From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f46.google.com (mail-pj1-f46.google.com [209.85.216.46]) (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 282E52E7648 for ; Thu, 9 Oct 2025 10:57:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760007466; cv=none; b=quCI8QRjIUDvOCWE7qczeVcC5A+zruc3f8DBquAjX+z7ujCV31sCBpZDk89FFm9qnWWs3e8URqIWPdKGGukhsodv+IQNC5W7mWYlrxTvi1PTsnUnthGokxtTjGeVGxkVA+y23fFFxE5ufwedXKJYxwJO/IKyKgDOclYzA9hkSI0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760007466; c=relaxed/simple; bh=0RaB9b3mDxARpzNAU+b9+OM/53UguV9OX02ut00avNs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WBHYFfURQ9SrAH6gu5l1+PeiNsTgHXF2rPAKgfADKwrMOkH4RCYNvyaRsys9MPGsz0tfe+xrw7C65COBXzCBf4m7ZzYYi/zr/tCxosP4uYuhRGv6s6DXIhsO+7YaOmboKj68+3q5eDBowEkkgVGnCd2YCSdC3VZdR5qdEcaLaj0= 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=A/5C61gR; arc=none smtp.client-ip=209.85.216.46 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="A/5C61gR" Received: by mail-pj1-f46.google.com with SMTP id 98e67ed59e1d1-3381f041d7fso2157514a91.0 for ; Thu, 09 Oct 2025 03:57:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1760007463; x=1760612263; 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=8p2Xfne7CGpLjN/MkaU3Ee28S3aCNgQ2oxnJpFebIbs=; b=A/5C61gRN5+BtVe0oAtzwEP551cuqM59naP4sL5MXsMQCW4ngR811ENWiTChuESkq9 AKKX349RReYymf1WXkgbqaDRoo9YK9Qs3AVvTQ7RTwLwv/1jMMUWfDxhByVdS0XWWyd2 Dck+cQ8kxIYa8GE3J5yQhPzuN10gaO6HMeKK1vB1zROXfjEvPqClPc0mEFusJYSvGPoL /bUvnZGxuAro6Uyfed39BMglJFBEKKbB9umLgImQGGmHpaMHIAJ9Qe9jVI2MWuk6DHh1 fAP390fwSUMADEQympYscpO13ucL5iil1xi3uWMEr+5N8bGOeNuBfP4MAFwN5v4f/RS5 0pOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760007463; x=1760612263; 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=8p2Xfne7CGpLjN/MkaU3Ee28S3aCNgQ2oxnJpFebIbs=; b=EH+GtBMuDOeB5yP4I3+6aJXJ/Sb/8spVhN5EUuvWTBKdvPCVlGySWjPv1F7C0vkU89 OaewetuPDRxuffwOvU7Vcy4OIA1gkCU3tQyUMkvQgcX5UigA0qrgwFWPI+imE7hUsQ9L 3dBFIdC5GhEtGyzJMqvS9QD1uBX0qKdrgpL8kkl06AjLgUIbjoDGSPZ5biz8dqBZbAUp d3+En8+vcBXSbirZeI3rZJmC+9r7J3xr+v/t5Jh/05Qf6VvQsdEyqntalIaEzVpoKm85 M388EXJx4oR9XGW1L625N+gnC7fGqz+YAvFPY0S37WyeYUbNjxSX3eW0xWaDt7K5ibi7 NgPQ== X-Forwarded-Encrypted: i=1; AJvYcCWW9yftFqYBwWhCGJzwKY1eeFjrSlX5KhgCtKj9MkO+CMJhJKf2Aw4GX9dBg89u9bV5tQEcwOUnT2s=@vger.kernel.org X-Gm-Message-State: AOJu0Yw8f6jfOAZesqkyZTpHrPPEmF4UFL0z1wphVCRAA4H+yzOGp+Ck joyV0IFKQIup7ukCRav2Hhc3tkJvJvKfEs48Q95cnhPV7KPR3AMSinml X-Gm-Gg: ASbGncsqBvJhJB/y1NcIymWn1RK820AVwoCiIYor9J7nkD5vmc5f/4+88eH9n2IIqfM D76a7NBWgqTBg8KwTcIjls/3BDM4pC9VjxJ2SIRF9UNtjUAIs84sxDOV+WUoZmAP5xQA/XctGuw eBDCRS/R0DnX/2TmTAUDDLms/9tFgGiQCKxmhAvmtfzD+gKD2PYTQs7vd4uVGqv/Cx0+udarKYe 7XqRBgFNdVVylW+HwWLTgDMdIPdZv2RxXQudY5R0YDbPnOoZLyOb0Q5sLzUjcEvuaRd3LmZ1VfN quHnvE4h3DfHSz/G15lnJozgmD2v8frSKlJqKhEx9Rc1KZeWDV8EGpEF1YbhxkWmRrTTQbN7/Q2 aXej16ozyrmgvWFkRq4XcTBacRNlfKGFFN8dvYpoPdfjP87wP9WXFQkYlyB/8 X-Google-Smtp-Source: AGHT+IGh87PYrVHyXpdGI3lpiqctQ3hOQgwGz+QU0SKFptl527HtAxTN0ZxVB5GZOA/u2hsAdulJlA== X-Received: by 2002:a17:90b:3e83:b0:32e:23c9:6f41 with SMTP id 98e67ed59e1d1-33b51676ef2mr8250254a91.5.1760007463200; Thu, 09 Oct 2025 03:57:43 -0700 (PDT) Received: from localhost ([45.142.165.62]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-33b52a4f8bfsm2196325a91.10.2025.10.09.03.57.