatch_test", NULL); + pr_info("module unloaded\n"); +} + +module_init(kstackwatch_test_init); +module_exit(kstackwatch_test_exit); --=20 2.43.0