From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f172.google.com (mail-pf1-f172.google.com [209.85.210.172]) (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 5E5D52E92D6 for ; Fri, 12 Sep 2025 10:12:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757671959; cv=none; b=p4F4YL4zw1VnfdWzLY3Hwm1UNnuYL7OL80j7uKtgKW+xdDWcLL+iO3s4WmCQSjsH4oKlEEoIpQMhoYuzAqlZkCZni/QdFVxgYgjYfhocF0fKd3zXvytM+HWWCaoCUwoowF1bxxdiPcii+iL8BNsTekuVrnMJBeV+mOthK30hlV4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757671959; c=relaxed/simple; bh=i3v51fD9Nx/GpVeSYWAguecpXuWplCvYwMF4XBy55cA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OWtFLSIbn06yKFW3qe7GlzyeAz7jCrOWI7XkwYkXZX7JiittWSk6JsEBfTibmZ86MwCrhKJ/PXbTd+rQrHeVx18M91p2im7w4CiZoCoFXRWp0h/faAdfzUlafSGSSeKAPpewo5bBuNEeEZmUUGSSKgrsp43BGAh+m4ZuaO1dr2c= 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=F25Pgm/Y; arc=none smtp.client-ip=209.85.210.172 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="F25Pgm/Y" Received: by mail-pf1-f172.google.com with SMTP id d2e1a72fcca58-77287fb79d3so1483098b3a.1 for ; Fri, 12 Sep 2025 03:12:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1757671956; x=1758276756; darn=lists.linux.dev; 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=jBWUZGT7AQZjVN5sSaCPPhxiXndvcDbF8VJhhLu7a/o=; b=F25Pgm/YQcsbgDpolZPKJPdA+6fSqU3qLzoSis8Sh7EyUgoehNmYz1chHpqh0YLRZ+ QAM7kdMRBtWS+u6AAZC0uo4S4RIajraSQSrV1VsfQxZoSWvHZ7CTIOLRg4W5cunFDdOu ql8qgENXz0TruCm13xSwUGtbfOojO/gTQdkIp+YEK0768IBktqWVN/vnZmE+xj/sPAnu FiJ4UxIXDcsw9flAC8bcfBhLZVQH8SnXzdbe1A6Ha5EfLXa7mzZ/BhpgfEToSlWbyEeE iAdjNNj/uoYzJz4VF1aHeJ+sVOXJS6BcMMmiEVHMJL4bMaP/vOJW8Qxg8S7MIhLnZRk3 hIIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757671956; x=1758276756; 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=jBWUZGT7AQZjVN5sSaCPPhxiXndvcDbF8VJhhLu7a/o=; b=xIpVao9yyAk3fAdB/0Lh6IUhNV7p3Q110ze+yE/kQUSn7n7xI57V1mI4bu9dvte7W+ 2fxYvVorsJWEOC0FO1omjOP8sdiBfHCf9YhHcwrw6xDy7pljLona9f72Uxn4haYunb5y Eptz9j1MDhuxno06/QCq4p/773ntxy+rcoDh6Zm5zAo+Jb3tFeE1y0uve9KFj/nC9HOU R8fiB/T0Z5vtI5zwgl+joUyCPeUE+Zl0Q39b91VBl0jARo4CZ99oCABjFc/XGn4RqRLr +vZWFsNF4fO172OjePbtbREUv0Znh7dknzSW/tVTCBpzBc9BXO6wZtUeP+4p0gwo+8mO C31g== X-Forwarded-Encrypted: i=1; AJvYcCWwO0U67MaTBXIcpWSgyyMUIWOHoBBEKBB9AWjqrh4LoMP2F29zo0I93hffWjoLo+CkqXxK@lists.linux.dev X-Gm-Message-State: AOJu0YxjRMKzXAXAHv0nImnKoAKWB8/mDdUuseNrXkUr62aQpiXOXBRC OwyhSbR5ozGvf1M/UQY3GVMKpZ0AerAxkG2/i0mI1ciwEQlo7JtDrEht X-Gm-Gg: ASbGncuTDnFhSqfHJcPVuqV5lMGPum7zS/uN3aJXcb4yNxeW3v8MyL0X2GUtppeYOCf gcke5OMjGl7Ywj3o8px1yZNhAIMPr9/WY2EGEf1PGa1nWMcZ7pqJIG0AaU6Is57dup7Rn3FSFfP +qDN52GNdB/VuCb6TUaThr93a5jzL+lLkQNBnY+2y8p/C8uTt8zmg9NT3W6LJf/W100R0nmZWWP R6frFLnxZLKj6YjNGpkc8JMGC+wqBp4Wc3z4tIfAMZGnZnJeVNCfn0pVdgGBi8OXXfd5lOWv6ar ZmDGzTBIiltNRRcL4GGQrDKW/DwXZ3MzpJTv5FJ06hmoM4r/jXAisKLmJDFmbmyL6Nc34XF2Dx3 D2JK7+fcdi/Hp0IoWKL7o0GdiQhz4uyJFXM8q+v0Z+Fob5m8dsQ== X-Google-Smtp-Source: AGHT+IE0smHKx/fxxESUMD26AxoS7YeR+pzOUZ9t8bbqYrL6zePDghHY9Bjvt2Dlrnb+iBu56FBUDg== X-Received: by 2002:a17:903:3c4d:b0:24c:cc2c:9da9 with SMTP id d9443c01a7336-25d24bb3201mr28288785ad.14.1757671956234; Fri, 12 Sep 2025 03:12:36 -0700 (PDT) Received: from localhost ([185.49.34.62]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-25c3b307073sm44099805ad.144.2025.09.12.03.12.