From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f173.google.com (mail-pf1-f173.google.com [209.85.210.173]) (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 0C6BF258CE5 for ; Tue, 30 Sep 2025 02:45:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759200331; cv=none; b=B3g80c568VTwMwzq9F8T0eAEfS1ci+Jpws/mkisaEU1XIyO7nM6Tae4YGcjzuE/Avw5pRFr6bXZaPycnDDomWcWiYBkm+R4Jw1/pnYsyAkFgVEfhz17BLcXHKL6gHWPwdMgjkDJVwN3FxjwEzfSUQwcboYSiFDEWtRoYhOZ/gJY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759200331; c=relaxed/simple; bh=Sl2YI7Td/C9YkkJpnWkOlkyn4hvpDBvdNr6f7stAoSw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cdcZ63hNGDXAa+iIiHkAY8Wh23DpfIBgZtWGqmBkdmzC7YGMLlfY5U3aVIaC3g5XFWeoDWX2sSINBmOywLpzc8VqcZZ5xLw7tnOs8Mgs3Brbg2+6NmivXfUugjpbFaUy/NfvPui2Gx82loLHJGmcr9u8LdhISEceU6QPJ04Jl/Q= 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=aiyBF/wn; arc=none smtp.client-ip=209.85.210.173 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="aiyBF/wn" Received: by mail-pf1-f173.google.com with SMTP id d2e1a72fcca58-782a77b5ec7so1927907b3a.1 for ; Mon, 29 Sep 2025 19:45:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1759200329; x=1759805129; 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=sX4DcHmKN6k6jLli4BcDyPNAsEAGb3ORwL+dRbW7euA=; b=aiyBF/wnrDTAEUGQ3gs3hkoDo6ov65uut92C3I+ngMReOiufaQ1vmTFIu1XnSWaGGh khX0pjDWJadRCDMCM3CMXPMKCKltjKWNUtc51qshE5kXFvc287XTIF8QXgev3XVGSn9y 05DxNPfZbgEUDZkoFxdl+YdQopelHsQzG3KhzdyKhxkrnE1Hv/+FHU7/2n9zyeLmIYVz uTo47nYJvcaZwtoT0ajVuJE7PlG/Oh+U/sm85SO4tUaIx1F5/CrTTe7S+qGifdVeBf89 wV/OxahguZKjvN/XTCzxgnwE0taEPgzJ1LSh95A9Ols1FTzW4QPkrMnIoSn1CJaDFPvk oNiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759200329; x=1759805129; 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=sX4DcHmKN6k6jLli4BcDyPNAsEAGb3ORwL+dRbW7euA=; b=nQ2sNpIDUZ5z/AV7tPFbalwmdyoIBvaxNAAdkUpNvLq2D2+8D001z13pWvl/MPJYHQ b0aSiFOB3q642EWBXo674bWzWwJ9NRAhRWpiBHTtAJBNmM3X4/FQWiLamsHJasGoC+EM UF+CjSPILB/aAWiwB2bCMo1gfOVV2ZaozVlRU/e3znIKqXB8c74Cso4rym9mzkyiiyj7 8SWnOq80VcCT9fpCnCG2wlM0CH+UeK6wA37HZh8XxcY8wbC21GMZK6b4siJCjrK6U4yR QTCie9Mt2/ZTFM55PZWCIVrfyUqW0q1hFkHigdrSvAm7wxsD72OCWa7sjW449DN3xmnm ZX1g== X-Forwarded-Encrypted: i=1; AJvYcCU7jrm7xaPpKQtNEzCF1C4DkKFzzCAXG/c+GLZOWtwjy3LpYkwurpm6p9WDDSkswQ+AAZC8zw+vCKg=@vger.kernel.org X-Gm-Message-State: AOJu0YyyiGYvW6ToxI2EFsOJ2Al7+AJ7vjT8gpZlZvtRZfekfF71Xb8U U4bnOT4ZHb9Qtl+jbPW+7cINZAwjBqb5ReHlz/2myKFcpLNTteQFToxb X-Gm-Gg: ASbGncs+rKq+efkGHmLle5XUauec4fKln6LNK42xN7uarxncOAaDezWH7t9g+fFW0GG pwzSD9J8ckLuBWAfpXGV0rQ4wqp2G/Nmzq3Z7TUURMdwrbyGfoOFxV0YMWD4Yhud97y04MIQel6 yHq5YHDzY5qdtN+ani7jDwNU2vFsH1/JrowRY6iXTg4sv9wYID7mhrAeptdr8VZJ3oz1DIj7aIn p+6titaJyV5ugd9MWrj9woCzTUZO+DUX7IzVYj9EUhfoXnT/lx5hJvhBhoPUP50gE+v14Nlhflz +Mix58IMJv2IJjKJHJOYvDl/zhuK9r56aM9p2f1YeKjqL5DBervuBw7ImG6mGzcsARfjRNNH29k 24vBKq0HiJtKsccQoiPtov5v8xZkQF0J9/ppB0Xm00bLkEpOB3YzEY3ktg0FY9GQNffafCJv7JI pkyuS08LlmFjI= X-Google-Smtp-Source: AGHT+IGTqTwXopd2ojQqxBEBkqI1vY+O5jS9ODQlBJjx1qTPcUYlj9RqM72R3p1od6/UyekDO+cXWA== X-Received: by 2002:a05:6a00:b53:b0:76e:885a:c332 with SMTP id d2e1a72fcca58-780fcf080d2mr23371738b3a.32.1759200329155; Mon, 29 Sep 2025 19:45:29 -0700 (PDT) Received: from localhost ([45.142.167.196]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-782e36c803fsm5830819b3a.38.2025.09.29.19.45.