From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (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 C7EE02E7F11 for ; Thu, 9 Oct 2025 10:57:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760007469; cv=none; b=G4AE/SQFNOgwG8WuQgvqtYNokmGqZICJlflDJxF4PAFBfJpxfVcsCdN0nITPxlIsR0hSH1RQbJs1hkvmvhKNsf2Zpgt5DdnBJpC5LPAzwRHlnDrsv9DV33WMFZPFYgsOZk7PclSaF+gQkAdKCCFu/61m8DAz8R29btEr4Dp75oM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760007469; c=relaxed/simple; bh=EtuMaKP8CWfi9pjY9FcQGV9HEHi4WtiOKMPT566R1T4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Zsb8FuXDgjaUvSEWqBqheHfouv+UyAiQCYVcppg+WZat6SUb2j7qbULgDmRtR2TC52fVNsvEBA6LSPsdG/Cy72ffUUPe54RwZ+SxKB7HEKW2+Au3R1FuQ66Xb1++iotXPigw956K4Iq6ZD4MSCxpvtjFC30cE5QMoTzZySQd6hc= 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=XRI7WsQw; arc=none smtp.client-ip=209.85.214.172 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="XRI7WsQw" Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-2698384978dso5869405ad.0 for ; Thu, 09 Oct 2025 03:57:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1760007467; x=1760612267; 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=VplC5p74+BCL3Xjzqw2UL/AL1hevTQUKrGPaYOT40mY=; b=XRI7WsQwvZLRMKH5k/2XVLyYjc1kYwTmbZQzTQs8ddME9gWi62JTPN0mJ4Wk7gzncb H36oPPlE+4GhxeIVK5rg5OyWOuAkOI0zpWmNs014z4plCAHGhaGjth1J/9DG2TAE+d6S 6QOYykAuyE24tlsPs2LNsEwEUMpiBs/KZSaR/akb+NiU0MbV38ySbdtbttfHv54v+JX6 /jBM440MshBnrVW+Rlk0KneqVWtUtWPbi8/fk6RwvI86WWBDD78jDfGzYZE8s4Eu2ZVK beZZi3L58M1MOPyDcrgQyViZfFIFoUSrKQWPOLkFARHotNXzR1lzfmB+MF7HQXsqA7ey AKcQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760007467; x=1760612267; 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=VplC5p74+BCL3Xjzqw2UL/AL1hevTQUKrGPaYOT40mY=; b=Khh+Uiuf32WHL10xpbjE4wxGnzZbLHXjq5i9D0a3a8eke6OyEHRx0CUWQ0kvoZVI/A +NLDBNCtMRwwWH23rwlDsGpnluTLR2mBb9/da2/4qOiNaR0eAPHAf9vq0gk7yiqw9ocK 01AzH5HiztmhZOhsg1M/UHaZrAc79i13bUdwiuzZ7M1QmMUxqM1MQDVMWQt3SirB/RcA Ux6JdK/cgJw842kuKVfyy31WTJFBgs/HZG6StI5x55lD6hxjaj2yo+mSl/KeLli49fxB xerVHcYy08Dfy0wYynE7Ubwu3QzC8XOoVV0nmMxkDq94YcncuMM52I3NvMrEnZ2V7dnz rwOg== X-Forwarded-Encrypted: i=1; AJvYcCW/eqERNnPWY2HgU1+NCick2y0QVl0+/gtmFw/WN781dsUq2LEj+fGPudUHJGb4gqNT5EMNl+ANkkk=@vger.kernel.org X-Gm-Message-State: AOJu0Ywn4VSKAvNnqcCvUTuh5TRKQK/GiaFu6lyFOqqpEf6dWGiMsLL7 VbIjVY0Ia/f5EuFb6u0uEqM2ZhNBZ4sSVqIbScvSGdZqZgFsSpV6rN8K X-Gm-Gg: ASbGnctWe93mjiRLftGKYzibTHMogJ5HtkvsAxqoX/6JAqyQBw3ceBRy++id6xD11HV tH836LH6/T0ItKMzElgzIq7zkJnl7d15ooKfIrL1+4x7pv2XNMtXjTcPBiuEE7m0BrQZex9dyFL AiFV6eeMpNtwd97+bxfQt4dpLll7ajhbkui/KircjVbVc3wTkni2TwjP4XvsXkz3DhqKyvif3ji ONqMmz7CrQSIRIMOZl9aieA9O4pTAaEgy8Sa229GaIhIji/ko7+e3ClNlc1qjvTSguwl7iQOUAE tEWTQnfcL+lgXsPX4EOwdoiaodXciqGX37cltP9OeriUcUy01327WN3e1TmWQBqIz7DbhEoq5VP bLSzlLUwZ9Ra5OrCK/ZdaWRwnvAC7V0jjMf57ZsrohQcn1fbeu2izP77o6XFX X-Google-Smtp-Source: AGHT+IHmVcOaWg336t/VgG0OW//aKmE7YjCOwXVIZ1hlLa92YU9803QfIvNvqjBNePbfTO+flKLHUg== X-Received: by 2002:a17:903:2342:b0:28d:1815:6382 with SMTP id d9443c01a7336-290272e3ed2mr91929215ad.46.1760007466971; Thu, 09 Oct 2025 03:57:46 -0700 (PDT) Received: from localhost ([45.142.165.62]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-33b5137dfa9sm6632975a91.15.2025.10.09.03.57.