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 629ECCAC5B9 for ; Tue, 30 Sep 2025 02:45:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C172C8E0030; Mon, 29 Sep 2025 22:45:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BEDBB8E0002; Mon, 29 Sep 2025 22:45:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ADC5C8E0030; Mon, 29 Sep 2025 22:45:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 9CED28E0002 for ; Mon, 29 Sep 2025 22:45:36 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 5FE7659917 for ; Tue, 30 Sep 2025 02:45:36 +0000 (UTC) X-FDA: 83944375872.02.6A4550C Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) by imf23.hostedemail.com (Postfix) with ESMTP id 829A9140002 for ; Tue, 30 Sep 2025 02:45:34 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=lGoMIUdn; spf=pass (imf23.hostedemail.com: domain of wangjinchao600@gmail.com designates 209.85.210.180 as permitted sender) smtp.mailfrom=wangjinchao600@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1759200334; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=1RtyZdLa/V9peD4vyIt7vF3g+yVd+tHG9wNYuCcZNH8=; b=HgSQOmBfPNvaTf3mZ9ejhM0lRmNL7oIuC+eo2nAXFtnNSuaDpl7BqHNKjR+hCRsAqezBom A/G0Vfvm+cHPxdBmknjcI7Pk6+226Tu7Neg97wev1vMXOhFWETOI1bs+FlmgmwNQLPWAyw HE/ZwMXjCxU97ZMyj1MO/U72iXh/+jI= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759200334; a=rsa-sha256; cv=none; b=W7ug/mplHHpjiy+ZOOeveUi7ofJPtgM54GMFUfkCd5OPN+L7tCDxgaWqwmqiBc+BEGvqz3 I0jhGBJDhfJoNCmBWyBnVvaw825SRV7cU7ADilAqeJmiSW8xKd0M0N3TdweYfRajG0YAeJ D+dUHKoMs1haQGpzF9Rbys8/pFIdEwM= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=lGoMIUdn; spf=pass (imf23.hostedemail.com: domain of wangjinchao600@gmail.com designates 209.85.210.180 as permitted sender) smtp.mailfrom=wangjinchao600@gmail.com; dmarc=pass (policy=none) header.from=gmail.com Received: by mail-pf1-f180.google.com with SMTP id d2e1a72fcca58-781206cce18so3597495b3a.0 for ; Mon, 29 Sep 2025 19:45:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1759200333; x=1759805133; darn=kvack.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=1RtyZdLa/V9peD4vyIt7vF3g+yVd+tHG9wNYuCcZNH8=; b=lGoMIUdnhEAQiihIIMoSoLq8XFqQY8mki3H8nhsbmOWgHX7/id/6+3MGshnp6go0mu xOf7HxMY2LUgrQbudYQp1DEb4KK09VVNW+4ibp1BwZsbdnOEW0ERlxHab9t2pFVLU13n O3d+DtGWqFsCePiyJ12NWz5/2nXpDMIZE+ApF3q3kMImeGil8MwJEuGq1cCmMiLtCevy k/KGQi93cdZ4c2N7WKZ5lc13FCbFvZAIyLD8f0huzp3U/CPk4D9I4Ie6X7HhYJA3KtqC YUn/VkfTnaWjPuy5wVtTTD7HgZdGlVd2v1+6FGPrBHww8GNhwR9DJhrKjqPxYT8YtwyM /nIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759200333; x=1759805133; 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=1RtyZdLa/V9peD4vyIt7vF3g+yVd+tHG9wNYuCcZNH8=; b=g5U0uOdWw3S943dI00mGPc+tlKShOYR+nF4MGubj0I8mebBykqv4AiNoerVOSbYEq1 zCJ+n9no4rxz0RfaD5gug2FposXchoPJqNChCni/KwYUfS4p2/ariNAYDbljj2Lqz+Mx E2XUo67ci/48/sI/t3Hc8sy4kCNqCKrVAbefCcqPcBgCfxLN3+0FkXewH7Z3CrHOSKNT 5cIF0Wz1LfbfEz/LjF3EQwCP4LZ57QY6IHPpcGuTqTinvZQYT1bm/rQdqETnyTO2pcSu RjpNJ1Jn6Nk2RImi1bid3dTQiLX54xofIQu5kb+xUzfW2aHI+5DktN28NeexT1t4EeDq yleA== X-Forwarded-Encrypted: i=1; AJvYcCWToa+rTjOUHNK45s3NxtWqhZqcyezQ+JcRocvNqD1t8cURATRtgsUA9KlLF8oujhU1iFAJsBTAXA==@kvack.org X-Gm-Message-State: AOJu0YyL0cdPPygZClquZ6+itpeOrfBlhtNaX8PAL9UO7bO3p8AEYqPa 9B4zbW2gabH+h7sdU2Es1L1WV2GBvGnIYB35cEwvzDfpRRF3nX0fYeEu X-Gm-Gg: ASbGnctukx+XOUtN/EsjYZJTeBhEp3lfvrMxc2oE2tplN0HKjprVOf4NTopDF6GNjcO 7HPYUDme+PaRI69Hpnt683cbYarDA/xeQsQcyFVZlf7C67KbU8eX7f7pLrxLwTgHx2XH9HTgHcV tvn6KaovWoicwBDhPwNRistlwdDDVcm+LRMLdptk0dXA1bnGrUaPl+k0aAEsfoB/Oyk9i0NK17G WZe1r1BayEGrZTjfq3KmcSVpmjFjOa7xrXuq8nZigh+KWxRy2N6Fwkj/AqKJfJlFmB0MG6xc+09 uF4t6RL/YneXrquJgxIv0HnoSD4/nm509TOcyNho4QY07fe9Gpli7z4x+Cc1UxoAPCXA5do8uoB zYwTuqvrtBGWu2R9MkE9OBXQsPDggPM3dvHnGgPmXHJIe1zppw8vQRuqrnUquKTjR1t+YAruTh7 6U X-Google-Smtp-Source: AGHT+IEsif2bxHXvYWWChBgM/szcD1tJlw9HGin9oZWPM2Y8lHrYniUGiEidosj0MGkcbXMNhwhy+Q== X-Received: by 2002:a05:6a20:9c8c:b0:248:ef8:66df with SMTP id adf61e73a8af0-317732b6b3cmr3072325637.30.1759200333340; Mon, 29 Sep 2025 19:45:33 -0700 (PDT) Received: from localhost ([45.142.167.196]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-b57c53bb255sm12683002a12.5.2025.09.29.19.45.