From patchwork Mon Dec 11 03:12:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 176441 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:bcd1:0:b0:403:3b70:6f57 with SMTP id r17csp6807842vqy; Sun, 10 Dec 2023 19:13:00 -0800 (PST) X-Google-Smtp-Source: AGHT+IFcRyas6JgsW9pqQQK5xCYPnKrI0Bj3wGpyOnKIjs5bvWyNnWp5ylwz1xs+qXiQ0IHe3jKM X-Received: by 2002:a17:90b:3c47:b0:286:8abe:8e57 with SMTP id pm7-20020a17090b3c4700b002868abe8e57mr5137111pjb.20.1702264380582; Sun, 10 Dec 2023 19:13:00 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702264380; cv=none; d=google.com; s=arc-20160816; b=Gq/NMv5QfMxgxX/CfBQGekC7iNlyTutHv6nE5bGRt+HnCHTrjXcLxpUVnLUQzBek9A qAhfHp3SCSy/j+AQLRObd7PA8PYnBWC6hSAMX6nc3kKK8bPjEOWQhG5rovjrz9WatLSI tcpBctQiKtzwj0y6Wxam+sp4JcJ2B8LpDi5fSA6ZkA2ngPvwH0UHquYCmdyZ2O8q8Hu9 2WsMuVIlo9k/10f7UCw/VsM6x60b2rK59nmuInLLtTGjiA4HFrUXl4tq0Z3aISVRu8kj i9+2k+z0x9HBDnpZc6BKqUl0CNfbBTFCJ0LnzXvVMrI51ITWCl2bKAQSQQTiG8qiJyDa x5WA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:subject:cc:to:from:date; bh=4ihrkM+ox4ROHzYnX2fjtGmIIzvyH8iIYb7wes0hsEc=; fh=10neyeg9SpQc0WdV4aMamIFr7tikcy7JJ0bptR+ICfw=; b=OyjWt+/hm/Yde/Fs4lFjkIauit4Wqcev8GvDWmNLa2t5np8dh9vj9YKeZvDdwTVafn ODmox7LMUBalZHo0JY18pPxCMksH0gkX90MLvMNDKYvUQKBEY0JeVP3jkgAVpEBMsldl mdfq0mVpXLb/LVxZ2Z355Q7UetctnBo7acBETonIzw7mlWK9d3iKqGrYPw0Tnw+uHych bm8PBGEVbtV22FRDww6HkCUyK/LmJkR+UxDQyqyFe7ojPWak+4bCMOqYiLGCXvJ4J+5q rXEIU6NGK+j0aclOfwbJBN+20ULWJZAUCOOFn1l8iaTaTdq0xE7M9/rJgWIGUa/uHrNY hFsQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from howler.vger.email (howler.vger.email. [23.128.96.34]) by mx.google.com with ESMTPS id x14-20020a17090a46ce00b002867eb143afsi6705976pjg.133.2023.12.10.19.13.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 10 Dec 2023 19:13:00 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) client-ip=23.128.96.34; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by howler.vger.email (Postfix) with ESMTP id 564198060532; Sun, 10 Dec 2023 19:12:57 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at howler.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229589AbjLKDMs (ORCPT + 99 others); Sun, 10 Dec 2023 22:12:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229448AbjLKDMq (ORCPT ); Sun, 10 Dec 2023 22:12:46 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 676829D for ; Sun, 10 Dec 2023 19:12:53 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C81DCC433C8; Mon, 11 Dec 2023 03:12:51 +0000 (UTC) Date: Sun, 10 Dec 2023 22:12:50 -0500 From: Steven Rostedt To: LKML , Linux trace kernel Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers Subject: [PATCH] ring-buffer: Fix memory leak of free page Message-ID: <20231210221250.7b9cc83c@rorschach.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on howler.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Sun, 10 Dec 2023 19:12:57 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784953575200432309 X-GMAIL-MSGID: 1784953575200432309 From: "Steven Rostedt (Google)" Reading the ring buffer does a swap of a sub-buffer within the ring buffer with a empty sub-buffer. This allows the reader to have full access to the content of the sub-buffer that was swapped out without having to worry about contention with the writer. The readers call ring_buffer_alloc_read_page() to allocate a page that will be used to swap with the ring buffer. When the code is finished with the reader page, it calls ring_buffer_free_read_page(). Instead of freeing the page, it stores it as a spare. Then next call to ring_buffer_alloc_read_page() will return this spare instead of calling into the memory management system to allocate a new page. Unfortunately, on freeing of the ring buffer, this spare page is not freed, and causes a memory leak. Cc: stable@vger.kernel.org Fixes: 73a757e63114d ("ring-buffer: Return reader page back into existing ring buffer") Signed-off-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a38e5a3c6803..dd37d21d6e55 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1790,6 +1790,8 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer) free_buffer_page(bpage); } + free_page((unsigned long)cpu_buffer->free_page); + kfree(cpu_buffer); }