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Sep 2025 03:12:35 -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 08/21] mm/ksw: Add atomic ksw_watch_on() and ksw_watch_off() Date: Fri, 12 Sep 2025 18:11:18 +0800 Message-ID: <20250912101145.465708-9-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: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The atomic_long_cmpxchg() ensures at most one active watchpoint exists at any time, with ksw_watch_on() succeeding only when no watch is active (current address is placeholder) and ksw_watch_off() succeeding only when the caller knows the active watch address. For cross-CPU synchronization, updates are propagated using direct modification on the local CPU and asynchronous IPIs for remote CPUs. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 2 + mm/kstackwatch/watch.c | 73 +++++++++++++++++++++++++++++++++++- 2 files changed, 74 insertions(+), 1 deletion(-) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index 3ea191370970..0786fa961011 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -41,5 +41,7 @@ const struct ksw_config *ksw_get_config(void); /* watch management */ int ksw_watch_init(void); void ksw_watch_exit(void); +int ksw_watch_on(ulong watch_addr, u16 watch_len); +int ksw_watch_off(ulong watch_addr, u16 watch_len); #endif /* _KSTACKWATCH_H */ diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index d3399ac840b2..14549e02faf1 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 @@ -9,10 +10,16 @@ static struct perf_event *__percpu *watch_events; -static unsigned long watch_holder; +static ulong watch_holder; +static atomic_long_t watched_addr = ATOMIC_LONG_INIT((ulong)&watch_holder); static struct perf_event_attr watch_attr; +static void ksw_watch_on_local_cpu(void *info); + +static DEFINE_PER_CPU(call_single_data_t, + watch_csd) = CSD_INIT(ksw_watch_on_local_cpu, NULL); + bool panic_on_catch; module_param(panic_on_catch, bool, 0644); MODULE_PARM_DESC(panic_on_catch, "panic immediately on corruption catch"); @@ -29,6 +36,70 @@ static void ksw_watch_handler(struct perf_event *bp, panic("Stack corruption detected"); } +static void ksw_watch_on_local_cpu(void *data) +{ + struct perf_event *bp; + ulong flags; + int cpu; + int ret; + + local_irq_save(flags); + cpu = raw_smp_processor_id(); + bp = *per_cpu_ptr(watch_events, cpu); + if (!bp) { + local_irq_restore(flags); + return; + } + + ret = modify_wide_hw_breakpoint_local(bp, &watch_attr); + local_irq_restore(flags); + + if (ret) { + pr_err("failed to reinstall HWBP on CPU %d ret %d\n", cpu, + ret); + return; + } +} + +static void __ksw_watch_target(ulong addr, u16 len) +{ + int cpu; + call_single_data_t *csd; + + watch_attr.bp_addr = addr; + watch_attr.bp_len = len; + + /* ensure watchpoint update is visible to other CPUs before IPI */ + smp_wmb(); + + for_each_online_cpu(cpu) { + if (cpu == raw_smp_processor_id()) { + ksw_watch_on_local_cpu(NULL); + } else { + csd = &per_cpu(watch_csd, cpu); + smp_call_function_single_async(cpu, csd); + } + } +} + +static int ksw_watch_target(ulong old_addr, ulong new_addr, u16 watch_len) +{ + if (atomic_long_cmpxchg(&watched_addr, old_addr, new_addr) != old_addr) + return -EINVAL; + __ksw_watch_target(new_addr, watch_len); + return 0; +} + +int ksw_watch_on(ulong watch_addr, u16 watch_len) +{ + return ksw_watch_target((ulong)&watch_holder, watch_addr, watch_len); +} + +int ksw_watch_off(ulong watch_addr, u16 watch_len) +{ + return ksw_watch_target(watch_addr, (ulong)&watch_holder, watch_len); +} + int ksw_watch_init(void) { int ret; -- 2.43.0