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Sep 2025 19:45:32 -0700 (PDT) From: Jinchao Wang To: Andrew Morton , Masami Hiramatsu , Peter Zijlstra , Mike Rapoport , Alexander Potapenko , Randy Dunlap , Marco Elver , 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 v6 14/23] mm/ksw: resolve stack watch addr and len Date: Tue, 30 Sep 2025 10:43:35 +0800 Message-ID: <20250930024402.1043776-15-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250930024402.1043776-1-wangjinchao600@gmail.com> References: <20250930024402.1043776-1-wangjinchao600@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 829A9140002 X-Stat-Signature: g141qnhz356ozxaexmred5193kki14yw X-Rspam-User: X-HE-Tag: 1759200334-292750 X-HE-Meta: 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 dn6EK/Hx 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 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: Add helpers to find the stack canary or a local variable addr and len for the probed function based on ksw_get_config(). For canary search, limits search to a fixed number of steps to avoid scanning the entire stack. Validates that the computed address and length are within the kernel stack. Signed-off-by: Jinchao Wang --- mm/kstackwatch/stack.c | 77 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 74 insertions(+), 3 deletions(-) diff --git a/mm/kstackwatch/stack.c b/mm/kstackwatch/stack.c index e596ef97222d..3c4cb6d5b58a 100644 --- a/mm/kstackwatch/stack.c +++ b/mm/kstackwatch/stack.c @@ -9,6 +9,7 @@ #include "kstackwatch.h" +#define MAX_CANARY_SEARCH_STEPS 128 static struct kprobe entry_probe; static struct fprobe exit_probe; @@ -59,13 +60,83 @@ static bool ksw_stack_check_ctx(bool entry) return false; } +static unsigned long ksw_find_stack_canary_addr(struct pt_regs *regs) +{ + unsigned long *stack_ptr, *stack_end, *stack_base; + unsigned long expected_canary; + unsigned int i; + + stack_ptr = (unsigned long *)kernel_stack_pointer(regs); + + stack_base = (unsigned long *)(current->stack); + + // TODO: limit it to the current frame + stack_end = (unsigned long *)((char *)current->stack + THREAD_SIZE); + + expected_canary = current->stack_canary; + + if (stack_ptr < stack_base || stack_ptr >= stack_end) { + pr_err("Stack pointer 0x%lx out of bounds [0x%lx, 0x%lx)\n", + (unsigned long)stack_ptr, (unsigned long)stack_base, + (unsigned long)stack_end); + return 0; + } + + for (i = 0; i < MAX_CANARY_SEARCH_STEPS; i++) { + if (&stack_ptr[i] >= stack_end) + break; + + if (stack_ptr[i] == expected_canary) { + pr_debug("canary found i:%d 0x%lx\n", i, + (unsigned long)&stack_ptr[i]); + return (unsigned long)&stack_ptr[i]; + } + } + + pr_debug("canary not found in first %d steps\n", + MAX_CANARY_SEARCH_STEPS); + return 0; +} + +static int ksw_stack_validate_addr(unsigned long addr, size_t size) +{ + unsigned long stack_start, stack_end; + + if (!addr || !size) + return -EINVAL; + + stack_start = (unsigned long)current->stack; + stack_end = stack_start + THREAD_SIZE; + + if (addr < stack_start || (addr + size) > stack_end) + return -ERANGE; + + return 0; +} + static int ksw_stack_prepare_watch(struct pt_regs *regs, const struct ksw_config *config, ulong *watch_addr, u16 *watch_len) { - /* implement logic will be added in following patches */ - *watch_addr = 0; - *watch_len = 0; + ulong addr; + u16 len; + + // default is to watch the canary + if (!ksw_get_config()->watch_len) { + addr = ksw_find_stack_canary_addr(regs); + len = sizeof(ulong); + } else { + addr = kernel_stack_pointer(regs) + ksw_get_config()->sp_offset; + len = ksw_get_config()->watch_len; + } + + if (ksw_stack_validate_addr(addr, len)) { + pr_err("invalid stack addr:0x%lx len :%u\n", addr, len); + return -EINVAL; + } + + *watch_addr = addr; + *watch_len = len; return 0; } -- 2.43.0