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Oct 2025 03:57:42 -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 v7 09/23] mm/ksw: ignore false positives from exit trampolines Date: Thu, 9 Oct 2025 18:55:45 +0800 Message-ID: <20251009105650.168917-10-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251009105650.168917-1-wangjinchao600@gmail.com> References: <20251009105650.168917-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: workflows@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Because trampolines run after the watched function returns but before the exit_handler is called, and in the original stack frame, so the trampoline code may overwrite the watched stack address. These false positives should be ignored. is_ftrace_trampoline() does not cover all trampolines, so add a local check to handle the remaining cases. Signed-off-by: Jinchao Wang --- mm/kstackwatch/watch.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index 887cc13292dc..722ffd9fda7c 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -2,6 +2,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include +#include #include #include #include @@ -18,10 +19,46 @@ bool panic_on_catch; module_param(panic_on_catch, bool, 0644); MODULE_PARM_DESC(panic_on_catch, "panic immediately on corruption catch"); +#define TRAMPOLINE_NAME "return_to_handler" +#define TRAMPOLINE_DEPTH 16 + +/* Resolved once, then reused */ +static unsigned long tramp_start, tramp_end; + +static void ksw_watch_resolve_trampoline(void) +{ + unsigned long sz, off; + + if (likely(tramp_start && tramp_end)) + return; + + tramp_start = kallsyms_lookup_name(TRAMPOLINE_NAME); + if (tramp_start && kallsyms_lookup_size_offset(tramp_start, &sz, &off)) + tramp_end = tramp_start + sz; +} + +static bool ksw_watch_in_trampoline(unsigned long ip) +{ + if (tramp_start && tramp_end && ip >= tramp_start && ip < tramp_end) + return true; + return false; +} static void ksw_watch_handler(struct perf_event *bp, struct perf_sample_data *data, struct pt_regs *regs) { + unsigned long entries[TRAMPOLINE_DEPTH]; + int i, nr = 0; + + nr = stack_trace_save_regs(regs, entries, TRAMPOLINE_DEPTH, 0); + for (i = 0; i < nr; i++) { + //ignore trampoline + if (is_ftrace_trampoline(entries[i])) + return; + if (ksw_watch_in_trampoline(entries[i])) + return; + } + pr_err("========== KStackWatch: Caught stack corruption =======\n"); pr_err("config %s\n", ksw_get_config()->user_input); dump_stack(); @@ -168,6 +205,7 @@ int ksw_watch_init(void) { int ret; + ksw_watch_resolve_trampoline(); ret = ksw_watch_alloc(); if (ret <= 0) return -EBUSY; -- 2.43.0