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[2620:137:e000::1:20]) by mx.google.com with ESMTP id hk1-20020a17090b224100b002199a16366csi1716723pjb.173.2023.02.10.13.18.18; Fri, 10 Feb 2023 13:18:30 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.dev header.s=key1 header.b=NMUMtEuq; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.dev Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233917AbjBJVQ1 (ORCPT + 99 others); Fri, 10 Feb 2023 16:16:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232740AbjBJVQP (ORCPT ); Fri, 10 Feb 2023 16:16:15 -0500 Received: from out-125.mta0.migadu.com (out-125.mta0.migadu.com [91.218.175.125]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49C257537E for ; Fri, 10 Feb 2023 13:16:14 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1676063772; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=b3Y1ZbtnHRjNaHONV9sUdyWjn+clMFk+2c4Skh5NOGM=; b=NMUMtEuqwG0vlR2vqyaN6nCSOlFMRLLh2rBnX4ez3xSLDuXFeviXMGAoN1X/Gw8TaR2kMk vtoOxPtdDghv1NP+wPb2bGmxgUWe7yTaTqOfl3aWDVxPWgAJOi9o7DnwQMwnwQ9VH1Oy9s +feNTY56vXN778kgFVfIUPPpUMerwac= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko Cc: Andrey Konovalov , Vlastimil Babka , kasan-dev@googlegroups.com, Evgenii Stepanov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v2 05/18] lib/stackdepot: annotate init and early init functions Date: Fri, 10 Feb 2023 22:15:53 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1757480391669373008?= X-GMAIL-MSGID: =?utf-8?q?1757480391669373008?= From: Andrey Konovalov Add comments to stack_depot_early_init and stack_depot_init to explain certain parts of their implementation. Also add a pr_info message to stack_depot_early_init similar to the one in stack_depot_init. Also move the scale variable in stack_depot_init to the scope where it is being used. Reviewed-by: Alexander Potapenko Signed-off-by: Andrey Konovalov --- lib/stackdepot.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 202e07c4f02d..9fab711e4826 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -115,24 +115,34 @@ void __init stack_depot_request_early_init(void) __stack_depot_early_init_requested = true; } +/* Allocates a hash table via memblock. Can only be used during early boot. */ int __init stack_depot_early_init(void) { unsigned long entries = 0; - /* This is supposed to be called only once, from mm_init() */ + /* This function must be called only once, from mm_init(). */ if (WARN_ON(__stack_depot_early_init_passed)) return 0; - __stack_depot_early_init_passed = true; + /* + * If KASAN is enabled, use the maximum order: KASAN is frequently used + * in fuzzing scenarios, which leads to a large number of different + * stack traces being stored in stack depot. + */ if (kasan_enabled() && !stack_hash_order) stack_hash_order = STACK_HASH_ORDER_MAX; if (!__stack_depot_early_init_requested || stack_depot_disabled) return 0; + /* + * If stack_hash_order is not set, leave entries as 0 to rely on the + * automatic calculations performed by alloc_large_system_hash. + */ if (stack_hash_order) - entries = 1UL << stack_hash_order; + entries = 1UL << stack_hash_order; + pr_info("allocating hash table via alloc_large_system_hash\n"); stack_table = alloc_large_system_hash("stackdepot", sizeof(struct stack_record *), entries, @@ -142,7 +152,6 @@ int __init stack_depot_early_init(void) &stack_hash_mask, 1UL << STACK_HASH_ORDER_MIN, 1UL << STACK_HASH_ORDER_MAX); - if (!stack_table) { pr_err("hash table allocation failed, disabling\n"); stack_depot_disabled = true; @@ -152,6 +161,7 @@ int __init stack_depot_early_init(void) return 0; } +/* Allocates a hash table via kvcalloc. Can be used after boot. */ int stack_depot_init(void) { static DEFINE_MUTEX(stack_depot_init_mutex); @@ -160,11 +170,16 @@ int stack_depot_init(void) mutex_lock(&stack_depot_init_mutex); if (!stack_depot_disabled && !stack_table) { unsigned long entries; - int scale = STACK_HASH_SCALE; + /* + * Similarly to stack_depot_early_init, use stack_hash_order + * if assigned, and rely on automatic scaling otherwise. + */ if (stack_hash_order) { entries = 1UL << stack_hash_order; } else { + int scale = STACK_HASH_SCALE; + entries = nr_free_buffer_pages(); entries = roundup_pow_of_two(entries); @@ -179,7 +194,7 @@ int stack_depot_init(void) if (entries > 1UL << STACK_HASH_ORDER_MAX) entries = 1UL << STACK_HASH_ORDER_MAX; - pr_info("allocating hash table of %lu entries with kvcalloc\n", + pr_info("allocating hash table of %lu entries via kvcalloc\n", entries); stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL); if (!stack_table) {