From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23255C433F5 for ; Tue, 7 Sep 2021 14:14:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 06A6361101 for ; Tue, 7 Sep 2021 14:14:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237860AbhIGOPr (ORCPT ); Tue, 7 Sep 2021 10:15:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237150AbhIGOPR (ORCPT ); Tue, 7 Sep 2021 10:15:17 -0400 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3F42C0613C1 for ; Tue, 7 Sep 2021 07:14:08 -0700 (PDT) Received: by mail-qv1-xf49.google.com with SMTP id b8-20020a0562141148b02902f1474ce8b7so15177742qvt.20 for ; Tue, 07 Sep 2021 07:14:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ClauTO0DAc/W2CE5FaWJtasGRNKjOeQhVVw0fZ55opA=; b=ICdgop9Bb/UlNIicMIQWpjefBvU62X7yD2tARPBACjMMeNeFKwL6hpa4za3Q+GViph 59yYezR+3aidPQ4onhqjPPPGR4f/IJ0F0Lq2blaciGq800jLMrwOi6qn9Tr39ECNIEHI wpHPULsvIva0eZTmQLyc2Xu/kI8dANICLgD99thQF9/xwBQM453Fcpo01BqwkjaiJEc7 VW6igdwjJSIfWLdmnBMhQ/2AmmT/YbgKiSok59dlxnsL7bOq1G9Xf8FpiQS0SGrGT4sc IDimGSf/TGzEFVj2tZta1r7d+1QalLw3e4KnH938MLWkG9cgJiBntBlEk2MNKDx+r5/O XgnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ClauTO0DAc/W2CE5FaWJtasGRNKjOeQhVVw0fZ55opA=; b=GzP1WynBcHltzXwffZY7MMReSESt6HzCXtX39C9mewmYodwdse9c7rMg8NcexQkDrO f8AiOkyZhV06E5LnB6vNYAnQqFd7ugKmp9QQJQnT5XdAQrdQRTn5JcOMwExJj0VDMygi 2PIXKnH5Pzsr7tVtF00pGcbIEC6+rpITPThRUC/SNmqE0/3QfLAgu2VWDoxuVJLqgonp yWii5/94P35QsKNr7T4ODBl/5TlnRngYRu11tbAqWsERZlaHsLdzQcdp7zk+dR8nAMxi iJWnT6Iszv8YYqgb9nTDzpFMY58TdzT8mLEWhAoAyIo9QjbYAHnkCNM0poTAsegL0zv7 n44w== X-Gm-Message-State: AOAM531gtlGBNlp3ygvuoBt+gXF9r56SXeN8aUOgkpf5T2PhdbcQuUfZ ojoIWvZsjBndAk0mtMpOlRkELIhTnw== X-Google-Smtp-Source: ABdhPJw87QSuzKKPiaQWZq+ibYy/Wvgp6rb9RM4pXrZmwrnDnpMuaZQjS0f+oetPSFS2lDFVXSeJ2ZruVQ== X-Received: from elver.muc.corp.google.com ([2a00:79e0:15:13:6800:c1ea:4271:5898]) (user=elver job=sendgmr) by 2002:a05:6214:14f2:: with SMTP id k18mr17256135qvw.19.1631024048156; Tue, 07 Sep 2021 07:14:08 -0700 (PDT) Date: Tue, 7 Sep 2021 16:13:04 +0200 In-Reply-To: <20210907141307.1437816-1-elver@google.com> Message-Id: <20210907141307.1437816-4-elver@google.com> Mime-Version: 1.0 References: <20210907141307.1437816-1-elver@google.com> X-Mailer: git-send-email 2.33.0.153.gba50c8fa24-goog Subject: [PATCH 3/6] lib/stackdepot: introduce __stack_depot_save() From: Marco Elver To: elver@google.com Cc: Andrew Morton , Shuah Khan , Tejun Heo , Lai Jiangshan , Andrey Konovalov , Walter Wu , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Vijayanand Jitta , Vinayak Menon , "Gustavo A. R. Silva" , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Aleksandr Nogikh , Taras Madan Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add __stack_depot_save(), which provides more fine-grained control over stackdepot's memory allocation behaviour, in case stackdepot runs out of "stack slabs". Normally stackdepot uses alloc_pages() in case it runs out of space; passing can_alloc==false to __stack_depot_save() prohibits this, at the cost of more likely failure to record a stack trace. Signed-off-by: Marco Elver --- include/linux/stackdepot.h | 4 ++++ lib/stackdepot.c | 42 ++++++++++++++++++++++++++++++++------ 2 files changed, 40 insertions(+), 6 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 97b36dc53301..b2f7e7c6ba54 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -15,6 +15,10 @@ typedef u32 depot_stack_handle_t; +depot_stack_handle_t __stack_depot_save(unsigned long *entries, + unsigned int nr_entries, + gfp_t gfp_flags, bool can_alloc); + depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t gfp_flags); diff --git a/lib/stackdepot.c b/lib/stackdepot.c index c80a9f734253..cab6cf117290 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -248,17 +248,28 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, EXPORT_SYMBOL_GPL(stack_depot_fetch); /** - * stack_depot_save - Save a stack trace from an array + * __stack_depot_save - Save a stack trace from an array * * @entries: Pointer to storage array * @nr_entries: Size of the storage array * @alloc_flags: Allocation gfp flags + * @can_alloc: Allocate stack slabs (increased chance of failure if false) + * + * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is + * %true, is allowed to replenish the stack slab pool in case no space is left + * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids + * any allocations and will fail if no space is left to store the stack trace. + * + * Context: Any context, but setting @can_alloc to %false is required if + * alloc_pages() cannot be used from the current context. Currently + * this is the case from contexts where neither %GFP_ATOMIC nor + * %GFP_NOWAIT can be used (NMI, raw_spin_lock). * - * Return: The handle of the stack struct stored in depot + * Return: The handle of the stack struct stored in depot, 0 on failure. */ -depot_stack_handle_t stack_depot_save(unsigned long *entries, - unsigned int nr_entries, - gfp_t alloc_flags) +depot_stack_handle_t __stack_depot_save(unsigned long *entries, + unsigned int nr_entries, + gfp_t alloc_flags, bool can_alloc) { struct stack_record *found = NULL, **bucket; depot_stack_handle_t retval = 0; @@ -291,7 +302,7 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, * The smp_load_acquire() here pairs with smp_store_release() to * |next_slab_inited| in depot_alloc_stack() and init_stack_slab(). */ - if (unlikely(!smp_load_acquire(&next_slab_inited))) { + if (unlikely(can_alloc && !smp_load_acquire(&next_slab_inited))) { /* * Zero out zone modifiers, as we don't have specific zone * requirements. Keep the flags related to allocation in atomic @@ -339,6 +350,25 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, fast_exit: return retval; } +EXPORT_SYMBOL_GPL(__stack_depot_save); + +/** + * stack_depot_save - Save a stack trace from an array + * + * @entries: Pointer to storage array + * @nr_entries: Size of the storage array + * @alloc_flags: Allocation gfp flags + * + * Context: Contexts where allocations via alloc_pages() are allowed. + * + * Return: The handle of the stack struct stored in depot, 0 on failure. + */ +depot_stack_handle_t stack_depot_save(unsigned long *entries, + unsigned int nr_entries, + gfp_t alloc_flags) +{ + return __stack_depot_save(entries, nr_entries, alloc_flags, true); +} EXPORT_SYMBOL_GPL(stack_depot_save); static inline int in_irqentry_text(unsigned long ptr) -- 2.33.0.153.gba50c8fa24-goog