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Sep 2025 19:45:28 -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 13/23] mm/ksw: add per-task ctx tracking Date: Tue, 30 Sep 2025 10:43:34 +0800 Message-ID: <20250930024402.1043776-14-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> Precedence: bulk X-Mailing-List: workflows@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Each task tracks its depth, stack pointer, and generation. A watchpoint is enabled only when the configured depth is reached, and disabled on function exit. The context is reset when probes are disabled, generation changes, or exit depth becomes inconsistent. Duplicate arming on the same frame is skipped. Signed-off-by: Jinchao Wang --- mm/kstackwatch/stack.c | 67 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) diff --git a/mm/kstackwatch/stack.c b/mm/kstackwatch/stack.c index 9f59f41d954c..e596ef97222d 100644 --- a/mm/kstackwatch/stack.c +++ b/mm/kstackwatch/stack.c @@ -12,6 +12,53 @@ static struct kprobe entry_probe; static struct fprobe exit_probe; +static bool probe_enable; +static u16 probe_generation; + +static void ksw_reset_ctx(void) +{ + struct ksw_ctx *ctx = ¤t->ksw_ctx; + + if (ctx->wp) + ksw_watch_off(ctx->wp); + + ctx->wp = NULL; + ctx->sp = 0; + ctx->depth = 0; + ctx->generation = READ_ONCE(probe_generation); +} + +static bool ksw_stack_check_ctx(bool entry) +{ + struct ksw_ctx *ctx = ¤t->ksw_ctx; + u16 cur_enable = READ_ONCE(probe_enable); + u16 cur_generation = READ_ONCE(probe_generation); + u16 cur_depth, target_depth = ksw_get_config()->depth; + + if (!cur_enable) { + ksw_reset_ctx(); + return false; + } + + if (ctx->generation != cur_generation) + ksw_reset_ctx(); + + if (!entry && !ctx->depth) { + ksw_reset_ctx(); + return false; + } + + if (entry) + cur_depth = ctx->depth++; + else + cur_depth = --ctx->depth; + + if (cur_depth == target_depth) + return true; + else + return false; +} + static int ksw_stack_prepare_watch(struct pt_regs *regs, const struct ksw_config *config, ulong *watch_addr, u16 *watch_len) @@ -26,10 +73,22 @@ static void ksw_stack_entry_handler(struct kprobe *p, struct pt_regs *regs, unsigned long flags) { struct ksw_ctx *ctx = ¤t->ksw_ctx; + ulong stack_pointer; ulong watch_addr; u16 watch_len; int ret; + stack_pointer = kernel_stack_pointer(regs); + + /* + * triggered more than once, may be in a loop + */ + if (ctx->wp && ctx->sp == stack_pointer) + return; + + if (!ksw_stack_check_ctx(true)) + return; + ret = ksw_watch_get(&ctx->wp); if (ret) return; @@ -50,6 +109,7 @@ static void ksw_stack_entry_handler(struct kprobe *p, struct pt_regs *regs, return; } + ctx->sp = stack_pointer; } static void ksw_stack_exit_handler(struct fprobe *fp, unsigned long ip, @@ -58,6 +118,8 @@ static void ksw_stack_exit_handler(struct fprobe *fp, unsigned long ip, { struct ksw_ctx *ctx = ¤t->ksw_ctx; + if (!ksw_stack_check_ctx(false)) + return; if (ctx->wp) { ksw_watch_off(ctx->wp); @@ -92,11 +154,16 @@ int ksw_stack_init(void) return ret; } + WRITE_ONCE(probe_generation, READ_ONCE(probe_generation) + 1); + WRITE_ONCE(probe_enable, true); + return 0; } void ksw_stack_exit(void) { + WRITE_ONCE(probe_enable, false); + WRITE_ONCE(probe_generation, READ_ONCE(probe_generation) + 1); unregister_fprobe(&exit_probe); unregister_kprobe(&entry_probe); } -- 2.43.0