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Oct 2025 03:57:46 -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 10/23] mm/ksw: support CPU hotplug Date: Thu, 9 Oct 2025 18:55:46 +0800 Message-ID: <20251009105650.168917-11-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: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Register CPU online/offline callbacks via cpuhp_setup_state_nocalls() so stack watches are installed/removed dynamically as CPUs come online or go offline. When a new CPU comes online, register a hardware breakpoint for the holder, avoiding races with watch_on()/watch_off() that may run on another CPU. The watch address will be updated the next time watch_on() is called. Signed-off-by: Jinchao Wang --- mm/kstackwatch/watch.c | 52 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index 722ffd9fda7c..f32b1e46168c 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -89,6 +89,48 @@ static void ksw_watch_on_local_cpu(void *info) WARN(ret, "fail to reinstall HWBP on CPU%d ret %d", cpu, ret); } +static int ksw_watch_cpu_online(unsigned int cpu) +{ + struct perf_event_attr attr; + struct ksw_watchpoint *wp; + call_single_data_t *csd; + struct perf_event *bp; + + mutex_lock(&all_wp_mutex); + list_for_each_entry(wp, &all_wp_list, list) { + attr = wp->attr; + attr.bp_addr = (u64)&holder; + bp = perf_event_create_kernel_counter(&attr, cpu, NULL, + ksw_watch_handler, wp); + if (IS_ERR(bp)) { + pr_warn("%s failed to create watch on CPU %d: %ld\n", + __func__, cpu, PTR_ERR(bp)); + continue; + } + + per_cpu(*wp->event, cpu) = bp; + csd = per_cpu_ptr(wp->csd, cpu); + INIT_CSD(csd, ksw_watch_on_local_cpu, wp); + } + mutex_unlock(&all_wp_mutex); + return 0; +} + +static int ksw_watch_cpu_offline(unsigned int cpu) +{ + struct ksw_watchpoint *wp; + struct perf_event *bp; + + mutex_lock(&all_wp_mutex); + list_for_each_entry(wp, &all_wp_list, list) { + bp = per_cpu(*wp->event, cpu); + if (bp) + unregister_hw_breakpoint(bp); + } + mutex_unlock(&all_wp_mutex); + return 0; +} + static void ksw_watch_update(struct ksw_watchpoint *wp, ulong addr, u16 len) { call_single_data_t *csd; @@ -210,6 +252,16 @@ int ksw_watch_init(void) if (ret <= 0) return -EBUSY; + ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, + "kstackwatch:online", + ksw_watch_cpu_online, + ksw_watch_cpu_offline); + if (ret < 0) { + ksw_watch_free(); + pr_err("Failed to register CPU hotplug notifier\n"); + return ret; + } + return 0; } -- 2.43.0